Publications (8)40.97 Total impact
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Article: Kappa deleting element as an alternative molecular target for minimal residual disease assessment by real-time quantitative PCR in patients with multiple myeloma.
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ABSTRACT: Minimal residual disease (MRD) assessment by PCR in multiple myeloma (MM) has several shortcomings, including the lack of a suitable target. Kappa deleting element (KDE) rearrangements occur in virtually all Ig-lambda B-cell malignancies and in 1/3 of Ig-kappa are not affected by somatic hypermutation and, as in ALL, could be used as PCR targets. We have first investigated the incidence, gene segment usage, and CDR3 composition of IGK-KDE rearrangements in 96 untreated myeloma patients. Second, we tested 16 KDE gene rearrangements as molecular targets for MRD assessment by RQ-PCR using a germline reverse primer and a germline Taqman probe in combination with allele-specific oligonucleotides (ASO) as forward primers. Monoclonal KDE rearrangements were amplified in 45% (43/96) of cases, monoallelic in 2/3 of them (29 cases), and biallellic in the remaining 14 cases. Overall, 88% of cases were successfully sequenced, KDE being equally frequently rearranged with VK and with intron-Recombination signal sequence (RSS). Median numbers of inserted and deleted nucleotides in the junctional region were one and five, respectively. Using KDE rearrangements as additional PCR target for MRD assessment in MM improves the applicability of these studies in 9% of cases overall and in 20% of lambda cases. Its use in the latter subset could represent a significant advance.European Journal Of Haematology 07/2012; 89(4):328-35. · 2.61 Impact Factor -
Article: Long FLT3 internal tandem duplications and reduced PML-RARα expression at diagnosis characterize a high-risk subgroup of acute promyelocytic leukemia patients.
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ABSTRACT: Internal tandem duplications of the FLT3 gene (FLT3-ITDs) are frequent in patients with acute promyelocytic leukemia (APL), however its clinical impact remains controversial. We analyzed the prognostic significance of FLT3-ITD mutant level and size, as well as FLT3-D835 point mutations, PML-RARalpha expression and other predictive factors in 129 APL patients at diagnosis enrolled on the Spanish LPA96 (n=43) or LPA99 (n=86) PETHEMA trials. FLT3-ITDs and D835 mutations were detected in 21% and 9% of patients, respectively. Patients with increased ITD mutant/wild-type ratio or longer ITD size displayed shorter 5-year relapse-free survival (RFS) (P=0.048 and P<0.0001, respectively). However, patients with D835 mutations did not show differences in RFS or overall survival (OS). Moreover, patients with initial normalized copy number (NCN) of PML-RARalpha transcripts less than the 25(th) percentile had adverse clinical features and shorter 5-year RFS (P<0.0001) and OS (P=0.004) compared to patients with higher NCN. Patients with low NCN showed increased incidence of ITDs (P=0.001), with higher ratios (P<0.0001) and/or longer sizes (P=0.007). Multivariate analysis showed that long FLT3-ITD (P=0.001), low PML-RARalpha levels (P=0.004) and elevated WBC counts (>10x10(9)/L) (P=0.018) were independent predictors for shorter RFS. We identified a subgroup of patients with high WBC, long FLT3-ITD and low NCN of transcripts that showed an extremely bad prognosis (5-year RFS 23.4%, P<0.0001). In conclusion, FLT3-ITD size and PML-RARalpha transcript levels at diagnosis could contribute to improve the risk stratification in APL.Haematologica 05/2010; 95(5):745-51. · 6.42 Impact Factor -
Article: Mapping of genetic abnormalities of primary tumours from metastatic CRC by high-resolution SNP arrays.
