[Show abstract][Hide abstract] ABSTRACT: Epigenetic alterations are common in prostate cancer (PCa) and seem to contribute decisively to its initiation and progression. Moreover, aberrant promoter methylation is a promising biomarker for non-invasive screening. Herein, we sought to characterize EFEMP1 as biomarker for PCa, unveiling its biological relevance in prostate carcinogenesis. Microarray analyses of treated PCa cell lines and primary tissues enabled the selection of differentially methylated genes, among which EFEMP1 was further validated by MSP and bisulfite sequencing. Assessment of biomarker performance was accomplished by qMSP. Expression analysis of EFEMP1 and characterization of histone marks were performed in tissue samples and cancer cell lines to determine the impact of epigenetic mechanisms on EFEMP1 transcriptional regulation. Phenotypic assays, using transfected cell lines, permitted the evaluation of EFEMP1's role in PCa development. EFEMP1 methylation assay discriminated PCa from normal prostate tissue (NPT; P < 0.001, Kruskall–Wallis test) and renal and bladder cancers (96% sensitivity and 98% specificity). EFEMP1 transcription levels inversely correlated with promoter methylation and histone deacetylation, suggesting that both epigenetic mechanisms are involved in gene regulation. Phenotypic assays showed that EFEMP1 de novo expression reduces malignant phenotype of PCa cells. EFEMP1 promoter methylation is prevalent in PCa and accurately discriminates PCa from non-cancerous prostate tissues and other urological neoplasms. This epigenetic alteration occurs early in prostate carcinogenesis and, in association with histone deacetylation, progressively leads to gene down-regulation, fostering cell proliferation, invasion and evasion of apoptosis.
Journal of Cellular and Molecular Medicine 09/2014; · 4.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This work aimed to evaluate whether ETS transcription factors frequently involved in rearrangements in prostate carcinomas (PCa), namely ERG and ETV1, regulate specific or shared target genes. We performed differential ex-pression analysis on nine normal prostate tissues and 50 PCa enriched for different ETS rearrangements using exon-level expression microarrays, followed by in vitro validation using cell line models. We found specific deregulation of 57 genes in ERG-positive PCa and 15 genes in ETV1-positive PCa, whereas deregulation of 27 genes was shared in both tumor subtypes. We further showed that the expression of seven tumor-associated ERG target genes (PLA1A, CACNA1D, ATP8A2, HLA-DMB, PDE3B, TDRD1, and TMBIM1) and two tumor-associated ETV1 target genes (FKBP10 and GLYATL2) was significantly affected by specific ETS silencing in VCaP and LNCaP cell line models, respectively, whereas the expression of three candidate ERG and ETV1 shared targets (GRPR, KCNH8, and TMEM45B) was significantly affected by silencing of either ETS. Interestingly, we demonstrate that the expression of TDRD1, the topmost overexpressed gene of our list of ERG-specific candidate targets, is inversely correlated with the methylation levels of a CpG island found at −66 bp of the transcription start site in PCa and that TDRD1 expression is regulated by direct binding of ERG to the CpG island in VCaP cells. We conclude that ETS transcription factors regulate specific and shared target genes and that TDRD1, FKBP10, and GRPR are promising therapeutic targets and can serve as diagnostic markers for molecular subtypes of PCa harboring specific fusion gene rearrangements.
[Show abstract][Hide abstract] ABSTRACT: This work aimed to evaluate whether ETS transcription factors frequently involved in rearrangements in prostate carcinomas (PCa), namely ERG and ETV1, regulate specific or shared target genes. We performed differential expression analysis on nine normal prostate tissues and 50 PCa enriched for different ETS rearrangements using exon-level expression microarrays, followed by in vitro validation using cell line models. We found specific deregulation of 57 genes in ERG-positive PCa and 15 genes in ETV1-positive PCa, whereas deregulation of 27 genes was shared in both tumor subtypes. We further showed that the expression of seven tumor-associated ERG target genes (PLA1A, CACNA1D, ATP8A2, HLA-DMB, PDE3B, TDRD1, and TMBIM1) and two tumor-associated ETV1 target genes (FKBP10 and GLYATL2) was significantly affected by specific ETS silencing in VCaP and LNCaP cell line models, respectively, whereas the expression of three candidate ERG and ETV1 shared targets (GRPR, KCNH8, and TMEM45B) was significantly affected by silencing of either ETS. Interestingly, we demonstrate that the expression of TDRD1, the topmost overexpressed gene of our list of ERG-specific candidate targets, is inversely correlated with the methylation levels of a CpG island found at -66 bp of the transcription start site in PCa and that TDRD1 expression is regulated by direct binding of ERG to the CpG island in VCaP cells. We conclude that ETS transcription factors regulate specific and shared target genes and that TDRD1, FKBP10, and GRPR are promising therapeutic targets and can serve as diagnostic markers for molecular subtypes of PCa harboring specific fusion gene rearrangements.
