Bartosz Wasag
Research interests
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InterestsCancer Biology
Other
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LanguagesPolish, English
Publications
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3.71Impact points
Molecular characterization of two novel KIT mutations in patients with piebaldism.
Journal of dermatological science. 12/2011;
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3.11Impact points
Novel, activating KIT-N822I mutation in familial cutaneous mastocytosis.
Experimental hematology. 05/2011; 39(8):859-65.e2.
We report the rare family in which cutaneous mastocytosis was diagnosed in the father and two children, with urticaria pigmentosa as the only manifestation of the disease. The diagnosis of mastocytosis in the father included bone marrow histopathological and cytological examinations and flow cytomet... [more] We report the rare family in which cutaneous mastocytosis was diagnosed in the father and two children, with urticaria pigmentosa as the only manifestation of the disease. The diagnosis of mastocytosis in the father included bone marrow histopathological and cytological examinations and flow cytometry, and histopathological examination of the skin. In the children, tryptase measurement and skin histopathological examination were performed. Blood, urine, and buccal swab specimens were collected from the family members. HEK293T cells were transiently transfected with plasmids expressing KIT-WT and KIT-N882I. In addition, Ba/F3 cell lines expressing KIT-N822I, KIT-D816V, and KIT-V559D mutants were treated with imatinib and dasatinib. The effect of treatment on proliferation, survival, and signaling was determined. Germ-line KIT-N822I missense mutation was detected in the affected members of the family. Western blot analysis using HEK293T and Ba/F3 cells expressing KIT-N822I isoform showed that KIT-N822I constitutively activated KIT tyrosine phosphorylation. In vitro assays on KIT-N822I-expressing Ba/F3 cells confirmed that the N822I mutant is resistant to imatinib mesylate. In contrast, a high efficacy of dasatinib toward the KIT-N822I-expressing Ba/F3 cells was observed. We provided evidence that KIT p.N822I mutation has transforming potential and can cause a constitutive activation of KIT. In addition, we demonstrated that KIT-N822I is resistant to imatinib and sensitive to dasatinib. Finally, our findings support the hypothesis that not only KIT mutations but other additional genetic abnormalities are contributing to more advanced forms of the disease.
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6.42Impact points
The kinase inhibitor TKI258 is active against the novel CUX1-FGFR1 fusion detected in a patient with T-lymphoblastic leukemia/lymphoma and t(7;8)(q22;p11).
Haematologica. 02/2011; 96(6):922-6.
We report a patient with T-lymphoblastic leukemia/lymphoma and a t(7;8)(q22;p11). CUX1 was identified as the fusion partner of FGFR1 by fluorescence in situ hybridization and 5' RACE-PCR. We further investigated this novel FGFR1 fusion using the interleukin-3 (IL-3) dependent Ba/F3 cell line and... [more] We report a patient with T-lymphoblastic leukemia/lymphoma and a t(7;8)(q22;p11). CUX1 was identified as the fusion partner of FGFR1 by fluorescence in situ hybridization and 5' RACE-PCR. We further investigated this novel FGFR1 fusion using the interleukin-3 (IL-3) dependent Ba/F3 cell line and demonstrated IL-3 independent cell growth of CUX1-FGFR1 expressing cells. TKI258 and PKC412 potently inhibited proliferation of CUX1-FGFR1 transformed Ba/F3 cells. This growth inhibition was shown to be mediated by inhibition of CUX1-FGFR1 kinase activity for TKI258 but not PKC412. In summary, we identified a novel CUX1-FGFR1 fusion oncogene in a patient with the 8p11 myeloproliferative syndrome and demonstrated its transforming potential in the Ba/F3 cell line. Our in vitro data support the further investigation of TKI258 for the treatment of constitutively active FGFR1 fusion proteins.
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1.32Impact points
Molecular characterization of Polish patients with familial hypercholesterolemia: novel and recurrent LDLR mutations.
Journal of applied genetics. 01/2010; 51(1):95-106.
Autosomal dominant hypercholesterolemia (ADH) is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9). In this study, a molecular analysis of LDLR and APOB was performed in a gro... [more] Autosomal dominant hypercholesterolemia (ADH) is caused by mutations in the genes coding for the low-density lipoprotein receptor (LDLR), apolipoprotein B-100 (APOB), or proprotein convertase subtilisin/kexin type 9 (PCSK9). In this study, a molecular analysis of LDLR and APOB was performed in a group of 378 unrelated ADH patients, to explore the mutation spectrum that causes hypercholesterolemia in Poland. All patients were clinically diagnosed with ADH according to a uniform protocol and internationally accepted WHO criteria. Mutational analysis included all exons, exon-intron boundaries and the promoter sequence of the LDLR, and a fragment of exon 26 of APOB. Additionally, the MLPA technique was applied to detect rearrangements within LDLR. In total, 100 sequence variations were identified in 234 (62%) patients. Within LDLR, 40 novel and 59 previously described sequence variations were detected. Of the 99 LDLR sequence variations, 71 may be pathogenic mutations. The most frequent LDLR alteration was a point mutation p.G592E detected in 38 (10%) patients, followed by duplication of exons 4-8 found in 16 individuals (4.2%). Twenty-five cases (6.6%) demonstrated the p.R3527Q mutation of APOB. Our findings imply that major rearrangements of the LDLR gene as well as 2 point mutations (p.G592E in LDLR and p.R3527Q in APOB) are frequent causes of ADH in Poland. However, the heterogeneity of LDLR mutations detected in the studied group confirms the requirement for complex molecular studies of Polish ADH patients.