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ABSTRACT: For years, the genetics of metastatic colorectal cancer (CRC) have been studied using a variety of techniques. However, most of the approaches employed so far have a relatively limited resolution which hampers detailed characterization of the common recurrent chromosomal breakpoints as well as the identification of small regions carrying genetic changes and the genes involved in them. Here we applied 500K SNP arrays to map the most common chromosomal lesions present at diagnosis in a series of 23 primary tumours from sporadic CRC patients who had developed liver metastasis. Overall our results confirm that the genetic profile of metastatic CRC is defined by imbalanced gains of chromosomes 7, 8q, 11q, 13q, 20q and X together with losses of the 1p, 8p, 17p and 18q chromosome regions. In addition, SNP-array studies allowed the identification of small (<1.3 Mb) and extensive/large (>1.5 Mb) altered DNA sequences, many of which contain cancer genes known to be involved in CRC and the metastatic process. Detailed characterization of the breakpoint regions for the altered chromosomes showed four recurrent breakpoints at chromosomes 1p12, 8p12, 17p11.2 and 20p12.1; interestingly, the most frequently observed recurrent chromosomal breakpoint was localized at 17p11.2 and systematically targeted the FAM27L gene, whose role in CRC deserves further investigations. In summary, in the present study we provide a detailed map of the genetic abnormalities of primary tumours from metastatic CRC patients, which confirm and extend on previous observations as regards the identification of genes potentially involved in development of CRC and the metastatic process.PLoS ONE 01/2010; 5(10):e13752. · 4.09 Impact Factor -
Article: Mesenchymal stem cells are functionally abnormal in patients with immune thrombocytopenic purpura.
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ABSTRACT: Immune thrombocytopenic purpura (ITP) is a bleeding disorder characterized by an accelerated destruction of platelets as a result of the presence of autoreactive antibodies. Patients with ITP also display activated platelet-autoreactive T cells. Mesenchymal stem cells (MSC) inhibit both T- and B-cell activation and may have functional impairments in autoimmune disorders. We analyzed the potential role of MSC in the pathogenesis of ITP. MSC from ITP showed an impaired proliferative capacity and a lower capability of inhibiting activated T-cell proliferation compared with healthy donors. While MSC from controls showed a decreased expression of p27 after stimulation with platelet-derived growth factor, this effect was not observed in MSC from patients. Furthermore, MSC from healthy donors down-regulated p16 upon exposure to platelet-released supernatant, while this effect was not observed for ITP. Interestingly, caspase 9 expression was higher in MSC from ITP. These abnormalities suggest a role of MSC malfunction in the physiopathology of the disease and may have therapeutic implications.Cytotherapy 01/2009; 11(6):698-705. · 3.63 Impact Factor -
Article: The relevance of preferentially expressed antigen of melanoma (PRAME) as a marker of disease activity and prognosis in acute promyelocytic leukemia.
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ABSTRACT: The gene for preferentially expressed antigen of melanoma (PRAME) has been shown to be over-expressed in acute promyelocytic leukemia, but its actual incidence and clinical impact are still unknown. We studied PRAME expression at diagnosis using real-time quantitative polymerase chain reaction in 125 patients with acute promyelocytic leukemia enrolled in the Spanish PETHEMA-96 (n=45) and PETHEMA-99 (n=80) clinical trials. In addition, PRAME expression was evaluated as a marker of disease activity in 225 follow-up samples from 67 patients with acute promyelocytic leukemia. At diagnosis, PRAME expression in patients with acute promyelocytic leukemia was significantly higher (p<0.001) than in patients with non-M3 acute myeloid leukemia (n=213) and in healthy controls (n=10). Furthermore, patients with acute promyelocytic leukemia with high PRAME expression had a favorable outcome. Thus, the 5-year relapse-free survival was better in patients with >100-fold PRAME expression (86% vs. 74%; p=0.03), and this cut-off established two sub-groups with different relapse-free survival rates among patients with a white cell count <10(9)/L (5-year relapse-free survival 94% vs. 80%, p=0.01). This effect was similar in patients with a white cell count >10(9)/L, although differences were not statistically significant. In multivariate analysis, white cell count >10(9)/L (p<0.001), bone marrow blasts >90% (p=0.001), and PRAME expression <100-fold (p=0.009) were associated with short relapse-free survival. Samples at remission showed PRAME levels similar to those in normal controls while samples at relapse over-expressed PRAME again. Furthermore, 12/13 samples collected within the 6-month period preceding relapse showed a >10-fold increase in PRAME expression levels. Low PRAME expression defines a subgroup of patients with acute promyelocytic leukemia with a short relapse-free survival. This marker could be useful as a secondary marker for monitoring patients with acute promyelocytic leukemia.Haematologica 09/2008; 93(12):1797-805. · 6.42 Impact Factor -
Article: The association of increased p14ARF/p16INK4a and p15INK4a gene expression with proliferative activity and the clinical course of multiple myeloma.