Neoplasia (New York, N.Y.) 07/2012; 14(7):600-11. · 5.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: FLI1 and ERG, the major ETS transcription factors involved in rearrangements in the Ewing's sarcoma family of tumors (ESFT) and in prostate carcinomas (PCa), respectively, belong to the same subfamily, having 98% sequence identity in the DNA binding domain. We therefore decided to investigate whether the aberrant transcription factors in both malignancies have some common downstream targets. We crossed a publicly available list of all putative EWSR1-FLI1 target genes in ESFT with our microarray expression data on 24 PCa and 6 non-malignant prostate tissues (NPT) and choose four genes among the top-most differentially expressed between PCa with (PCa ERG+) and without (PCa ETS-) ETS fusion genes (HIST1H4L, KCNN2, ECRG4 and LDOC1), as well as four well-validated direct targets of the EWSR1-FLI1 chimeric protein in ESFT (NR0B1, CAV1, IGFBP3 and TGFBR2). Using quantitative expression analysis in 16 ESFT and seven alveolar rhabdomyosarcomas (ARMS), we were able to validate the four genes previously described as direct targets of the EWSR1-FLI1 oncoprotein, showing overexpression of CAV1 and NR0B1 and underexpression of IGFBP3 and TGFBR2 in ESFT as compared to ARMS. Although none of these four genes showed significant expression differences between PCa ERG+ and PCa ETS-, CAV1, IGFBP3 and TGFBR2 were less expressed in PCa in an independent series of 56 PCa and 15 NPT, as also observed for ECRG4 and LDOC1, suggesting a role in prostate carcinogenesis in general. On the other hand, we demonstrate for the first time that both HIST1H4L and KCNN2 are significantly overexpressed in PCa ERG+ and that ERG binds to the promoter of these genes. Conversely, KCNN2 was found underexpressed in ESFT relative to ARMS, suggesting that the EWSR1-ETS oncoprotein may have the opposite effect of ERG rearrangements in PCa. We conclude that aberrant ETS transcription factors modulate target genes differently in ESFT and PCa.
PLoS ONE 01/2012; 7(11):e49819. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To characterize the pattern of ETS rearrangements and to uncover novel ETS fusion genes, we analyzed 200 prostate carcinomas (PCa) with TaqMan low-density arrays (TLDAs), followed by selective analyses with fluorescence in situ hybridization (FISH), RT-PCR, and sequencing. Besides confirming the recurrent presence of ERG, ETV1, ETV4, and ETV5 rearrangements, we here report FLI1 as the fifth ETS transcription factor involved in fusion genes in prostate cancer. Outlier expression of the FLI1 gene was detected by TLDAs in one PCa that showed relative overexpression of FLI1 exons 4:5 as compared with FLI1 exons 2:3. A structural rearrangement was found using FISH probes flanking the FLI1 gene and RT-PCR and sequencing analyses showed fusion of SLC45A3 exon 1 with FLI1 exon 3. Interestingly, we found four cases with two different ETS rearrangements in the index tumor, thus revealing intratumor genetic heterogeneity. Correlation analysis with clinico-pathological data showed association of ERG rearrangements with locally advanced disease (pT3, P = 0.007) and MYC overexpression (P = 0.001), and association of ETV1 rearrangements with PTEN downregulation (P = 0.015). We report that FLI1 is a novel ETS transcription factor involved in gene fusions in prostate cancer and that intratumor genetic heterogeneity of ETS rearrangements can occasionally be found in index primary tumors.
