Chromosome 5 harbors two independent deletion hotspots at 5q13 and 5q21 that characterize biologically different subsets of aggressive prostate cancer.

Deletion of chromosome 5q is common in prostate cancer and is linked to aggressive disease. Most previous studies focused on 5q21 where CHD1 is located, but deletion of mapping studies has identified a second deletion hotspot at 5q13. To clarify the prevalence and clinical relevance of 5q13 deletions and to determine the relative importance of 5q13 and 5q21 abnormalities, a tissue microarray containing samples from 12 427 prostate cancers was analyzed by fluorescence in situ hybridization. Deletion of 5q13 and 5q21 was found in 13.5% and 10%, respectively, of 7932 successfully analyzed cancers. Deletion was restricted to 5q13 in 49.4% and to 5q21 in 32.0% of cancers with a 5q deletion. Only 18.6% of 5q-deleted cancers had deletions of both loci. Both 5q13 and 5q21 deletions were significantly linked to advanced tumor stage, high Gleason grade, nodal metastasis and early biochemical recurrence (P < .005 each). Cancers with co-deletion of 5q13 and 5q21 had a worse prognosis than cancers with isolated 5q13 or 5q21 deletion (P = .0080). Comparison with TMPRSS2:ERG fusion status revealed that 5q21 deletions were tightly linked to ERG negativity (P < .0001) while 5q13 deletions were unrelated to the ERG status. In summary, 5q13 deletion and 5q21 deletion are common, but independent genomic alterations with different functional effects lead to aggressive prostate cancer.

Upregulation of the transcription factor TFAP2D is associated with aggressive tumor phenotype in prostate cancer lacking the TMPRSS2:ERG fusion.

BACKGROUND: TFAP2D is a transcription factor important for modulating gene expression in embryogenesis. Its expression and prognostic role in prostate cancer has not been evaluated. METHODS: Therefore, a tissue microarray containing 17,747 prostate cancer specimens with associated pathological, clinical, and molecular data was analyzed by immunohistochemistry to assess the role of TFAP2D. RESULTS: TFAP2D expression was typically increased in prostate cancer as compared to adjacent non-neoplastic glands. TFAP2D staining was considered negative in 24.3% and positive in 75.7% of 13,545 interpretable cancers. TFAP2D staining was significantly linked to advanced tumor stage, high classical and quantitative Gleason grade, lymph node metastasis, and a positive surgical margin (p ≤ 0.0045). TFAP2D positivity was more common in ERG fusion positive (88.7%) than in ERG negative cancers (66.8%; p < 0.0001). Subset analyses in 3776 cancers with and 4722 cancers without TMPRSS2:ERG fusion revealed that associations with tumor phenotype and patient outcome were largely driven by the subset of ERG negative tumors. Multivariate analysis did not identify TFAP2D protein expression levels as a robust independent prognostic parameter. Positive TFAP2D immunostaining was significantly associated with 10 of 11 previously analyzed chromosomal deletions in ERG negative cancers (p ≤ 0.0244 each) indicating that elevated TFAP2D expression parallels genomic instability in prostate cancer. CONCLUSION: These data demonstrate that TFAP2D protein overexpression is linked to prostate cancer progression and genomic instability in ERG negative prostate cancers.

Epithelial splicing regulatory protein 1 and 2 (ESRP1 and ESRP2) upregulation predicts poor prognosis in prostate cancer.

