Deletions Of 6q15 Research Articles

6q deletion is frequent but unrelated to patient prognosis in breast cancer

BackgroundDeletions involving the long arm of chromosome 6 have been reported to occur in breast cancer, but little is known about the clinical relevance of this alteration.MethodsWe made use of a pre-existing tissue microarray with 2197 breast cancers and employed a 6q15/centromere 6 dual-labeling probe for fluorescence in situ (FISH) analysisResultsHeterozygous 6q15 deletions were found in 202 (18%) of 1099 interpretable cancers, including 19% of 804 cancers of no special type (NST), 3% of 29 lobular cancers, 7% of 41 cribriform cancers, and 28% of 18 cancers with papillary features. Homozygous deletions were not detected. In the largest subset of NST tumors, 6q15 deletions were significantly linked to advanced tumor stage and high grade (p < 0.0001 each). 6q deletions were also associated with estrogen receptor negativity (p = 0.0182), high Ki67 proliferation index (p < 0.0001), amplifications of HER2 (p = 0.0159), CCND1 (p = 0.0069), and cMYC (p = 0.0411), as well as deletions of PTEN (p = 0.0003), 8p21 (p < 0.0001), and 9p21 (p = 0.0179). However, 6q15 deletion was unrelated to patient survival in all cancers, in NST cancers, or in subsets of cancers defined by the presence or absence of lymph-node metastases.ConclusionOur data demonstrate that 6q deletion is a frequent event in breast cancer that is statistically linked to unfavorable tumor phenotype and features of genomic instability. The absence of any prognostic impact argues against a clinical applicability of 6q15 deletion testing in breast cancer patients.

MAP3K7 Is Recurrently Deleted in Pediatric T-Lymphoblastic Leukemia and Affects Cell Proliferation Independently of NF-κB

Deletions of 6q15-16.1 are recurrently found in pediatric T-cell acute lymphoblastic leukemia (T-ALL). This chromosomal region includes the mitogen-activated protein kinase kinase kinase 7 (MAP3K7) gene which is crucial for innate immune signaling. It is functionally and prognostically relevant both in hematologic malignancies and solid tumors. However, its distinct biological functions and relevance for different tumor entities are cell-type specific and remain controversial. Here, we show that MAP3K7 is recurrently deleted in pediatric T-ALL cases and that a residual expression of MAP3K7 is indispensable for T-ALL cell lines.We determined the frequency of MAP3K7 deletions in a cohort of 327 pediatric T-ALL patients by multiplex ligation-dependent probe amplification (MLPA). In a subgroup, we additionally employed targeted sequencing to identify point mutations. Deletions of MAP3K7 were identified in approximately 10% and point mutations in approximately 1% of children with T-ALL. All deletions of 6q15 were heterozygous and the adjacent CASP8AP2 gene was co-deleted in 32 of 33 cases. Clinically, the MAP3K7/CASP8AP2 deletions were significantly associated with a mature T-ALL immunophenotype, but not with any other patient characteristics or with the cumulative incidence of relapse and overall survival. Furthermore, deletions of MAP3K7/CASP8AP2 were preferentially associated with SIL-TAL1 fusions. Within the subgroup of SIL-TAL1 positive patients, those with MAP3K7/CASP8AP2 deletion showed a trend towards a higher risk of relapse compared to SIL-TAL1 -positive MAP3K7/CASP8AP2 -negative patients (25% vs 8%, p=0.13).We next analyzed the effects of shRNA-mediated MAP3K7 depletion on cell proliferation, apoptosis and NF-κB activation in three T-ALL cell lines (CCRF-CEM, Jurkat, MOLT4) that do not carry MAP3K7 deletions. We aimed at phenocopying a MAP3K7 deletion by using an Adeno-associated viral vector-mediated transduction system to efficiently deliver anti-MAP3K7 shRNA together with a GFP reporter to these cell lines. Transduction efficiency was above 80% for the cell lines CCRF-CEM and Jurkat. Depletion efficiency was uniformly in the range of 75%. Treatment with anti-MAP3K7 shRNA in comparison to non-silencing shRNA significantly slowed down proliferation in all three T-ALL cell lines and resulted in an increase of apoptotic cells up to 8-fold as measured by Annexin V staining.In order to assess the contribution of NF-κB signaling to the effects of MAP3K7 depletion, cells were treated with TNF-α and cell lysates analyzed for components of the NF-κB pathway by Western blotting and for expression of the NF-κB target genes BCL2, CMYC, FAS, PTEN and TNF-α by RT-PCR. Stimulation with TNF-α led to rapid and transient degradation of IκB and an accumulation of phospho-NF-κB p65 (Ser536), while other NF-κB proteins (p100, p105, p50) remained unaffected. Depletion of MAP3K7 neither changed IκB levels in unstimulated cells nor did it prevent the degradation of IκB after stimulation with TNF-α. Furthermore mRNA expression of none of the NF-κB target genes was consistently changed by more than 2-fold in any of the cell lines after MAP3K7 depletion. We conclude that in T-ALL cell lines, MAP3K7 is not required for the degradation of IκB and subsequent activation of NF-κB after stimulation with TNF-α.This study revealed that the recurrent deletion of MAP3K7/CASP8AP2 is associated with SIL-TAL1 fusions and a mature immunophenotype, but not with response to treatment and risk of relapse. Homozygous deletions of MAP3K7 were not observed, and efficient depletion of MAP3K7 interfered with viability of T-ALL cells, indicating that a residual expression of MAP3K7 is indispensable for T-lymphoblasts. DisclosuresSchrappe:Medac: Consultancy, Research Funding; Baxalta: Consultancy, Research Funding; JAZZ Pharma: Consultancy, Research Funding; SigmaTau: Consultancy, Research Funding; Novartis: Consultancy, Research Funding.