Genes Chromosomes and Cancer 11/2011; 51(3):240-9. · 3.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Screening tools have greatly improved prostate cancer (PCa) detection, but the disease course is heterogeneous, and standard clinicopathological parameters do not fully discriminate aggressive from indolent tumors. To evaluate the prognostic value of the TMPRSS2-ERG fusion gene combined with chromosome arm 8q relative gain in diagnostic biopsies of PCa, we studied a consecutive series of 200 diagnostic needle biopsies from patients with 10-year disease-specific survival data. TMPRSS2-ERG fusion gene status and relative 8q gain were assessed by fluorescent in situ hybridization in whole formalin fixed paraffin-embedded biopsies. The TMPRSS2-ERG fusion gene was detected in 43.5% of PCa and was associated with lower Gleason score (P = 0.045), whereas relative 8q gain was present in 48% of PCa and was associated in high-Gleason score (P < 0.001). ERG rearrangement alone was not associated with clinical outcome, whereas relative 8q gain predicted worse disease-specific survival in PCa patients both with and without the TMPRSS2-ERG fusion gene (P < 0.001), independently of Gleason score, clinical stage, and treatment modality. We conclude that relative 8q gain in diagnostic needle biopsies is a poor prognostic factor independent of the TMPRSS2-ERG fusion gene status and of standard clinicopathological parameters.
Genes Chromosomes and Cancer 08/2011; 50(8):662-71. · 3.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The KRT19 gene encodes cytokeratin 19, an element of the cytoskeleton whose expression is frequently altered in renal cell carcinoma (RCC). Epigenetic phenomena, such as promoter methylation, may be a regulatory mechanism of expression of this gene. The aim of this study was to assess the epigenetic regulation of the KRT19 gene using epigenetic-modulating drugs, through the evaluation of methylation and expression status of the promoter region of KRT19 in 6 renal carcinoma cell lines and 112 primary renal tumors (52 clear cell RCC, 22 papillary RCC, 22 chromophobe cell RCC, and 16 oncocytomas). The diagnostic and prognostic value of KRT19 methylation levels in RCC was also evaluated. In cell lines 769-P, A498, and Caki-1, KRT19 re-expression was observed after treatment with 5-aza-2'deoxycytidine and trichostatin A. Conversely, a decrease in promoter methylation levels was apparent for the same cell lines. In primary renal tumors, KRT19 promoter methylation frequency was low (20.5% of cases). Although chromophobe cell RCC showed the lowest frequency compared with the remaining subtypes, this difference did not reach statistical significance. Moreover, no correlation between KRT19 methylation and expression was apparent in tumor samples and no significant correlations with clinicopathological parameters were observed. KRT19 methylation is not a frequent feature of primary RCC and oncocytomas, nor is it associated with clinicopathological parameters. Although we found evidence that KRT19 gene expression is epigenetically regulated in cell lines, this finding was not translated to primary tumors, suggesting the intervention of other genetic mechanisms for in vivo regulation of the KRT19 gene.
DNA and cell biology 02/2011; 30(2):85-90. · 2.28 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A large percentage of prostate cancers harbor TMPRSS2-ERG gene fusions, leading to aberrant overexpression of the transcription factor ERG. The target genes deregulated by this rearrangement, however, remain mostly unknown. To address this subject we performed genome-wide mRNA expression analysis on 6 non-malignant prostate samples and 24 prostate carcinomas with (n = 16) and without (n = 8) TMPRSS2-ERG fusion as determined by FISH. The top-most differentially expressed genes and their associations with ERG over-expression were technically validated by quantitative real-time PCR and biologically validated in an independent series of 200 prostate carcinomas. Several genes encoding metabolic enzymes or extracellular/transmembrane proteins involved in cell adhesion, matrix remodeling and signal transduction pathways were found to be co-expressed with ERG. Within those significantly over-expressed in fusion-positive carcinomas, CRISP3 showed more than a 50-fold increase when compared to fusion-negative carcinomas, whose expression levels were in turn similar to that of non-malignant samples. In the independent validation series, ERG and CRISP3 mRNA levels were strongly correlated (r(s) = 0.65, p<0.001) and both were associated with pT3 disease staging. Furthermore, immunohistochemistry results showed CRISP3 protein overexpression in 63% of the carcinomas and chromatin immunoprecipitation with an anti-ERG antibody showed that CRISP3 is a direct target of the transcription factor ERG. We conclude that ERG rearrangement is associated with significant expression alterations in genes involved in critical cellular pathways that define a subset of locally advanced PCa. In particular, we show that CRISP3 is a direct target of ERG that is strongly overexpressed in PCa with the TMPRSS2-ERG fusion gene.