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Frequency of BCR-ABL gene mutations in Polish patients with chronic myeloid leukemia treated with imatinib: a final report of the MAPTEST study.
Polskie archiwum medycyny wewnȩtrznej. 12/2009; 119(12):789-94.
INTRODUCTION: The presence of BCR-ABL oncogene mutations in patients with chronic myeloid leukemia (CML) may be responsible for the failure of tyrosine kinase inhibitor treatment. OBJECTIVES: The aim of the study was to evaluate the frequency of BCR-ABL gene mutations in patients with CML (the MAPTE... [more] INTRODUCTION: The presence of BCR-ABL oncogene mutations in patients with chronic myeloid leukemia (CML) may be responsible for the failure of tyrosine kinase inhibitor treatment. OBJECTIVES: The aim of the study was to evaluate the frequency of BCR-ABL gene mutations in patients with CML (the MAPTEST study) treated with imatinib (IM). PATIENTS AND METHODS: Direct sequencing analysis of BCR-ABL gene was performed in 92 patients treated with IM for more than 3 months. The mean time of IM treatment was 18 months. At the time of the analysis, 75 patients were in the first chronic phase (CP), 4 in the second CP, 5 in the acceleration and 8 in the blastic phase. Fifty-seven patients (62%) were treated with IM at a daily dose of 400 mg and 35 patients with higher doses (600 or 800 mg daily). Inclusion criteria were based on the European Leukemia Net definitions for failure and suboptimal response to IM. RESULTS: Twelve mutations were detected in 11 of 92 patients, including 4 mutations (36.7%) diagnosed during CP, 3 (27.3%) in acceleration, and 4 (36.7%) in blast crisis. In 1 patient with lymphoid blast crisis of CML coexisting F359V and Y253F mutations were detected. In the whole group mutations were detected in 2 of 5 patients (40%) with primary resistance (M351T, F359V + Y253F) and in 9 of 87 patients (10.3%) (E255K, T315I-3x, M351T, E355G, F359V-2x) with acquired resistance to IM. CONCLUSIONS: The study confirmed the usefulness of BCR-ABL gene mutation screening in patients with CML resistant to IM therapy.
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6.75Impact points
Activity of Dasatinib, a Dual SRC/ABL Kinase Inhibitor, and IPI-504, a Heat Shock Protein 90 Inhibitor, against Gastrointestinal Stromal Tumor-Associated PDGFRAD842V Mutation.
Clinical cancer research : an official journal of the American Association for Cancer Research. 09/2008; 14(18):5749-58.
PURPOSE: Activating mutations in platelet-derived growth factor receptor-alpha (PDGFRA) have been reported in approximately 5% to 10% of patients with gastrointestinal stromal tumors (GIST). Imatinib efficiently inhibits the juxtamembrane PDGFRA mutations, whereas many tyrosine kinase domain activat... [more] PURPOSE: Activating mutations in platelet-derived growth factor receptor-alpha (PDGFRA) have been reported in approximately 5% to 10% of patients with gastrointestinal stromal tumors (GIST). Imatinib efficiently inhibits the juxtamembrane PDGFRA mutations, whereas many tyrosine kinase domain activation loop PDGFRA mutations confer primary resistance to imatinib. In this study, we compared the efficacy of second-line tyrosine kinase inhibitors such as dasatinib, sorafenib, and nilotinib against two GIST-related PDGFRA mutants, PDGFRA(D842V) and PDGFRA(DeltaDIM842-844). In addition, we sought to investigate the inhibitory effect of the heat shock protein 90 inhibitor, IPI-504, on these mutants. EXPERIMENTAL DESIGN: Primary imatinib-resistant tumor cells and cell lines expressing imatinib-resistant PDGFRA(D842V) or imatinib-sensitive PDGFRA(DeltaDIM842-844) mutants were treated with different concentrations of dasatinib, sorafenib, nilotinib, and IPI-504. The effect of treatment on proliferation, survival, and signaling was determined. RESULTS: All inhibitors tested exhibited a high efficacy toward the PDGFRA(DeltaDIM842-844) mutant. In contrast, ex vivo and in vitro assays revealed that only dasatinib potently inhibited the PDGFRA(D842V) isoform with an IC(50) value of 62 nmol/L. Sorafenib and nilotinib were significantly less efficacious against this mutation, inhibiting the PDGFRA kinase activity at >1,000 and >5,000 nmol/L, and suppressing the proliferation of the cells expressing the PDGFRA(D842V) mutant with an IC(50) value of 239 and 1,310 nmol/L, respectively. IPI-504 treatment potently inhibited PDGFRA kinase activity by inducing the degradation of PDGFRA(D842V) and PDGFRA(DeltaDIM842-844) at 256 and 182 nmol/L, respectively. CONCLUSIONS: Treatment with dasatinib or the heat shock protein 90 inhibitor IPI-504 may provide a therapeutic alternative for GIST patients whose tumors carry the imatinib-resistant PDGFRA(D842V) mutant isoform.