A nuclear shift of GSK3β protein is an independent prognostic factor in prostate cancer.

Glycogen synthase kinase 3ß (GSK3ß) regulates many cancer relevant cellular processes and represents a potential therapeutic target. GSK3ß overexpression has been linked to adverse tumor features in many cancers, but its role in prostate cancer remains uncertain. We employed immunohistochemical GSK3ß expression analysis on a tissue microarray with 12,427 prostate cancers. Cytoplasmic and nuclear GSK3ß staining was separately analyzed. GSK3ß staining was absent in normal prostate epithelium, whereas 57% of 9,164 interpretable cancers showed detectable GSK3ß expression. Cytoplasmic staining was considered weak, moderate, and strong in 36%, 19.5% and 1.5% of tumors and was accompanied by nuclear GSK3ß staining in 47% of cases. Cytoplasmic GSK3ß staining as well as nuclear GSK3ß accumulation was associated with advanced tumor stage, high Gleason grade, presence of lymph node metastasis and early biochemical recurrence (p < 0.0001 each for cytoplasmic staining and nu-clear accumulation). Prognosis of GSK3ß positive cancers became particularly poor if nuclear GSK3ß staining was also seen (p < 0.0001). The prognostic impact of nuclear GSK3ß accumu-lation was independent of established preoperative and postoperative parameters in multivari-ate analyses (p < 0.0001). The significant association of GSK3ß expression with deletions of PTEN, 3p13 (p < 0.0001 each), 5q21 (p = 0.0014) and 6q15 (p = 0.0026) suggest a role of GSK3ß in the development of genomic instability. In summary, the results of our study identify GSK3ß as an independent prognostic marker in prostate cancer.

5q21 deletion is often heterogeneous in prostate cancer.

Cancer heterogeneity represents a challenge for the analysis of prognostic molecular markers but can be used to study the evolution of molecular events in tumors. To assess the degree of heterogeneity of 5q21 deletions and their relationship with TMPRSS2:ERG status and 6q15 deletions in prostate cancer, a heterogeneity tissue microarray including 10 tissue spots from 10 different areas of 317 cancers was analyzed by fluorescence in situ hybridization for 5q21 deletion. Data on 6q and ERG were available from earlier studies. Deletions of 5q21 were found in 23% of 265 interpretable cancers and showed marked intratumoral heterogeneity. In the subset of 246 cancers with at least 3 interpretable spots, 23% had a 5q21 deletion. Heterogeneous 5q21 deletions were found in 71% and homogeneous in 29% of these cancers. The likelihood of 5q21 deletion was twice as high in ERG-negative (28%) than in ERG-positive cancers (16%, P = .024). In all 21 cases harboring both alterations, the tumor area containing a 5q21 deletion was smaller or equally large than the ERG-positive area but never larger. Deletions of 5q and 6q were significantly linked. However, the analysis of 32 tumors harboring both deletions did not suggest a specific order of appearance of these deletions. The 5q21 deletion preceded 6q15 in 10 tumors and 6q15 preceded 5q21 in 14 tumors. In summary, our study identifies 5q21 deletion as a highly heterogeneous aberration in prostate cancer that usually occurs late during cancer progression. This is a severe limitation for using 5q21 testing as a prognostic tool.