BACKGROUND: Epithelial splicing regulatory protein 1 (ESRP1) and 2 (ESRP2) regulate alternative splicing events of various pre-mRNAs. Some of these targets play a role in cancer-associated processes, including cytoskeleton reorganization and DNA-repair processes. This study was undertaken to estimate the impact of ESRP1 and ESRP2 alterations on prostate cancer patient prognosis. METHODS: A tissue microarray made from 17,747 individual cancer samples with comprehensive, pathological, clinical and molecular data was analyzed by immunohistochemistry for ESRP1 and ESRP2. RESULTS: Nuclear staining for ESRP1 was seen in 38.6% (36.0% low, 2.6% high) of 12,140 interpretable cancers and in 41.9% (36.4% low, 5.3% high) of 12,962 interpretable cancers for ESRP2. Nuclear protein expression was linked to advanced tumor stage, high Gleason score, presence of lymph node metastasis, early biochemical recurrence, and ERG-positive cancers (p < 0.0001 each). Expression of ESRPs was significantly linked to 11 (ESRP1)/9 (ESRP2) of 11 analyzed deletions in all cancers and to 8 (ESRP1)/9 (ESRP2) of 11 deletions in ERG-negative cancers portending a link to genomic instability. Combined ESRPs expression analysis suggested an additive effect and showed the worst prognosis for cancers with high ESRP1 and ESRP2 expression. Multivariate analyses revealed that the prognostic impact of ESRP1, ESRP2 and combined ESRP1/ESRP2 expression was independent of all established pre- and postoperative prognostic features. CONCLUSIONS: Our data show a striking link between nuclear ESRP expression and adverse features in prostate cancer and identifies expression of ESRP1 and/or ESRP2 as independent prognostic markers with a potential for routine application.

Claudin-1 upregulation is associated with favorable tumor features and a reduced risk for biochemical recurrence in ERG-positive prostate cancer.

BACKGROUND: Claudin-1 is a membrane-tight junction protein and important for the sealing of the paracellular cleft in epithelial and endothelial cells. Differential expression of Claudin-1 is linked to disease outcome in various cancers. MATERIAL AND METHODS: To evaluate the potential relevance of Claudin-1 expression in prostate cancer, a tissue microarray containing samples of 17,747 tumors with annotated clinico-pathological and molecular data was immunohistochemically analyzed for Claudin-1 expression. RESULTS: In normal prostate, glandular cells were always Claudin-1-negative while there was a strong staining of gland-surrounding basal cells. In contrast to normal prostatic glands, a positive Claudin-1 immunostaining, was found, however, in 38.7% of 12,441 interpretable cancers and was considered weak in 12.7%, moderate in 13.2%, and strong in 12.8% of cases. Positive Claudin-1 immunostaining was associated with favorable tumor features like low pT (p = 0.0032), low Gleason grade (p< 0.0001), and a reduced risk of PSA recurrence (p = 0.0005). A positive Claudin-1 staining was markedly more frequent in ERG-positive (63%) than in ERG-negative cancers (23%; p < 0.0001). Subset analyses revealed that all associations of Claudin-1 expression and favorable phenotype and prognosis were driven by ERG-positive cancers. Multivariate analyses revealed, however, that even in ERG-positive cancers, the prognostic impact of high Claudin-1 expression was not independent of established clinico-pathological parameters. Comparison with 12 previously analyzed chromosomal deletions identified conspicuous associations with PTEN and 12p13 deletions potentially indicating functional interactions. CONCLUSION: These data identify a peculiar role for Claudin-1 in prostate cancer. The protein is overexpressed in a fraction of prostate cancers and increased Claudin-1 expression levels predict a favorable prognosis in ERG-positive cancer.

Upregulation of PTTG1 is associated with poor prognosis in prostate cancer.

Pituitary tumor-transforming gene 1 (PTTG1) is a regulator of chromosome stability. PTTG1 overexpression had been associated with tumor aggressiveness in several cancer types. To examine its prognostic utility in prostate cancer, a tissue microarray including 12 427 tumors with clinical and molecular data was analyzed by immunohistochemistry. PTTG1 immunostaining was largely absent in normal prostate epithelial cells. In cancers, staining was considered weak in 5.4%, moderate in 5.6% and strong in 0.8%. Strong staining was linked to advanced pT stage, high classical and quantitative Gleason grade, high Ki67-labeling index (all P < 0.0001) and lymph node metastasis (P = 0.0083). The prognostic impact of PTTG1 expression was independent of established preoperative and postoperative prognostic features. Comparison with molecular features revealed that PTTG1 upregulation was associated with nine of 12 common genomic deletions (P < 0.05), p53 alterations and high androgen receptor levels (P < 0.001 each), but was unrelated to the TMPRSS2:ERG fusion status. In conclusion, these data identify PTTG1 as a strong and independent prognostic feature in prostate cancer. PTTG1 measurement, either alone or in combination with other biomarkers might be instrumental for determining prostate cancer aggressiveness.