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4.60Impact points
Presence of homozygous KIT exon 11 mutations is strongly associated with malignant clinical behavior in gastrointestinal stromal tumors.
Laboratory investigation; a journal of technical methods and pathology. 11/2007; 87(10):1029-41.
Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs range from benign indolent neoplasms to highly malignant sarcomas. Gain-of-function mutations of tyrosine kinase receptors, KIT or PDGFRA, have been identified in most GISTs. In this study... [more] Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of gastrointestinal tract. GISTs range from benign indolent neoplasms to highly malignant sarcomas. Gain-of-function mutations of tyrosine kinase receptors, KIT or PDGFRA, have been identified in most GISTs. In this study, we report 36 GIST patients whose tumors had homozygous KIT exon 11 mutations detected by direct sequencing of PCR products. Loss of heterozygosity in KIT locus and other chromosome 4 loci were documented in majority of these tumors. However, fluorescence in situ hybridization with KIT locus-specific probe and chromosome 4 centromeric enumeration probe showed no evidence of KIT hemizygosity in a majority of analyzed cases. These findings are consistent with duplication of chromosome 4 with KIT mutant allele. Homozygous KIT exon 11 mutations were found in 33 primary tumors and 7 metastatic lesions. In two cases, shift from heterozygosity to homozygosity was documented during tumor progression being present in metastases, but not in primary tumors. Among primary GISTs, there were 16 gastric, 18 intestinal and 2 from unknown locations. An average primary tumor size was 12 cm and average mitotic activity 32/50 HPFs. Out of 32 tumors 29 (90.6%) with complete clinicopathologic data were diagnosed as sarcomas with more than 50% risk of metastatic disease, and 26 of 29 patients with follow-up had metastases or died of disease. An average survival time among pre-imatinib patients, who died of the disease was 33.4 months. Based on these findings, we conclude that presence of homozygous KIT exon 11 mutations is associated with malignant course of disease and should be considered an adverse prognostic marker in GISTs.
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1.75Impact points
Mutations in gastrointestinal stromal tumors--a population-based study from Northern Norway.
APMIS : acta pathologica, microbiologica, et immunologica Scandinavica. 05/2007; 115(4):289-98.
Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. This tumor typically expresses KIT, and has KIT or PDGFRA activating mutation. In this study we evaluated 89 GISTs diagnosed in Northern Norway during a 30-year period. KIT exons 8, 9, 11, 13, a... [more] Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. This tumor typically expresses KIT, and has KIT or PDGFRA activating mutation. In this study we evaluated 89 GISTs diagnosed in Northern Norway during a 30-year period. KIT exons 8, 9, 11, 13, and 17 were analyzed by PCR amplification and direct sequencing. Subsequently PDGRA exons 12, 14, and 18 were evaluated in KIT wild-type cases. KIT mutations were found in 66 cases (75%), and PDGFRA mutations in 9 cases (10%). Most common were KIT exon 11 mutations, with 58 cases. Tumors with Kit exon 11 point mutations had a significantly better prognosis than those with deletions. There were five KIT exon 9 duplications, three exon 13 point mutations, and one point mutation in exon 17. There were nine PDGFGRA mutations: seven in exon 18 and two in exon 12. All but one PDGFRA mutant GISTs were gastric tumors with epithelioid morphology, and these tumors were on average smaller than those with KIT mutations. KIT and PDGFRA wild type was found in 15% of cases. Analysis of KIT and PDGFRA mutations is of significance for treatment with tyrosine kinase inhibitors, and may also have value when assessing the biological potential of GIST.
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3.86Impact points
Array CGH analysis in primary gastrointestinal stromal tumors: cytogenetic profile correlates with anatomic site and tumor aggressiveness, irrespective of mutational status.
Genes, chromosomes & cancer. 04/2007; 46(3):261-76.