Up regulation and nuclear translocation of Y-box binding protein 1 (YB-1) is linked to poor prognosis in ERG-negative prostate cancer

Y-box binding protein 1 (YB-1) is an RNA and DNA binding factor with potential prognostic cancer. To evaluate the clinical impact of YB-1, a tissue microarray with 11,152 prostate cancers was analysed by immunohistochemistry. Cytoplasmic and nuclear staining was separately analysed. Cytoplasmic YB-1 was absent or weak in normal epithelium but seen in 86,3% of carcinomas. Cytoplasmic staining was weak, moderate, and strong in 29.6%, 43.7% and 13.0% of tumours and was accompanied by nuclear YB-1 staining in 32.1% of cases. Particularly nuclear staining was strongly linked to poor patient prognosis (p < 0.0001). YB-1 protein was more abundant in ERG positive (95.1%) than in ERG negative cancers (80.4%; p < 0.0001), but any prognostic impact of YB-1 staining was limited to the ERG-negative subset. Similarly, significant associations with pT stage and Gleason grade (p < 0.0001 each) were driven by the ERG negative subset. The significant association of YB-1 protein detection with deletions of PTEN, 5q21 and 6q15 fits well in the protein’s role as an inhibitor of DNA damage dependent cell cycle arrest, a role that is likely to induce genomic instability. In summary, the data show, that the prognostic impact of YB-1 expression is limited to ERG negative prostate cancers.

P16 upregulation is linked to poor prognosis in ERG negative prostate cancer

Altered expression of the p16 tumor suppressor is frequently found in prostate cancer, but its role for tumor development and patient prognosis is disputed. In order to clarify the prognostic role of p16 and to draw conclusions on interactions with key molecular features of prostate cancer, we studied p16 expression in a tissue microarray (TMA) with more than 12,400 prostate cancers and attached clinical, pathological, and molecular data such as ERG status and deletions of 3p13, 5q21, 6q15, and PTEN. p16 immunostaining was absent in non-neoplastic prostate cells but was found in 37% of 9627 interpretable prostate cancers. Finding p16 expression in 58% of ERG positive but in only 22% of ERG negative cancers (p<0.0001), highlights the known androgen-dependence of both genes. Significant associations between p16 upregulation and tumor phenotype or patient prognosis were strictly limited to the subset of ERG negative cancers. For example, p16 positivity increased from 15% in Gleason ≤3+3 to 38% in Gleason ≥4+4 cancers (p<0.0001) and was associated with early PSA recurrence (p<0.0001). p16 upregulation was strongly linked to deletions of PTEN (p<0.0001), highlighting the interaction of both genes in growth control. In conclusion, p16 upregulation is a strong prognostic factor in ERG negative cancers. The strict limitation of its prognostic impact to a molecularly defined subgroup challenges the concept of molecular prognosis testing without considering molecular subtypes.

The Combination of DNA Ploidy Status and PTEN/6q15 Deletions Provides Strong and Independent Prognostic Information in Prostate Cancer.

Aberrant DNA content has been discussed as a potential prognostic feature in prostate cancer. We analyzed the clinical significance of DNA ploidy in combination with prognostic relevant deletions of PTEN and 6q15 in 3,845 prostate cancers. The DNA status was diploid in 67.8%, tetraploid in 25.6%, and aneuploid in 6.8% of tumors, and deletions of PTEN and 6q15 occurred in 17.8% and 20.3% of tumors. Abnormal DNA content and deletions were linked to high Gleason score, advanced tumor stage, and positive nodal stage (P < 0.0001 each). The risk of PSA recurrence increased from diploid to tetraploid and from tetraploid to aneuploid DNA status (P < 0.0001 each). However, 40% of patients with Gleason score ≥4+4 and 55% of patients with PSA recurrence had diploid cancers. This fraction decreased to 21% (Gleason ≥4+4) and 29% (PSA recurrence) if PTEN and/or 6q deletion data were added to ploidy data to identify cancers with an aberrant DNA status. The significance of combining both deletions and ploidy was further demonstrated in a combined recurrence analysis. Presence of deletions increased the risk of PSA recurrence in diploid (P < 0.0001), tetraploid (P < 0.0001), and aneuploid cancers (P = 0.0049), and the combination of ploidy data and deletions provided clinically relevant information beyond the CAPRA-S nomogram. Multivariate modeling including preoperatively and postoperatively available parameters identified the "combined DNA status" as a strong independent predictor of poor patient outcome. The combinatorial DNA content analysis involving general (ploidy) and specific events (deletions) has the potential for clinical utility in prostate cancer. Clin Cancer Res; 22(11); 2802-11. ©2016 AACR.

Heterogeneity and chronology of 6q15 deletion and ERG-fusion in prostate cancer

Prostate cancer is notorious for its heterogeneity, which poses a problem for the applicability of diagnostic molecular markers. However, heterogeneity analysis can provide valuable information on the chronology in which molecular alterations arise. Here, we constructed a heterogeneity tissue microarray (TMA) comprising samples from 10 different tumor areas of 189 prostate cancers each in order to study the sequence of two frequent molecular alterations, i.e. 6q15 deletion and TMPRSS2:ERG fusion. Previous work shows a marked inverse relationship between these alterations, suggesting that presence of one of these alterations might impact development of the other. 6q15 deletion was analyzed by fluorescence in situ hybridization and ERG-expression by immunohistochemistry. Only 6.6% of 334 ERG-positive but 28.4% of 440 ERG-negative TMA spots showed 6q15 deletions (p < 0.0001). A breakdown of these data to the level of tumor foci revealed 6q deletions in 138 tumor foci that were large enough to have at least 3 analyzable TMA spots. These included 42 tumor foci with homogeneous ERG positivity and 16 with homogeneous 6q15 deletions. Remarkably, six of the 42 homogeneously ERG-positive tumor foci (14.3%) harbored small 6q15-deleted areas, but none of the 34 6q15-deleted foci showed areas of ERG positivity (p = 0.022). In conclusion, our data suggest that ERG-fusion can precede 6q15 deletion, but not vice versa. The complete absence of ERG-positive tumor areas in 6q15-deleted tumor foci further suggest that the functional consequences of 6q15 deletions may prevent the development of TMPRSS2:ERG fusions.