PLoS ONE 01/2011; 6(7):e22317. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The OPCML gene (opioid binding protein/cell adhesion molecule-like), a putative tumour suppressor gene, is frequently inactivated in carcinomas, namely through aberrant promoter methylation. Herein, we aimed to determine whether OPCML altered expression mediated by epigenetic mechanisms was implicated in bladder carcinogenesis and to assess its potential as a bladder cancer epi-marker. OPCML promoter methylation levels from 91 samples of bladder urothelial carcinoma, 25 normal bladder tissues and bladder cancer cell lines were assessed by quantitative methylation-specific polymerase chain reaction, and correlated with OPCML mRNA expression, determined by quantitative reverse-transcription polymerase chain reaction. To prove the epigenetic regulation of OPCML, five bladder cancer cell lines were exposed to 5-aza-2'deoxycytidine (5-aza-dC), a specific DNA methyltransferase inhibitor and trichostatin A (TSA), a histone deacetylase inhibitor. In bladder tumours, the overall frequency of methylation was 60% and methylation levels were significantly higher when compared with normal mucosa (P=0.0001). No correlation was found between methylation levels and clinicopathological parameters. Interestingly, OPCML promoter methylation was associated with worse disease-specific survival (P=0.022) in univariate analysis. Furthermore, a significant inverse correlation between OPCML promoter methylation and mRNA expression levels was found, although a significant re-expression was only achieved when 5-aza-dC and TSA were used simultaneously. The high frequency of OPCML promoter methylation in urothelial carcinomas suggests an important role for this epigenetic alteration in bladder carcinogenesis, highlighting its potential as an epigenetic biomarker for bladder urothelial carcinoma with prognostic significance.
European journal of cancer (Oxford, England: 1990) 01/2011; 47(7):1106-14. · 4.12 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The association of a genetic analysis that could improve the diagnostic accuracy of renal cell tumors in biopsy samples would allow better-informed therapeutic decisions. We performed comparative genomic hybridization (CGH) on an ex vivo fine-needle aspiration (FNA) biopsy and a tumor fragment obtained from 75 patients consecutively diagnosed with renal tumors and subjected to radical nephrectomy. The pattern of genomic changes by CGH was used blindly to classify the renal tumors and the genetic findings were subsequently compared with the histopathologic diagnosis. In particular cases, including in two carcinomas with morphologically distinct tumor areas, we performed FISH with several locus-specific probes, and looked for VHL point mutations, exonic rearrangements, or promoter methylation. CGH was successful in 82.7% FNA biopsies and in 96% tumor fragments, with the former allowing genetic diagnosis in 75% of renal cell tumors. The genetic and the initial histological classification differed in two renal neoplasias, but the genetic diagnosis was confirmed after review. The genetic pattern correctly diagnosed 93.5% of clear cell renal cell carcinomas (RCC), 61.5% of chromophobe RCC, 100% of papillary RCC, and 14.3% of oncocytomas, with the negative predictive value being 93.9, 90.7, 100, and 90.2%, respectively. The positive predictive value and specificity of copy number profiles was 100%. We demonstrate that genetic diagnosis by CGH on FNA biopsies can improve differential diagnosis in patients with kidney tumors.
Genes Chromosomes and Cancer 10/2010; 49(10):935-47. · 3.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Constitutive activation of the Wnt signaling pathway is a common feature of solid tumors and contributes to uncontrolled cell-growth and impaired differentiation. We hypothesized that gene silencing mediated through aberrant promoter methylation of upstream Wnt antagonist genes might result in beta-catenin accumulation, resulting in constitutive Wnt activation. Wnt antagonist genes (SFRP1, WIF1, APC and CDH1) and CTNNB1 promoter methylation was examined in genomic DNA extracted from 12 urological cancer cell lines and correlated with CTNNB1 mRNA expression. Promoter methylation status was then assessed in 36 BCa, 30 PCa, 31 RCT, and normal bladder mucosa (15), prostate (10) and renal (5) tissue samples. Finally, CTNNB1 mRNA relative expression levels were correlated with Wnt antagonist gene methylation status in RCT. Methylation was found in at least one Wnt antagonist gene and the CTNNB1 promoter was unmethylated in all cancer cell lines tested. When gene methylation levels were compared between cancer cell lines with high and low CTNNB1 mRNA expression, a trend was found for increased CDH1 promoter methylation levels in the former. BCa and PC a tumors demonstrated high frequency of promoter methylation at all tested genes. In RCT, CTNNB1 was unmethylated in all cases and the overall frequency of promoter methylation at the remainder genes was lower. Interestingly, median CTNNB1 mRNA expression levels were significantly higher in RCTs methylated in at least one Wnt antagonist gene promoter. We concluded that epigenetic deregulation of Wnt pathway inhibitors may contribute to aberrant activation of Wnt signaling pathway in bladder, prostate and renal tumors.