Gastrointestinal stromal tumors (GISTs) comprise a biologically diverse group of neoplasms with respect to activating mutations in either KIT or PDGFRA, histology, anatomical site of origin, and clinical aggressiveness. In this study, we applied the high resolution array-based comparative genomic hy... [more] Gastrointestinal stromal tumors (GISTs) comprise a biologically diverse group of neoplasms with respect to activating mutations in either KIT or PDGFRA, histology, anatomical site of origin, and clinical aggressiveness. In this study, we applied the high resolution array-based comparative genomic hybridization (array-CGH) technology to 66 primary GISTs (40 gastric and 26 nongastric, 48 with KIT and 18 with PDGFRA mutations) for identification of novel high-level alterations and for characterization of genotype-related genomic changes. All cases had genomic imbalances with the highest occurrence of 14q (73%), 1p (62%), 22q (59%), 15q (38%), and 13q (29%) losses. Our data indicate that loss of chromosome 14 and/or 22 is an early change in GIST tumorigenesis irrespective of tumor genotype. Furthermore, DNA copy number changes showed a site dependent pattern. These included lower incidence of losses at 14q (87% vs. 35%), and higher frequency of losses at 1p (45% vs. 85%) and 15q (17% vs. 69%) in nongastric versus gastric site (P<0.001 for all). However, in the multivariate analysis with adjustment to tumor risk stratification, only the 14q loss site-dependent pattern of distribution retained its significance. These findings suggest that loss of 14q is a relatively less frequent genetic event in the development of nongastric GISTs, the lack of which is most likely substituted by the accumulation of 1p/15q and other changes. The novel minimal overlapping regions of deletion at 1p (1p36.32-1p35.2, 1p34.1, and 1p22.1-1p21.3), 13q (13q14.11-q14.2 and 13q32.3-q33.1), and 15q23 were delineated, which point to chromosomal regions that may harbor genes relevant to the development of these neoplasms.
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3.48Impact points
Improved detection of KIT exon 11 duplications in formalin-fixed, paraffin-embedded gastrointestinal stromal tumors.
The Journal of molecular diagnostics : JMD. 03/2007; 9(1):89-94.
Gastrointestinal stromal tumors (GISTs) are the most common gastrointestinal mesenchymal tumors driven by KIT or PDGFRA mutations. A majority of these mutations affect KIT exon 11 and represent deletions or point mutations, but insertions and duplications have also been reported. The latter have bee... [more] Gastrointestinal stromal tumors (GISTs) are the most common gastrointestinal mesenchymal tumors driven by KIT or PDGFRA mutations. A majority of these mutations affect KIT exon 11 and represent deletions or point mutations, but insertions and duplications have also been reported. The latter have been found exclusively in the 3' part of KIT exon 11. Reported frequency of duplications varies, and a higher frequency has been reported in studies based on frozen tissue. Recently, we have hypothesized that in some cases, the duplications might remain undetected in formalin-fixed, paraffin-embedded GISTs because of the preferential polymerase chain reaction (PCR) amplification of wild-type KIT over the mutant allele. In this study, 16 GISTs initially diagnosed as a wild-type KIT were evaluated using PCR assay amplifying only the 3' part of KIT exon 11, the region commonly affected by duplications. Denaturing high-pressure liquid chromatography and direct sequencing analyses revealed duplications in 4 (25%) of 16 analyzed cases. Use of the PCR assay amplifying the specific region affected by duplications and yielding 129 bp in wild-type KIT can substantially improve the detection of these mutations in formalin-fixed, paraffin-embedded GISTs.
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12.90Impact points
Mechanisms of resistance to imatinib mesylate in gastrointestinal stromal tumors and activity of the PKC412 inhibitor against imatinib-resistant mutants.
Gastroenterology. 03/2005; 128(2):270-9.
BACKGROUND AND AIMS: Resistance is a major challenge in the treatment of patients with gastrointestinal stromal tumors (GISTs). We investigated the mechanisms of resistance in patients with progressive GISTs with primary KIT mutations and the efficacy of the kinase inhibitor PKC412 for the inhibitio... [more] BACKGROUND AND AIMS: Resistance is a major challenge in the treatment of patients with gastrointestinal stromal tumors (GISTs). We investigated the mechanisms of resistance in patients with progressive GISTs with primary KIT mutations and the efficacy of the kinase inhibitor PKC412 for the inhibition of imatinib-resistant mutants. METHODS: We performed a cytogenetic analysis and screened for mutations of the KIT and PDGFRA kinase domains in 26 resistant GISTs. KIT autophosphorylation status was assessed by Western immunoblotting. Imatinib-resistant GIST cells and Ba/F3 cells expressing these mutant proteins were tested for sensitivity to imatinib and PKC412. RESULTS: Six distinct secondary mutations in KIT were detected in 12 progressive tumors, with V654A and T670I found to be recurrent. One progressive tumor showed acquired PDGFRA -D842V mutation. Amplification of KIT or KIT / PDGFRA was found in 2 patients. Eight of 10 progressive tumors available for analysis showed phosphorylated KIT. Two remaining progressive tumors lost KIT protein expression. GIST cells carrying KIT -del557-558/T670I or KIT -InsAY502-503/V654A mutations were resistant to imatinib, while PKC412 significantly inhibited autophosporylation of these mutants. Resistance to imatinib and sensitivity to PKC412 of KIT -T670I and PDGFRA -D842V mutants was confirmed using Ba/F3 cells. CONCLUSIONS: This study shows the high frequency of KIT/PDGFRA kinase domain mutations in patients with secondary resistance and defines genomic amplification of KIT / PDGFRA as an alternative cause of resistance to the drug. In a subset of patients, cancer cells lost their dependence on the targeted tyrosine kinase. Our findings show the sensitivity of the imatinib-resistant KIT -T670I and KIT -V654A and of PDGFRA -D842V mutants to PKC412.