Cytoplasmic accumulation of ELAVL1 is an independent predictor of biochemical recurrence associated with genomic instability in prostate cancer.

ELAVL1 is an RNA binding protein involved in translation control, which might have a regulatory role in prostate cancer progress. To evaluate its impact and relationship with key genomic alterations, ELAVL1 expression was analyzed by immunohistochemistry on a tissue microarray containing 12,427 prostate cancers. The analysis revealed a mild to moderate predominantly nuclear immunostaining in normal prostate epithelium and an often higher both cytoplasmic and nuclear expression in cancer cells. Weak, moderate, and strong cytoplasmic ELAVL1 staining was found in 43%, 18%, and 3% of 10,478 interpretable tumors. Strong ELAVL1 staining was linked to high Gleason grade, advanced pathological tumor stage, positive nodal status, and PSA recurrence (P < 0.0001 each). A combined analysis of the effect of nuclear and cytoplasmic ELAVL1 expression on PSA recurrence revealed that the association with patient outcome was entirely driven by cytoplasmic staining. ELAVL1 positivity was more frequent in cancers harboring TMPRSS2:ERG fusions found by FISH (78%) or showing immunohistochemical ERG expression (74%) than in cancers without ERG rearrangement (63%) or ERG expression (58%, P < 0.0001 each). Strong cytoplasmic ELAVL1 staining was further linked to presence of PTEN, 5q21, 6q15, and 3p13 deletions (P < 0.0001 each), an observation consistent with cytoplasmic ELAVL1 accumulation in case of genomic instability. The prognostic role of ELAVL1 expression was independent of Gleason grade, T stage, N stage, surgical margin status, and preoperative PSA, irrespective of whether preoperative or postoperative variables were used for modeling. Our study identifies cytoplasmic accumulation of ELAVL1 as a predictor of adverse clinical behavior of prostate cancer independent of established clinico-pathological parameters.

Reduced AZGP1 expression is an independent predictor of early PSA recurrence and associated with ERG-fusion positive and PTEN deleted prostate cancers.

Zinc-alpha 2-glycoprotein (AZGP1) is involved in lipid metabolism and was suggested as a candidate prognostic biomarker in prostate cancer. To evaluate the clinical impact and relationship with key genomic alterations in prostate cancer, AZGP1 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancers. Data on ERG status and PTEN, 3p13, 5q21 and 6q15 deletions were available from earlier studies. AZGP1 expression was strong in benign prostatic glands but absent in 38.0% of 8,510 interpretable prostate cancers. Reduced AZGP1 expression was associated with TPMRSS2:ERG fusions, both by FISH and immunohistochemical analysis (p < 0.0001 each). For example, AZGP1 was absent in 54.6% of 2,029 ERG IHC positive but in only 28.1% of 2,398 ERG negative cancers. Irrespective of the ERG status, reduced AZGP1 expression was tightly linked to high Gleason score, advanced pathological tumor stage, positive nodal status and early PSA recurrence (p < 0.0001 each). Reduced AZGP1 expression was also strongly associated with PTEN deletions. AZGP1 immunostaining was lacking in 62.7% of 842 PTEN deleted but in only 37.3% of PTEN non-deleted cancers but retained strong prognostic influence in both subgroups (p < 0.0001 each). The prognostic role of AZGP1 expression was also independent of Gleason score, pT stage, pN stage, surgical margin status and preoperative PSA, irrespective of whether preoperative or postoperative variables were used for modeling. In conclusion, the results of our study demonstrate that reduced AZGP1 expression is strongly related to adverse prostate cancer prognosis, independently of established clinic-pathological variables and PTEN deletions.

Overexpression of enhancer of zeste homolog 2 (EZH2) characterizes an aggressive subset of prostate cancers and predicts patient prognosis independently from pre- and postoperatively assessed clinicopathological parameters.