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.

Loss of CCAAT-enhancer-binding protein alpha (CEBPA) is linked to poor prognosis in PTEN deleted and TMPRSS2:ERG fusion type prostate cancers.

BACKGROUND: The transcription factor CCAAT-enhancer-binding protein alpha (CEBPA) is a crucial regulator of cell proliferation and differentiation. Expression levels of CEBPA have been suggested to be prognostic in various tumor types. METHODS: Here, we analyzed the immunohistochemical expression of CEBPA in a tissue microarray containing more than 17 000 prostate cancer specimens with annotated clinical and molecular data including for example TMPRSS2:ERG fusion and PTEN deletion status. RESULTS: Normal prostate glands showed moderate to strong CEBPA staining, while CEBPA expression was frequently reduced (40%) or lost (30%) in prostate cancers. Absence of detectable CEBPA expression was markedly more frequent in ERG negative (45%) as compared to ERG positive cancers (20%, P < 0.0001). Reduced CEBPA expression was linked to unfavorable phenotype (P < 0.0001) and poor prognosis (P = 0.0008). Subgroup analyses revealed, that the prognostic value of CEBPA loss was entirely driven by tumors carrying both TMPRSS2:ERG fusions and PTEN deletions. In this subgroup, CEBPA loss was tightly linked to advanced tumor stage (P < 0.0001), high Gleason grade (P < 0.0001), positive nodal stage (0.0003), and early biochemical recurrence (P = 0.0007), while these associations were absent or markedly diminished in tumors with normal PTEN copy numbers and/or absence of ERG fusion. CONCLUSIONS: CEBPA is down regulated in about one third of prostate cancers, but the clinical impact of CEBPA loss is strictly limited to the subset of about 10% prostate cancers carrying both ERG fusion and deletions of the PTEN tumor suppressor. Our findings challenge the concept that prognostic molecular markers may be generally applicable to all prostate cancers.

The independent prognostic impact of the GATA2 pioneering factor is restricted to ERG-negative prostate cancer.

GATA2 is a pioneering transcription factor governing androgen receptor expression and signaling in prostate cells. To understand the prognostic potential of GATA2 assessment in prostate cancer, we analyzed nuclear GATA2 expression on an annotated tissue microarray with 12,427 prostate cancer samples. Normal prostate glands were negative to weakly positive. GATA2 staining was found in almost all prostate cancers (95%). Strong GATA2 staining was linked to advanced tumor stage, high classical and quantitative Gleason grade (p < 0.0001 each), positive nodal stage (p = 0.0116), and early biochemical recurrence (p < 0.0001). GATA2 was linked to ERG-fusion-type cancers, with strong GATA2 staining in 29% of ERG-negative and 53% of ERG-positive cancers (p < 0.0001). Separate calculations in 3854 cancers with and 4768 cancers without TMPRSS2:ERG fusion revealed that these associations with tumor phenotype and patient outcome were largely driven by the subset of ERG-negative tumors. GATA2 expression was further linked to androgen receptor expression: Only 8% of androgen receptor-negative, but 56% of strongly androgen receptor expressing cancers had strong GATA2 expression (p < 0.0001). In conclusion, the results of our study demonstrate that increasing GATA2 levels are linked to prostate cancer progression and aggressiveness. The prognostic value of GATA2 is remarkable in ERG-negative cancers. However, the upregulation of GATA2 in ERG-positive cancers makes it unsuitable as a prognostic marker in this patient subset.

High-level expression of protein tyrosine phosphatase non-receptor 12 is a strong and independent predictor of poor prognosis in prostate cancer.