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[Systemic mastocytosis]
Pneumonologia i alergologia polska : organ Polskiego Towarzystwa Ftyzjopneumonologicznego, Polskiego Towarzystwa Alergologicznego, i Instytutu Gruźlicy i Chorób Płuc. 02/2005; 73(3):239-44.
Mastocytosis is group of rare disorders characterized by abnormal mast cells growth. Pathology of the disease is unknown, mechanisms involved in mast cells delineation and growth are considered to play an important role. Unusual and broad spectrum of symptoms therefore requires cooperation of differ... [more] Mastocytosis is group of rare disorders characterized by abnormal mast cells growth. Pathology of the disease is unknown, mechanisms involved in mast cells delineation and growth are considered to play an important role. Unusual and broad spectrum of symptoms therefore requires cooperation of different specialists. The aim of the study was to assess diagnostic and therapeutic methods used in the Gdansk Mastocytosis Centre. 14 patients were studied (9 adults and 5 children). Bone marrow biopsy was performed in order to assess the stage of disease. Pathological, cytological, cytofotometry and genetic examination (C-KIT mutation) of the bone marrow were performed. Patients suffereing from food allergy and wasp venom anaphylaxis were diagnosed with skin prick tests and sIgE. All subjects suffered from urticaria pigmenthosa and anaphylaxis. Indolent mastocytosis was diagnosed in six subjects. Patients were treated with antihistamines, corticosteroids, cromones and immunotherapy with a marked reduction of symptoms. The experience of Gdansk Mastocytosis Centre indicates that mastocytosis is a rare and difficult to diagnose disease.
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4.29Impact points
Differential expression of KIT/PDGFRA mutant isoforms in epithelioid and mixed variants of gastrointestinal stromal tumors depends predominantly on the tumor site.
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc. 09/2004; 17(8):889-94.
Gastrointestinal stromal tumors (GISTs) form a distinctive group of mesenchymal neoplasms, showing differentiation towards the interstitial cells of Cajal. Morphologically, GISTs vary from cellular spindle cell tumors to epithelioid or mixed, epithelioid and spindle cell variants. The genotypic feat... [more] Gastrointestinal stromal tumors (GISTs) form a distinctive group of mesenchymal neoplasms, showing differentiation towards the interstitial cells of Cajal. Morphologically, GISTs vary from cellular spindle cell tumors to epithelioid or mixed, epithelioid and spindle cell variants. The genotypic features underlying the morphologic differences of GISTs with vs without epithelioid components are not well defined. Acquisition of activating mutations in KIT and PDGFRA has been reported as alternative oncogenic events in the pathogenesis of GISTs. In this study, a comprehensive KIT and PDGFRA mutational analysis was performed in a group of 28 epithelioid/mixed type tumors, in order to explore whether a specific KIT/PDGFRA mutational status segregates these neoplasms from spindle cell variant GISTs. All GISTs were primary neoplasms, 16 (57.1%) originated from the stomach and 12 (42.8%) from other locations. Histomorphologically, 14 GISTs showed an epithelioid and 14 a mixed cell type pattern. Mutational analysis included KIT exons 9, 11, 13, and 17, and PDGFRA exons 12 and 18 prescreening by denaturing high-performance liquid chromatography, followed by direct sequencing. Activating mutations of KIT were found in 14 (50%) GISTs, the majority being within exon 11 (n=11; 39.2%), and the other comprised exon 9 AY 502-503 duplications (n=2; 7.2%) and exon 17 Lys --> Aln822 missense mutations (n=1; 3.6%). Most of the KIT mutant tumors (n=11; 78.6%) originated from nongastric sites. Seven (25.0%) GISTs with no detectable KIT mutations demonstrated PDGFRA mutant isoforms, carrying either D842 V mutations (n=5) or exon 18 deletions (n=2). All GISTs harboring PDGFRA mutant isoforms originated from the stomach. In seven tumors, no detectable mutations were found; all but one of nonmutant tumors initiated from the stomach and exhibited an epithelioid morphology. These findings indicate that the mutational status of epithelioid/mixed GISTs associates with the anatomical site of the tumor.
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6.47Impact points
Gastrointestinal stromal tumours (GISTs) negative for KIT (CD117 antigen) immunoreactivity.
The Journal of pathology. 04/2004; 202(4):430-8.