Epigenetics: official journal of the DNA Methylation Society 05/2010; 5(4):343-51. · 4.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Apoptosis is known to be involved in tumorigenesis and a defective ratio between cell proliferation and apoptosis may contribute to the emergence of a malignant phenotype. Transcriptional silencing of apoptosis-related genes associated with aberrant promoter methylation may impair the apoptotic machinery, ultimately leading to cancer development. Aberrant promoter methylation of numerous genes involved in many different pathways is frequent in prostate cancer. Our aim was to quantitatively assess the methylation status of several apoptosis-related genes in prostate adenocarcinoma (PCa) and its precursor lesion, high-grade prostatic intraepithelial neoplasia (HGPIN). First, 120 PCa and 39 HGPIN were screened for altered expression of BCL2, CASP8, CASP3, DAPK DR3, DR4, DR6, FAS, TMS1, TNFR2, using 28 benign prostate hyperplasias and 10 normal prostates as controls. Underexpressed genes were then assessed by quantitative methylation-specific PCR to determine the promoter methylation status. Finally, quantitative mRNA expression of aberrantly methylated genes was performed and methylation data was correlated with standard clinicopathologic parameters. DAPK, DR4 and TNFR2 were significantly overexpressed in HGPIN and PCa, whereas BCL2, TMS1, and FAS were downregulated. Although methylation levels were significantly higher for TMS1 and BCL2 (correlating with advanced stage), an inverse correlation with mRNA expression was found only for BCL2. We concluded that the apoptotic pathways are largely preserved in prostate carcinogenesis, in particular the extrinsic pathway, with the exception of FAS and TMS1, which are epigenetically downregulated. In addition, BCL2 was also found to be frequently silenced in PCa due to aberrant promoter methylation, thus supporting a future role for apoptosis-targeted therapy in prostate cancer.
[Show abstract][Hide abstract] ABSTRACT: The purpose of this study was to identify genetic aberrations contributing to clinical aggressiveness of malignant peripheral nerve sheath tumors (MPNSTs).
Samples from 48 MPNSTs and 10 neurofibromas were collected from 51 patients with (n = 31) or without (n = 20) neurofibromatosis type 1 (NF1). Genome-wide DNA copy number changes were assessed by chromosomal and array-based comparative genomic hybridization (CGH) and examined for prognostic significance. For a subset of 20 samples, RNA microarray data were integrated with the genome data to identify potential target genes.
Forty-four (92%) MPNSTs displayed DNA copy number changes (median, 18 changes per tumor; range, 2 to 35 changes). Known frequent chromosomal gains at chromosome arms 8q (69%), 17q (67%), and 7p (52%) and losses from 9p (50%), 11q (48%), and 17p (44%) were confirmed. Additionally, gains at 16p or losses from 10q or Xq identified a high-risk group with only 11% 10-year disease-specific survival (P = .00005). Multivariate analyses including NF1 status, tumor location, size, grade, sex, complete remission, and initial metastatic status showed that the genomic high-risk group was the most significant predictor of poor survival. Several genes whose expression was affected by the DNA copy number aberrations were identified.
The presence of specific genetic aberrations was strongly associated with poor survival independent of known clinical risk factors. Conversely, within the total patient cohort with 34% 10-year disease-specific survival, a low-risk group was identified: without changes at chromosomes 10q, 16p, or Xq in their MPNSTs, the patients had 74% 10-year survival.
Journal of Clinical Oncology 02/2010; 28(9):1573-82. · 18.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oncogenic point mutations in KIT or PDGFRA are recognized as the primary events responsible for the pathogenesis of most gastrointestinal stromal tumors (GIST), but additional genomic alterations are frequent and presumably required for tumor progression. The relative contribution of such alterations for the biology and clinical behavior of GIST, however, remains elusive.
In the present study, somatic mutations in KIT and PDGFRA were evaluated by direct sequencing analysis in a consecutive series of 80 GIST patients. For a subset of 29 tumors, comparative genomic hybridization was additionally used to screen for chromosome copy number aberrations. Genotype and genomic findings were cross-tabulated and compared with available clinical and follow-up data.