BACKGROUND: Protein tyrosine phosphatase non-receptor 12 (PTPN12) is ubiquitously tyrosine phosphatase with tumor suppressive properties. METHODS: PTPN12 expression was analyzed by immunohistochemistry on a tissue microarray with 13,660 clinical prostate cancer specimens. RESULTS: PTPN12 staining was typically absent or weak in normal prostatic epithelium but seen in the majority of cancers, where staining was considered weak in 26.5%, moderate in 39.9%, and strong in 4.7%. High PTPN12 staining was associated with high pT category, high classical and quantitative Gleason grade, lymph node metastasis, positive surgical margin, high Ki67 labeling index and early prostate specific antigen recurrence (p < 0.0001 each). PTPN12 staining was seen in 86.4% of TMPRSS2:ERG fusion positive but in only 58.4% of ERG negative cancers. Subset analyses discovered that all associations with unfavorable phenotype and prognosis were markedly stronger in ERG positive than in ERG negative cancers but still retained in the latter group. Multivariate analyses revealed an independent prognostic impact of high PTPN12 expression in all cancers and in the ERG negative subgroup and to a lesser extent also in ERG positive cancers. Comparison with 12 previously analyzed chromosomal deletions revealed that high PTPN12 expression was significantly associated with 10 of 12 deletions in ERG negative and with 7 of 12 deletions in ERG positive cancers (p < 0.05 each) indicating that PTPN12 overexpression parallels increased genomic instability in prostate cancer. CONCLUSIONS: These data identify PTPN12 as an independent prognostic marker in prostate cancer. PTPN12 analysis, either alone or in combination with other biomarkers might be of clinical utility in assessing prostate cancer aggressiveness.

13q deletion is linked to an adverse phenotype and poor prognosis in prostate cancer.

Deletions of chromosome arm 13q belong to the most frequent molecular alterations in prostate cancer. To better understand the role of 13q deletion in prostate cancer we took advantage of our large prostate cancer tissue microarray comprising more than 12 000 cancer samples with full pathological and clinical follow-up data. Fluorescence in situ hybridization with probes for ENOX1 (13q14.11) and the retinoblastoma gene (RB1, 13q14.2) was employed. A 13q deletion was found in 21% of 7375 analyzable cancers. Deletions were always heterozygous and associated with high Gleason grade (P < .0001), advanced tumor stage (P < .0001), high preoperative prostate-specific antigen (PSA) levels (P = .0125), lymph node metastasis (P = .0377), positive resection margin (P = .0064), and early biochemical recurrence (P < .0001). 13q deletions were marginally more frequent in prostate cancers with negative ERG status (22.9%) than in ERG-positive tumors (18.7%; P < .0001). Loss of 13q predicted patient prognosis independently from established prognostic parameters that are available at the time of biopsy (P = .0004), including preoperative PSA level, clinical tumor stage, and biopsy Gleason grade. In summary, the results of our study identify 13q deletion as a frequent event in prostate cancer, which is linked to an adverse phenotype and poor prognosis in this disease.

High BCAR1 expression is associated with early PSA recurrence in ERG negative prostate cancer.

BACKGROUND: Breast cancer anti-estrogen resistance 1 (BCAR1/p130cas) is a hub for diverse oncogenic signaling cascades and promotes tumor development and progression. METHODS: To understand the effect of BCAR1 in prostate cancer, we analyzed its expression on more than 11,000 prostate cancer samples. BCAR1 expression levels were compared with clinical characteristics, PSA recurrence, molecular subtype defined by ERG status and 3p, 5q, 6q and PTEN deletion. RESULTS: BCAR1 staining was barely detectable in normal prostate glands but seen in 77.6% of 9472 interpretable cancers, including strong expression in 38.5%, moderate in 23.2% and weak in 15.9% of cases. BCAR1 up regulation was associated with positive ERG status (p < 0.0001), high Gleason score (p < 0.0001), advanced pathological tumor stage (p = 0.0082), lower preoperative PSA level (p < 0.0001), increased cell proliferation (p < 0.0001), early PSA recurrence (p = 0.0008), and predicted prognosis independently from clinico-pathological parameters available at the time of the initial biopsy. However, subset analyses revealed that the prognostic impact of BCAR1 expression was limited to ERG-negative cancer. That BCAR1 up regulation was linked to almost all analyzed deletions (p < 0.0001 each for PTEN, 5q, 6q deletion) may suggest a functional link to genomic instability. CONCLUSION: The results of our study identify BCAR1 as a prognostic biomarker with potential clinical value for risk stratification of ERG-negative prostate cancer.