Gastrointestinal stromal tumours (GISTs) are currently defined as mesenchymal tumours of the gastrointestinal tract that express KIT receptor tyrosine kinase. However, a small subgroup of tumours that fulfil the clinical and morphological criteria for GISTs lack KIT expression. So far, the biologica... [more] Gastrointestinal stromal tumours (GISTs) are currently defined as mesenchymal tumours of the gastrointestinal tract that express KIT receptor tyrosine kinase. However, a small subgroup of tumours that fulfil the clinical and morphological criteria for GISTs lack KIT expression. So far, the biological features of these tumours have rarely been addressed. The present study describes seven gastrointestinal stromal neoplasms that presented clinicopathological features typical of GISTs but showed absence of CD117 expression as detected by immunohistochemistry. The tumours originated from the stomach (n = 5), duodenum (n = 1), and colon (n = 1), showing histologically either predominantly epithelioid (n = 3), mixed spindled and epithelioid (n = 2), or anaplastic/spindle cell (n = 2) type features. CD34 and alpha-smooth muscle actin (alpha-SMA) positivity was present in four and three tumours, respectively. Chromosomal analysis was performed in two cases, both showing losses of chromosomes 14, 22, and 1p, which is the characteristic feature of GISTs. Dual-colour interphase fluorescence in situ hybridization (FISH) analysis, utilizing chromosome 1p-, 14-, and 22-specific probes, revealed a similar cytogenetic profile in the remaining five tumour specimens. Mutational analysis of exons 9, 11, 13, and 17 of KIT, and exons 12 and 18 of PDGFRA was performed in all cases by denaturing high-pressure liquid chromatography (DHPLC) pre-screening, followed by direct sequencing. None of the tumours showed KIT mutant isoforms. Three tumours harboured PDGFRA exon 18 activating mutations; two were Asp --> Val(842) missense substitutions and one was a DIM842-844 amino acid deletion. KIT and PKC theta (protein activated in interstitial cells of Cajal and GISTs) expression was determined by western immunoblotting of the total cell lysates from three tumour biopsies. None of these three tumours expressed KIT, while all specimens showed expression of PKC theta protein. These findings indicate that there is a subgroup of KIT-negative GISTs that exhibit the same morphological, cytogenetic, and molecular features as KIT-positive tumours. While intragenic PDGFRA activating mutations are present in some of these tumours, the oncogenic events underlying the pathogenesis of the others remain unknown.
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4.12Impact points
Use of c-KIT/PDGFRA mutational analysis to predict the clinical response to imatinib in patients with advanced gastrointestinal stromal tumours entered on phase I and II studies of the EORTC Soft Tissue and Bone Sarcoma Group.
European journal of cancer (Oxford, England : 1990). 04/2004; 40(5):689-95.
Previous studies have shown that activating mutations of c-KIT/PDGFRA, potential therapeutic targets for imatinib mesylate, are implicated in the pathophysiology of gastrointestinal stromal tumours (GISTs). In this study, GISTs from 37 patients enrolled in an European Organisation for Research and T... [more] Previous studies have shown that activating mutations of c-KIT/PDGFRA, potential therapeutic targets for imatinib mesylate, are implicated in the pathophysiology of gastrointestinal stromal tumours (GISTs). In this study, GISTs from 37 patients enrolled in an European Organisation for Research and Treatment of Cancer (EORTC) phase I/II clinical study of imatinib were examined for mutations of c-KIT/PDGFRA in order to explore whether the mutational status of the tumour predicts the clinical response to therapy. Mutations were screened by denaturing high-pressure liquid chromatography (DHPLC) and characterised by bi-directional DNA sequencing. Activating mutations of c-KIT or PDGFRA were found in 29 (78%) and 2 (6%) GISTs, respectively. Most c-KIT mutations involved exon 11 (n=24; 83%), all but one being an in-frame deletion; no isolated point mutations were found. The other c-KIT mutations included exon 9 AY 502-503 duplication (n=4; 14%) and exon 13 Lys-->Glu(642) missense mutation (n=1; 3%). Two tumours with no detectable c-KIT mutations demonstrated PDGFRA Asp-->Glu(842) amino acid substitutions. Patients with GISTs harbouring exon 11 mutations were more likely to achieve a partial response (PR) on imatinib therapy (83%) than all of the others (23%). The overall survival and progression-free survival rates for the entire group at 106 weeks were 78.3% and 46.9%, respectively. Based on a Kaplan-Meier analysis, patients with GISTs harbouring c-KIT mutations had longer median survival times and were less likely to progress than the other patients. These findings indicate that the mutational status of the c-KIT/PDGFRA oncoproteins could be useful to predict the clinical response of patients imatinib therapy.
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1.89Impact points
Left ventricular size, mass and function in relation to angiotensin-converting enzyme gene and angiotensin-II type 1 receptor gene polymorphisms in patients with coronary artery disease.
Clinical chemistry and laboratory medicine : CCLM / FESCC. 05/2003; 41(4):522-8.