Enhancer of zeste homolog 2 (EZH2) plays an important role in tumor development and progression by interacting with histone and nonhistone proteins. In the current study, we analyzed prevalence and prognostic impact of EZH2 in prostate cancer. EZH2 expression was analyzed by immunohistochemistry on a tissue microarray containing more than 12400 prostate cancer specimens. Results were compared to tumor phenotype, biochemical recurrence and molecular subtypes defined by ERG status as well as genomic deletions of 3p, 5q, 6q and PTEN. EZH2 immunostaining was detectable in 56.6% of 10168 interpretable cancers and considered strong in 1.1%, moderate in 12.2% and weak in 43.3% of cases. High EZH2 expression was strongly associated with high Gleason grade (P < 0.0001), advanced pathological tumor stage (P < 0.0001), positive nodal status (P < 0.0001), elevated preoperative PSA level (P = 0.0066), early PSA recurrence (P < 0.0001) and increased cell proliferation P < 0.0001). High-level EZH2 staining was also associated with TMPRSS2:ERG rearrangement and ERG expression in prostate cancers (P < 0.0001) and was linked to deletions of PTEN, 6q15, 5q21 and 3p13 (P < 0.0001 each) particularly in ERG-negative cancers. The prognostic impact of EZH2 was independent of established pre- and postoperatively assessed clinicopathological parameters. EZH2 has strong prognostic impact in prostate cancer and might contribute to the development of a fraction of genetically instable and particularly aggressive prostate cancers. EZH2 analysis might therefore be of clinical value for risk stratification of prostate cancer.

Cytoplasmic Accumulation of Sequestosome 1 (p62) Is a Predictor of Biochemical Recurrence, Rapid Tumor Cell Proliferation, and Genomic Instability in Prostate Cancer.

Sequestosome 1 (p62) is a multifunctional adapter protein accumulating in autophagy-defective cells. To evaluate the clinical impact and relationship with key genomic alterations in prostate cancer, p62 protein levels were analyzed by immunohistochemistry on a tissue microarray containing 12,427 prostate cancers. Data on ERG status and deletions of PTEN, 3p13, 5q21, and 6q15 were available from earlier studies. p62 immunostaining was absent in benign prostatic glands but present in 73% of 7,822 interpretable prostate cancers. Strong cytoplasmic p62 staining was tightly linked to high Gleason grade, advanced pathologic tumor (pT) stage, positive nodal status, positive resection margin, and early PSA recurrence (P < 0.0001 each). Increased levels of p62 were significantly linked to TMPRSS2-ERG fusions, both by FISH and immunohistochemical analysis (P < 0.0001 each). For example, moderate or strong p62 immunostaining was seen in 28.5% of cancers with TMPRSS2-ERG fusion detected by FISH and in 23.1% of cancers without such rearrangements (P < 0.0001). Strong p62 staining was significantly linked to the presence of all tested deletions, including PTEN (P < 0.0001), 6q15 (P < 0.0001), 5q21 (P = 0.0002), 3p13 (P = 0.0088), and 6q15 (P < 0.0001), suggesting a link between p62 accumulation and loss of genomic stability. The prognostic role of p62 protein accumulation was striking and independent of Gleason grade, pT stage, pN stage, surgical margin status, and preoperative PSA, regardless of whether preoperative or postoperative parameters were used for modeling. Our study identifies cytoplasmic accumulation of p62 as a strong predictor of an adverse prognostic behavior of prostate cancer independently from established clinicopathologic findings.

Abstract 4353: Improved prediction of prostate cancer prognosis by using a multiparametric molecular classifier

Abstract Background: Because no single molecular marker have proven to be sufficiently powerful for routine estimation of prostate cancer prognosis as to yet, it is hoped that the combined analysis of multiple markers will allow for distinguishing between indolent and aggressive forms of prostate cancer. In fact, first generation commercial multiparametric test assays show promising results. We hypothesized that such tests may be further optimized. Design: A tissue microarray (TMA) containing 0.6 mm tissue cores from more than 12,000 prostate cancer patients with long-term follow-up data was analyzed with more than 100 molecular markers by immunohistochemistry or FISH. Markers with strong and independent prognostic value in uni- and multivariate analyses were combined to obtain panels of markers that yield additional prognostic information beyond the standard parameters (including pre-operative PSA, Gleason grade, tumor stage, nodal stage) in ROC analysis. For this purpose, a simple score (0-10 points) was build based on the number and type of adverse features per tumor. Results: Markers with strong independent prognostic relevance included deletions of 6q15 and PTEN, overexpression of EZH2, TUBB3, and nuclear accumulation of p53, indicating dominant-negative TP53 gene mutation. A total of 5,129 cancers harbored none of these alterations (score 0) and showed the best prognosis in a Kaplan-Meier plot using biochemical recurrence as the study endpoint. The worst prognosis was found for 610 tumors harboring ≥8 (score 8-10) of these alterations, while an intermediate prognosis with decreasing time to recurrence was found for cancers with scores 1-2 (n = 2,418), 3-4 (n = 1,367) and 5-7 (n = 1038). The differences between the groups were high significant (p&amp;lt;0.0001). The 5 genes classifier provided prognostic information independent from PSA, Gleason, stage, and nodal stage (p&amp;lt;0.0001). Conclusion: Multiparametric classifiers have a high potential to improve the predictive accuracy of current models using established clinic-pathological models. Analyses of very large sets of patient tissues are instrumental to identify the best candidates for such molecular marker panels. It is likely, that continued analysis of our TMA will identify even better marker panels than the current 5 genes classifier. Citation Format: Maria Christina Tsourlakis, Martina Kluth, Thorsten Schlomm, Ronald Simon, Guido Sauter, Sarah Minner. Improved prediction of prostate cancer prognosis by using a multiparametric molecular classifier. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4353. doi:10.1158/1538-7445.AM2015-4353