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ABSTRACT: p14/p16 and p15 gene expression was assessed by quantitative polymerase chain reaction in purified plasma cells (PC) from 52 patients with symptomatic multiple myeloma (MM) and seven with smoldering MM in order to clarify the impact of these genes on the proliferative activity of tumor cells and patients' outcome. p15 expression was lower in symptomatic MM than in smoldering SMM (-1.80 vs.1.51,p=0.026); similar results were observed for p14/p16. MM patients whose PC displayed high p15 and/or p14/p16 expression had a lower percentage of S-phase PC than the remaining cases (1.79%+/-1.35 vs. 3.04%+/-1.42, p=0.028), favorable prognostic factors and longer survival (100% vs. 49%at 2.5 years; p=0.007).Haematologica 12/2006; 91(11):1551-4. · 6.42 Impact Factor -
Article: Impact of BCR/ABL gene expression on the proliferative rate of different subpopulations of haematopoietic cells in chronic myeloid leukaemia.
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ABSTRACT: Despite the effects of BCR ABL on cell proliferation, no study has compared the proliferative rate of different haematopoietic cell compartments from chronic myeloid leukaemia (CML) with those of normal bone marrow (NBM). We comparatively analysed the cell cycle distribution and BCR/ABL expression in different compartments of BM cells from 15 CML and 11 NBM. Overall, our results showed similar proliferative indices in CML patients and NBM. However, CD34+ myeloid precursors from CML patients displayed an increased proportion of S + G2/M-phase cells (P = 0.04), while no significant differences were found between CML and NBM for other BM cell subsets analysed. In BM cells separated by fluorescence-activated cell sorting, decreasing levels of BCR/ABL mRNA were found from CD34+/CD38+ myeloid precursors to myeloblasts; BCR/ABL expression increased afterwards with a peak at the myelocyte/metamyelocyte stage, decreasing in the more mature band/neutrophil compartment. Unexpectedly, BCR/ABL gene expression showed an inverse correlation with the proportion of S + G2/M-phase cells (R = -0.33; P = 0.04). These results suggest that in CML, BCR/ABL expression is associated with an increased proliferation of CD34+ myeloid haematopoietic progenitor cells but not of other more mature myeloid precursors, as confirmed by the observation of an inverse correlation between the amount of BCR/ABL transcripts and the proportion of S + G2/M-phase cells.British Journal of Haematology 11/2006; 135(1):43-51. · 4.94 Impact Factor -
Article: Minimal residual disease monitoring in multiple myeloma: a comparison between allelic-specific oligonucleotide real-time quantitative polymerase chain reaction and flow cytometry.
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ABSTRACT: Minimal residual disease (MRD) studies are useful in multiple myeloma (MM). However, the definition of the best technique and clinical utility are still unresolved issues. The aim of this study was to analyze and compare the clinical utility of MRD studies in MM with two different techniques: allelic-specific oligonucleotide real-time quantitative PCR (ASO-RQ-PCR), and flow cytometry (FCM). Bone marrow samples from 32 MM patients who had achieved complete response after transplantation were evaluated by ASO-RQ-PCR, using TaqMan technology, and multiparametric FCM. ASO-RQ-PCR was only applicable in 75% of patients for a variety of technical reasons, while FCM was applicable in up to 90%. Therefore, simultaneous PCR/FCM analysis was possible in only 24 patients. The number of residual tumor cells identified by both techniques was very similar (mean=0.29%, range=0.001-1.61%, correlation coefficient=0.861). However, RQ-PCR was able to detect residual myelomatous cells in 17 patients while FCM only did so in 11; thus, 6 cases were FCM negative but PCR positive, all of them displaying a very low number of clonal cells (median=0.014%, range=0.001-0.11). Using an MRD threshold of 0.01% (10(-4)) two risk groups with significantly different progression-free survival could be identified by either PCR (34 vs. 15m, p=0.04) or FCM (27 vs. 10m, p=0.05). Although MRD evaluation by ASO-RQ-PCR is slightly more sensitive and specific than FCM, it is applicable in a lower proportion of MM patients and is more time-consuming, while both techniques provide similar prognostic information.Haematologica 11/2005; 90(10):1365-72. · 6.42 Impact Factor
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- Haematologica (4)
- British Journal of Haematology (1)
- Cytotherapy (1)
- European Journal Of Haematology (1)
- PLoS ONE (1)
Institutions
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2006
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Hospital Universitario de Salamanca
Salamanca, Castile and Leon, Spain
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2005
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Universidad de Salamanca
Salamanca, Castile and Leon, Spain
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