The objective of the present study was to analyse the potential synergistic influence of the insertion/deletion polymorphism of the angiotensin-converting enzyme gene (I/D ACE) and the A1166C polymorphism of the angiotensin-II type 1 receptor gene polymorphisms (A1166C AT1R) on the left ventricular ... [more] The objective of the present study was to analyse the potential synergistic influence of the insertion/deletion polymorphism of the angiotensin-converting enzyme gene (I/D ACE) and the A1166C polymorphism of the angiotensin-II type 1 receptor gene polymorphisms (A1166C AT1R) on the left ventricular size and performance. Three hundred sixty and one consecutive, Caucasian patients with angiographically confirmed coronary artery disease (CAD) were enrolled into the study. Left ventricular diameter, mass and function were evaluated by echocardiography. Screening for the I/D ACE and A1166C AT1R genotypes was performed by polymerase chain reaction of genomic DNA, followed by restriction enzyme digestion and agarose gel electrophoresis. The I/D ACE and A1166C AT1R genotypes separately were not significantly associated with the left ventricular size and function parameters in CAD patients. However, trends towards decreased left ventricular ejection fraction (LVEF) as well as increased left ventricular end-diastolic diameter (LVEDD) and left ventricular mass index (LVMI) were observed when patients with genotype DD+CC/AC and DD+CC were compared to patients homozygous only in one locus (DD or CC). Significant increase in LVEDD and LVMI was observed only in patients with a history of anterior myocardial infarction with combined genotype DD+CC/AC or DD+CC. This study does not support the role of the ACE I/D and AT1R A1166C polymorphisms in the determination of the left ventricular size and performance in patients with significant coronary atherosclerosis. However, it indicates that the influence of polymorphisms may be present in specific patient populations.
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3.47Impact points
Association between the Pl(A) platelet glycoprotein GPIIIa polymorphism and extent of coronary artery disease.
International journal of cardiology. 04/2003; 88(2-3):229-37.
BACKGROUND: The Pl(A2) allele of the gene encoding for GPIIIa subunit of the platelet membrane receptor glycoprotein (GP) IIb/IIIa has been suggested as a significant risk factor for thrombotic complications of coronary artery disease (CAD). The aim of the current investigation was to investigate th... [more] BACKGROUND: The Pl(A2) allele of the gene encoding for GPIIIa subunit of the platelet membrane receptor glycoprotein (GP) IIb/IIIa has been suggested as a significant risk factor for thrombotic complications of coronary artery disease (CAD). The aim of the current investigation was to investigate the association between Pl(A) GPIIIa polymorphism and the extent of angiographically confirmed CAD in patients from the north region of Poland. METHODS: The study was performed in 397 male Caucasian patients. All subjects had significant coronary artery stenosis confirmed by elective coronary angiography. Screening for the Pl(A) GPIIIa genotypes was performed by polymerase chain reaction of genomic DNA, followed by NciI digestion and agarose gel electrophoresis. RESULTS: The genotype distribution of the Pl(A) GPIIIa polymorphism in our study group was Pl(A1/A1)-75%, Pl(A1/A2)-24% and Pl(A2/A2)-1% with Pl(A1) and Pl(A2) allele frequencies of 0.87 and 0.13, respectively. The prevalence of the homozygous Pl(A1/A1) genotype among subjects with multiple-vessel CAD (two or three vessels with at least 50% stenosis) was significantly higher than in patients with single-vessel disease; the odds ratio of Pl(A2/A2) or Pl(A1/A2) patients for having multiple-vessel CAD was 0.46 (95% CI 0.27-0.77, P<0.01). The mean CAD score for Pl(A1/A1) patients was significantly higher in comparison to Pl(A2/A2) and Pl(A1/A2) patients (7.58+/-2.20 and 6.98+/-2.37, respectively, P<0.05). CONCLUSIONS: Our results suggest, that the Pl(A1/A1) genotype of Pl(A) GPIIIa polymorphism is associated with more severe CAD in male Caucasian patients from the north region of Poland.
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2.75Impact points
A unique occurrence of a cerebral atypical teratoid/rhabdoid tumor in an infant and a spinal canal primitive neuroectodermal tumor in her father.
Journal of neuro-oncology. 02/2003; 61(3):219-25.
This report describes the clinical, pathological, immunohistochemical and genetic data of two rare malignant neoplasms of the central nervous system (CNS)--a cerebral atypical teratoid/rhabdoid tumor (AT/RT) in a 5-month-old girl and a spinal canal primitive neuroectodermal tumor (PNET) in her fathe... [more] This report describes the clinical, pathological, immunohistochemical and genetic data of two rare malignant neoplasms of the central nervous system (CNS)--a cerebral atypical teratoid/rhabdoid tumor (AT/RT) in a 5-month-old girl and a spinal canal primitive neuroectodermal tumor (PNET) in her father. Despite aggressive treatment, both tumors were fatal, displaying extensive local recurrence and diffuse neoplastic dissemination. The paraffin-embedded tumor tissue samples were analyzed using a dual-color FISH with a locus specific LSI22q (BCR) probe. In the AT/RT tissue, a loss of BCR locus was observed in a significant proportion of the cells in contrast to the PNET specimen where the majority of nuclei did not reveal any loss of the BCR region. No mutations in exon 5 and no changes in SNP of intron 5 of hSNF/INI1 gene were found. In addition, analysis of loss of heterozygosity (LOH) was performed using a panel of 15 microsatellite markers of chromosome 22. No LOH were found in both tumor tissues. In both cases no constitutional mutations of gene TP53 were found. Analysis of the TP53 mutations in the tumor tissues revealed that the PNET, not the AT/RT tumor, was homozygous for a missense mutation at codon 175 (CGC ==> CAC). Thus, our findings emphasize the genetic differences between the two specimens and suggest that the occurrence of these two aggressive tumors of CNS in one family could be coincidental.