High-Level HOOK3 Expression Is an Independent Predictor of Poor Prognosis Associated with Genomic Instability in Prostate Cancer.

Hook microtubule-tethering protein 3 (HOOK3) is an adaptor protein for microtubule-dependent intracellular vesicle and protein trafficking. In order to assess the role of HOOK3 in prostate cancer we analyzed HOOK3 expression by immunohistochemistry on a TMA containing more than 12,400 prostate cancers. Results were compared to tumor phenotype and PSA recurrence as well as aberrations possibly defining relevant molecular subtypes such as ERG status and deletions of 3p13, 5q21, 6q15 and PTEN. HOOK3 immunostaining was negative in normal luminal cells of prostate epithelium, whereas 53.3% of 10,572 interpretable cancers showed HOOK3 expression, which was considered low in 36.4% and high in 16.9% of cases. High-level HOOK3 expression was linked to advanced tumor stage, high Gleason score, high proliferation index, positive lymph node stage, and PSA recurrence (p<0.0001 each). The prognostic role of HOOK3 expression was independent of established clinico-pathological parameters both in preoperative and postoperative settings. Comparisons with molecular features were performed to draw conclusions on the potential function of HOOK3 in the prostate. A strong association with all examined deletions is consistent with a role of HOOK3 for maintaining genomic integrity by contributing to proper centrosome assembly. Finding HOOK3 expression in 74% of ERG positive but in only 38% of ERG negative cancers (p<0.0001) further suggests functional interactions between these genes. In conclusion, the results of our study identify HOOK3 as a strong candidate prognostic marker with a possible role in maintaining genomic integrity in prostate cancer, which may have potential for inclusion into clinical routine assays.

Loss of SOX9 Expression Is Associated with PSA Recurrence in ERG-Positive and PTEN Deleted Prostate Cancers.

The transcription factor SOX9 plays a crucial role in normal prostate development and has been suggested to drive prostate carcinogenesis in concert with PTEN inactivation. To evaluate the clinical impact of SOX9 and its relationship with key genomic alterations in prostate cancer, SOX9 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancers. Data on ERG status and deletions of PTEN, 3p13, 5q21 and 6q15 were available from earlier studies. SOX9 expression levels were comparable in luminal cells of normal prostate glands (50% SOX9 positive) and 3,671 cancers lacking TMPRSS2:ERG fusion (55% SOX9 positive), but was markedly increased in 3,116 ERG-fusion positive cancers (81% SOX9 positive, p<0.0001). While no unequivocal changes in the SOX9 expression levels were found in different stages of ERG-negative cancers, a gradual decrease of SOX9 paralleled progression to advanced stage, high Gleason grade, metastatic growth, and presence of PTEN deletions in ERG-positive cancers (p<0.0001 each). SOX9 levels were unrelated to deletions of 3p, 5q, and 6q. Down-regulation of SOX9 expression was particularly strongly associated with PSA recurrence in ERG-positive tumors harboring PTEN deletions (p=0.001), but had no significant effect in ERG-negative cancers or in tumors with normal PTEN copy numbers. In summary, the results of our study argue against a tumor-promoting role of SOX9 in prostate cancer, but demonstrate that loss of SOX9 expression characterizes a particularly aggressive subset of ERG positive cancers harboring PTEN deletions.