Immunohistochemically detected IDH1R132H mutation is rare and mostly heterogeneous in prostate cancer.

BACKGROUND: IDH1 mutations are oncogenic through induction of DNA damage and genome instability. They are of therapeutic interest because they confer increased sensitivity to radiation and cytotoxic therapy and hold potential for vaccination therapy. METHODS: In this study, we analyzed more than 17,000 primary prostate cancer tissues with a mutation-specific antibody for the IDH1R132H mutation. RESULTS: IDH1 mutation-specific staining was found in 42 of 15,531 (0.3%) interpretable cancers. IDH1 mutation was associated with higher preoperative PSA and Gleason grade (p < 0.05, each) but was unrelated to PSA recurrence. A comparison with other molecular tumor features available from earlier studies revealed that TMPRSS2-ERG fusion as well as deletion of PTEN, 5q21, 6q15, and 3p13 was less frequent in IDH1-mutated than in non-mutated cancer. Increased lethality of genetically instable, "aberration-rich" cancer cells in the presence of IDH1 mutations could possibly explain this observation. Heterogeneity analysis revealed a homogeneous mutation in only 1 of 16 IDH1-mutated cancers. This high degree of heterogeneity may profoundly limit therapeutic targeting of IDH1 mutations in prostate cancer. CONCLUSIONS: The data show that 0.3% of prostate cancers have an IDH1R132H mutation and that these are mostly heterogeneous. Once specific anti-IDH1 therapy becomes reality, only a very small group of prostate cancer patients may benefit from such a treatment.

FOXA1 expression is a strong independent predictor of early PSA recurrence in ERG negative prostate cancers treated by radical prostatectomy.

FOXA1 (Fork-head box protein A1, HNF-3a) is a transcription factor involved in androgen signaling with relevance for lineage-specific gene expression of the prostate. The expression was analyzed by immunohistochemistry on a tissue microarray containing 11152 prostate cancer specimens. Results were compared with tumor phenotype, biochemical recurrence, androgen receptor expression, ETS-related gene (ERG) status and other recurrent genomic alterations. FOXA1 expression was detectable in 97.6% of 8227 interpretable cancers and considered strong in 28.5%, moderate in 46.2% and weak in 22.9% of cases. High FOXA1 expression was associated with TMPRSS2:ERG rearrangement and ERG expression (P < 0.0001). High FOXA1 expression was linked to high Gleason grade, advanced pathological tumor (pT) stage and early PSA recurrence in ERG negative cancers (P < 0.0001), while these associations were either weak or absent in ERG positive cancers. In ERG negative cancers, the prognostic role of FOXA1 expression was independent of Gleason grade, pathological tumor stage, lymph node stage, surgical margin status and preoperative PSA. Independent prognostic value became even more evident if the analysis was limited to preoperatively available features such as biopsy Gleason grade, preoperative PSA, cT stage and FOXA1 expression (P < 0.0001). Within ERG negative cancers, FOXA1 expression was also strongly associated with PTEN and 5q21 deletions (P < 0.0001). High expression of FOXA1 is an independent prognostic parameter in ERG negative prostate cancer. Thus, FOXA1 measurement might provide clinically useful information in prostate cancer.

Up-regulation of mismatch repair genes MSH6, PMS2 and MLH1 parallels development of genetic instability and is linked to tumor aggressiveness and early PSA recurrence in prostate cancer.