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4.36Impact points
Association of the ScaI atrial natriuretic peptide gene polymorphism with nonfatal myocardial infarction and extent of coronary artery disease.
American heart journal. 01/2003; 145(1):125-31.
BACKGROUND: There is growing evidence from recent studies that atrial natriuretic peptide (ANP) plays an important part in coronary blood flow regulation and in atherosclerosis. Transition T2238-->C in the atrial natriuretic peptide (ANP) precursor gene, which leads potentially to the translation... [more] BACKGROUND: There is growing evidence from recent studies that atrial natriuretic peptide (ANP) plays an important part in coronary blood flow regulation and in atherosclerosis. Transition T2238-->C in the atrial natriuretic peptide (ANP) precursor gene, which leads potentially to the translation of ANP with 2 additional arginines, has been suggested to be associated with salt-sensitive hypertension. According to our knowledge, this study is the first to look for the potential association of the ScaI ANP gene polymorphism with the history of nonfatal myocardial infarction and the extent of coronary artery disease (CAD). METHODS: The study was performed in 847 consecutive, white patients (719 men and 128 women) with significant coronary artery stenosis confirmed by means of elective coronary angiography (at least 1 coronary artery with > or =50% lumen narrowing). Screening for the T2238-->C substitution was performed by means of polymerase chain reaction of genomic DNA, followed by ScaI digestion and agarose gel electrophoresis. RESULTS: We found a significant association of the A2A2 ScaI ANP genotype with a higher incidence of positive history of nonfatal myocardial infarction (odds ratio 1.85, 95% CI 1.33-2.58) and multiple-vessel CAD (odds ratio 1.45, 95% CI 1.02-2.06). The ScaI ANP genotype distribution did not differ with age, sex, body mass index, plasma lipids, hypertension, diabetes mellitus, and family history of CAD in studied groups. CONCLUSIONS: Our results suggest that the ScaI ANP polymorphism may be associated with nonfatal myocardial infarction and the extent of CAD. However, the precise mechanism of this association remains to be determined.
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5.49Impact points
The neurofibromatosis type 2 gene is mutated in perineurial cell tumors: a molecular genetic study of eight cases.
The American journal of pathology. 04/2001; 158(4):1223-9.
Perineurial cell tumors (PNTs) are rare neoplasms derived from or showing differentiation toward specialized lining cells of the nerve sheath, the perineurial cells. In this study, we have evaluated neurofibromatosis type 2 (NF2) gene alterations in eight PNTs using archival formaldehyde-fixed, para... [more] Perineurial cell tumors (PNTs) are rare neoplasms derived from or showing differentiation toward specialized lining cells of the nerve sheath, the perineurial cells. In this study, we have evaluated neurofibromatosis type 2 (NF2) gene alterations in eight PNTs using archival formaldehyde-fixed, paraffin-embedded tissue. Two conventional soft-tissue PNTs from the upper back and chest wall, one retiform soft tissue variant from the scapular region, and five sclerosing PNTs from the fingers and palm were studied. All cases showed histological features of PNTs, and the neoplastic cells were positive for epithelial membrane antigen and negative for S100 protein. The coding sequences (exons 1 to 15) of the NF2 gene were polymerase chain reaction (PCR) amplified and evaluated for mutations by direct sequencing of the PCR products. Five NF2 point mutations, two in the 5'-untranslated region (UTR) and three in exons 3, 6, and 8, were identified in four of eight cases (50%) studied. Exon mutations resulted in changes of predicted amino acids sequences: Asp-->Asn at codon 83, Glu-->Asp at codon 182, and Leu-->Val at codon 241. In two cases (one with a missense mutation in codon 241), the same point mutation in the 5'-UTR at the nucleotide position 8958 was identified. A loss of heterozygosity (LOH) study was performed in three cases. LOH at the NF2 locus was found in one case with a mutation in the 5'-UTR. However, in another case with exon 8 and 5'-UTR mutations, deletion of one allele of the NF2 gene was previously documented by fluorescence in situ hybridization. The coexistence of NF2 gene mutations and LOH at the NF2 locus indicates that the NF2 tumor suppressor gene is altered in PNTs by the two-hit mechanism.
Following (5)
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Hans Prenen
Katholieke Universiteit Leuven -
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Jan Cools
Katholieke Universiteit Leuven -
Anne Hagemeijer
Katholieke Universiteit Leuven -
Tomasz Sacha
Collegium Medicum of the Jagiellonian University