Abstract 2216: 6q15 deletion impede development of ERG fusion in prostate cancer

Abstract Deletions at chromosome 6q15 belong one to the most frequent alterations in pros-tate cancer, and are linked to poor prognosis. Furthermore, there is a marked inverse relationship between 6q15 deletions and TMPRSS2:ERG fusions in prostate cancer. While heterogeneity may limit the applicability of diagnostic molecular markers, it is important to estimate in vivo heterogeneity and the sequel of appearance of potential prognostic markers. In case of one alteration developing after the other, we would expect a small area of cancer having both alterations within a larger area having only one (the first appearing) of these changes. In this study, we used our heterogeneity tissue microarray approach as a surrogate method to determine in vivo heterogeneity of 6q15 deletions and TMPRSS2:ERG fusions. We constructed a heterogeneity TMA containing samples taken from 10 dif-ferent tumor containing tissue blocks of 189 prostate cancers. Each prostate con-tained 1 to 6 individual cancer foci allowing the molecular analysis of more than 350 tumor foci. 6q15 deletion was analyzed by fluorescence in situ hybridization and ERG expression by immunohistochemistry. Only 6.6% of 334 ERG positive but 28.4% of 440 ERG negative TMA spots showed 6q15 deletions (p&amp;lt;0.0001). A breakdown of these data to the level of tumor foci re-vealed 6q deletions in 34 tumor foci that were large enough to have at least 3 ana-lyzable TMA spots. The cohort included 42 tumor foci with a homogeneous ERG pos-itivity and 15 with a homogeneous 6q deletion. Remarkably, six of 42 homogeneously ERG positive tumor foci (14.3%) were focal 6q15-deleted, but none of 16 homogene-ous 6q15-deleted foci showed focal ERG positivity in the same tumor area (p=0.022). In conclusion of our study, the complete absence of ERG positive tumor foci in 6q15-deleted cancers suggests that the functional consequences of 6q15 deletions may prevent the development of TMPRSS2:ERG fusions. However, the development of 6q15 deletions is independent of the ERG status. Citation Format: Martina Kluth, Maria Christina Tsourlakis, David Meyer, Antje Krohn, Fabian Freudenthaler, Melanie Bauer, Georg Salomon, Hans Heinzer, Uwe Michl, Stefan Steurer, Ronald Simon, Guido Sauter, Thorsten Schlomm, Sarah Jane Pauline Minner. 6q15 deletion impede development of ERG fusion in prostate cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2216. doi:10.1158/1538-7445.AM2014-2216

Abstract 572: Reduced AZGP1 expression is an independent predictor of early PSA recurrence and associated with ERG fusion positive, PTEN deleted prostate cancers

Abstract Zinc-binding Alpha-2-Glycoprotein 1 (AZGP1) is a soluble protein that is known to stimulate lipid degradation in adipocytes. AZGP1 is physiologically expressed in various normal tissues including several types of secretory epithelial cells like breast cells, prostate cells and liver cells, and deregulated expression has been reported from several tumor types including breast, uterine cervix, and prostate cancers. In prostate cancer, AZGP1 was suggested as a candidate prognostic biomarker. To thoroughly evaluate the clinical impact of AZGP1 alteration in prostate cancer, we analyzed immunohistochemical AZGP1 expression in a tissue microarray containing 11,152 prostate cancers with attached clinical and molecular data. In addition, we estimated the relationship of AZGP1 expression with key genomic alterations in prostate cancer. For that purpose, we used data on ERG status and PTEN, 3p13, 5q21 and 6q15 deletions from our earlier studies. AZGP1 expression was strong in benign prostatic glands but absent in 38.0% of 8,510 interpretable prostate cancers. Reduced AZGP1 expression was associated with TMPRSS2:ERG fusion detected by FISH and immunohistochemical analysis (p&amp;lt;0.0001 each). For example, AZGP1 immunostaining was absent in 54.6% of 2,029 ERG positive but in only 28.1% of 2,398 ERG negative cancers (p&amp;lt;0.0001). Reduced expression of AZGP1 was tightly linked to high Gleason grade, advanced pathological tumor stage, positive nodal status and early PSA recurrence (p&amp;lt;0.0001) in all cancers, but also in the subgroups of ERG negative and ERG positive cancers. The prognostic role of AZGP1 expression was independent of Gleason grade, pT stage, pN stage, surgical margin status and preoperative PSA, irrespective of whether preoperative or postoperative parameters were used. Reduced AZGP1 expression was strongly associated with PTEN deletions - one of the strongest known molecular prognosticators in prostate cancer (p&amp;lt;0.0001). However, the association of reduced AZGP1 expression with early PSA recurrence was also independent of PTEN deletions. In conclusion, reduced expression of AZGP1 is strongly related to adverse prognostic features in prostate cancer - independent of clinico-pathological findings and PTEN deletions. Citation Format: Maria Christina Tsourlakis, Martina Kluth, Sandra Kleinhaus, Sawinee Masser, Christoph Burdelski, Hartwig Huland, Hans Heinzer, Markus Graefen, Burkhard Beyer, Stefan Steurer, Ronald Simon, Christina Koop, Thorsten Schlomm, Guido Sauter, Sarah Minner. Reduced AZGP1 expression is an independent predictor of early PSA recurrence and associated with ERG fusion positive, PTEN deleted prostate cancers. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 572. doi:10.1158/1538-7445.AM2014-572

NY-ESO-1 expression is tightly linked to TMPRSS2-ERG fusion in prostate cancer.