We report an overall mutation frequency of 87.5%, with 76.25% of the tumors showing alterations in KIT and 11.25% in PDGFRA. Secondary KIT mutations were additionally found in two of four samples obtained after imatinib treatment. Chromosomal imbalances were detected in 25 out of 29 tumors (86%), namely losses at 14q (88% of abnormal cases), 22q (44%), 1p (44%), and 15q (36%), and gains at 1q (16%) and 12q (20%). In addition to clinico-pathological high-risk groups, patients with KIT mutations, genomic complexity, genomic gains and deletions at either 1p or 22q showed a significantly shorter disease-free survival. Furthermore, genomic complexity was the best predictor of disease progression in multivariate analysis.
In addition to KIT/PDGFRA mutational status, our findings indicate that secondary chromosomal changes contribute significantly to tumor development and progression of GIST and that genomic complexity carries independent prognostic value that complements clinico-pathological and genotype information.
[Show abstract][Hide abstract] ABSTRACT: Septins are proteins associated with crucial steps in cell division and cellular integrity. In humans, 14 septin genes have been identified, of which five (SEPT2, SEPT5, SEPT6, SEPT9, and SEPT11) are known to participate in reciprocal translocations with the MLL gene in myeloid neoplasias. We have recently shown a significant down-regulation of both SEPT2 and MLL in myeloid neoplasias with the MLL-SEPT2 fusion gene. In this study, we examined the expression pattern of the other 13 known septin genes in altogether 67 cases of myeloid neoplasia, including three patients with the MLL-SEPT2 fusion gene, four with MLL-SEPT6 fusion, and three patients with the MLL-SEPT9 fusion gene. When compared with normal controls, a statistically significant down-regulation was observed for the expression of both MLL (6.4-fold; p=0.008) and SEPT6 (1.7-fold; p=0.002) in MLL-SEPT6 leukemia. Significant down-regulation of MLL was also found in MLL-MLLT3 leukemias. In addition, there was a trend for SEPT9 down-regulation in MLL-SEPT9 leukemias (4.6-fold; p=0.077). Using hierarchical clustering analysis to compare acute myeloid leukemia genetic subgroups based on their similarity of septin expression changes, we found that MLL-SEPT2 and MLL-SEPT6 neoplasias cluster together apart from the remaining subgroups and that PML-RARA leukemia presents under-expression of most septin family genes.
Leukemia research 09/2009; 34(5):615-21. · 2.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A relevant role of septins in leukemogenesis has been uncovered by their involvement as fusion partners in MLL-related leukemia. Recently, we have established the MLL-SEPT2 gene fusion as the molecular abnormality subjacent to the translocation t(2;11)(q37;q23) in therapy-related acute myeloid leukemia. In this work we quantified MLL and SEPT2 gene expression in 58 acute myeloid leukemia patients selected to represent the major AML genetic subgroups, as well as in all three cases of MLL-SEPT2-associated myeloid neoplasms so far described in the literature.
Cytogenetics, fluorescence in situ hybridization (FISH) and molecular studies (RT-PCR, qRT-PCR and qMSP) were used to characterize 58 acute myeloid leukemia patients (AML) at diagnosis selected to represent the major AML genetic subgroups: CBFB-MYH11 (n = 13), PML-RARA (n = 12); RUNX1-RUNX1T1 (n = 12), normal karyotype (n = 11), and MLL gene fusions other than MLL-SEPT2 (n = 10). We also studied all three MLL-SEPT2 myeloid neoplasia cases reported in the literature, namely two AML patients and a t-MDS patient.
When compared with normal controls, we found a 12.8-fold reduction of wild-type SEPT2 and MLL-SEPT2 combined expression in cases with the MLL-SEPT2 gene fusion (p = 0.007), which is accompanied by a 12.4-fold down-regulation of wild-type MLL and MLL-SEPT2 combined expression (p = 0.028). The down-regulation of SEPT2 in MLL-SEPT2 myeloid neoplasias was statistically significant when compared with all other leukemia genetic subgroups (including those with other MLL gene fusions). In addition, MLL expression was also down-regulated in the group of MLL fusions other than MLL-SEPT2, when compared with the normal control group (p = 0.023)
We found a significant down-regulation of both SEPT2 and MLL in MLL-SEPT2 myeloid neoplasias. In addition, we also found that MLL is under-expressed in AML patients with MLL fusions other than MLL-SEPT2.