NY-ESO-1 has been suggested as therapeutic cancer vaccine in prostate cancer. This study was undertaken to explore the relationship of NY-ESO-1 with tumor phenotype, biochemical recurrence, and molecular subgroups in hormone-naive prostate cancers. NY-ESO-1 immunohistochemistry was analyzed on a tissue microarray containing 11,152 prostate cancer samples. Results were compared to clinically follow-up data, ERG status, and deletions on PTEN, 3p13, 5q21, and 6q15. NY-ESO-1 expression was absent in benign prostate glands. In prostate cancer, NY-ESO-1 positivity was found 8.8% of our 8,761 interpretable tumors including 5.8% with weak, 2.5% with moderate, and 0.5% with strong expression. There was a threefold higher rate of NY-ESO-1 expression in ERG fusion positive tumors than in ERG negative cancers (P < 0.0001). There was a significant association with early PSA recurrence, which was largely limited to ERG positive cancers. Within the ERG positive subgroup, high NY-ESO-1 expression was associated with early biochemical recurrence (P = 0.0002) and high Gleason grade (P < 0.0001). In ERG negative cancers, NY-ESO-1 expression was also linked to PTEN (P = 0.0012) and 6q15 deletions (P = 0.0005). Our observations indicate a tight link of NY-ESO-1 expression to ERG activation and (to a lesser extent) PTEN- and 6q15-deletions in prostate cancer. The impact of these interactions on the likelihood of response to immunotherapy is unclear. The prognostic impact of NY-ESO-1 expression is little and not independent of histologic variables.

The prognostic impact of high Nijmegen breakage syndrome (NBS1) gene expression in ERG-negative prostate cancers lacking PTEN deletion is driven by KPNA2 expression

The Nijmegen breakage syndrome (NBS1) gene was suggested as a prostate cancer susceptibility gene. This study was undertaken to determine, whether NBS1 expression is linked to clinically or molecularly relevant subgroups of prostate cancer. NBS1 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancer specimens. NBS1 expression was absent or only weakly detectable in benign prostate. In prostate cancers, NBS1 expression was found in 81.3% of interpretable tumors and was considered strong in 41.3% of cases. NBS1 upregulation was tightly linked to ERG-positive cancers (p<0.0001). Within ERG-negative cancers, strong NBS1 immunostaining was linked to advanced pathological tumor stage, high Gleason grade, and positive nodal status (p<0.0001 each), while high NBS1 immunostaining was only weakly associated with advanced pathological tumor stage in ERG-positive cancers (p=0.0099). A comparison with chromosomal deletions revealed a strong NBS1 upregulation in PTEN-deleted cancers, while deletions of 3p13, 5q21 and 6q15 did not affect NBS1 expression. High NBS1 expression was linked to biochemical recurrence in ERG-negative and PTEN non-deleted cancers (p<0.0001), which was largely driven by high KPNA2 karyopherin alpha 2 expression. In conclusion, our study identifies an association of NBS1 expression with surrogates of genomic instability in prostate cancer including TMPRSS2-ERG rearrangements and PTEN deletion. The prognostic impact of NBS1 expression in ERG-negative, PTEN non-deleted cancers was dependent of the expression status of its interaction partner KPNA2.

High nuclear karyopherin α 2 expression is a strong and independent predictor of biochemical recurrence in prostate cancer patients treated by radical prostatectomy

Increased levels of karyopherin α2 (KPNA2) expression have been described to be linked to poor prognosis in a variety of malignancies. This study was undertaken to evaluate the clinical impact of KPNA2 expression and its association with key genomic alterations in prostate cancers. A tissue microarray containing samples from 11 152 prostate cancers was analyzed for KPNA2 expression by immunohistochemistry. Results were compared with oncological follow-up data and genomic alterations such as TMPRSS2-ERG fusions and deletions of PTEN, 5q21, 6q15 or 3p13. KPNA2 expression was absent or weak in benign prostatic glands and was found to be in weak, moderate or strong intensities in 68.4% of 7964 interpretable prostate cancers. KPNA2 positivity was significantly linked to the presence of ERG rearrangement (P<0.0001). In ERG-negative and -positive prostate cancers, KPNA2 immunostaining was significantly associated with advanced pathological tumor stage (pT3b/pT4), high Gleason grade and early biochemical recurrence (P<0.0001 each). Multivariate analysis including all established prognostic criteria available after surgery revealed that the prognostic role of KPNA2 (P=0.001) was independent of high Gleason grade, advanced pathological tumor stage, high preoperative prostate-specific antigen level and positive surgical margin status (P<0.0001 each). The comparison of KPNA2 expression with deletions of PTEN, 5q21, 6q15 and 3p13 in ERG-positive and -negative cancers revealed a strong link to PTEN deletions in both subgroups (P<0.0001). In conclusion, the strong independent prognostic impact of KPNA2 expression raises the possibility that measurement of KPNA2 expression alone or in combination with other molecular parameters might possibly result in clinically useful information. The data also emphasize a critical role of the functionality of the nuclear import machinery for prostate cancer biology.