DNA mismatch repair (MMR) is integral to the maintenance of genetic stability. We aimed to evaluate the clinical impact of MMR gene expression in prostate cancer. The MMR genes MSH6, MLH1 and PMS2 were analyzed by immunohistochemistry on a tissue microarray containing 11152 prostate cancer specimens. Results were compared with ETS-related gene status and deletions of PTEN, 3p13, 5q21 and 6q15. MSH6, MLH1 and PMS2 expression was detectable in 89.5%, 85.4% and 85.0% of cancers and was particularly strong in cancers with advanced pathological tumor stage (P < 0.0001 each), high Gleason grade (P < 0.0001 each), nodal metastasis (P ≤ 0.0083) and early biochemical recurrence (P < 0.0001). High levels of MMR gene expression paralleled features of genetic instability, such as the number of genomic deletions per cancer; strong expression of all three MMR genes was found in 24%, 29%, 30%, 33% and 42% of cancers with no, one, two, three or four to five deletions (P < 0.0001). The prognostic value of the analyzed MMR genes was largely driven by the subset of cancers lacking ERG fusion (P < 0.0001), while the prognostic impact of MMR gene overexpression was only marginal in ERG-positive cancers. Multivariate analyses suggested an independent prognostic relevance of MMR genes in ERG-negative prostate cancers when compared with prognostic parameters available at the time of initial biopsy. In conclusion, MMR overexpression is common in prostate cancer and is linked to poor outcome as well as features indicating genetic instability. ERG fusion should be analyzed along with MMR gene expression in potential clinical tests.

High concordance of findings obtained from transgluteal magnetic resonance imaging - and transrectal ultrasonography-guided biopsy as compared with prostatectomy specimens.

OBJECTIVES: To determine the utility of our transgluteal magnetic resonance imaging (MRI)-guided prostate biopsy approach. PATIENTS AND METHODS: A total of 960 biopsy series, taken within the period of 1 year, were evaluated, including 301 MRI-guided and 659 transrectal ultrasonography (TRUS)-guided biopsies. RESULTS: The positivity rate and proportion of high grade cancers were significantly higher in MRI-guided than in TRUS-guided biopsies. Of 301 MRI-guided biopsies, 65.4% contained cancer while 57.2% of 659 TRUS biopsies contained cancer (P = 0.016). Gleason grade 3 + 3 = 6 disease was observed in 16.8% of 197 MRI-guided and in 36.1% of 377 TRUS-guided biopsies (P < 0.001). There was also a markedly higher quantity of cancer tissue in MRI-guided biopsies. In all cancers, the mean cancer surface area was 64.8 ± 51.6 mm2 in MRI-guided biopsies as compared with 23.0 ± 31.4 mm2 in non-MRI-guided biopsies (P < 0.001). With respect to the tissue quantity, superiority of MRI-guided biopsy was highest in Gleason grade 3 + 3 = 6 cancers (20.9 ± 27.9 vs 5.1 ± 10.2 mm2 ; P < 0.001) and in Gleason grade 3 + 4 = 7 cancers (59.7 ± 38.0 vs 17.7 ± 18.4 mm2 ; P < 0.001). Comparison of biopsy Gleason grades with findings in prostatectomy specimens was possible in 80 patients with MRI-guided and in 170 patients with non-MRI-guided biopsies. This comparison showed a very high but almost identical concordance of TRUS- and MRI-guided biopsies with the prostatectomy specimen findings. With both approaches, undetected high-risk cancers were present in ~10% of patients with low-risk biopsy results. A significant difference was observed, however, in the proportion of patients who had clinically insignificant cancers and who underwent surgery. The proportion of patients with Gleason grade 3 + 3 = 6 carcinoma in their prostatectomy specimen was 11.2% in the post-TRUS biopsy cohort, but only 2.5% in the post-MRI biopsy cohort (P = 0.021). CONCLUSION: MRI-guided transgluteal prostate biopsy has a high detection rate for high-risk carcinomas, while the risk of detecting clinically insignificant carcinomas appears to be reduced. This may by itself lead to a reduction of unnecessary prostatectomies. Overtreatment may be further avoided by better applicability of molecular testing to MRI-guided biopsies because of the excessive amount of tissue available for analysis, especially in patients with potential low-risk carcinomas.

High-Level γ-Glutamyl-Hydrolase (GGH) Expression is Linked to Poor Prognosis in ERG Negative Prostate Cancer.

γ-glutamyl-hydrolase (GGH) is a ubiquitously-expressed enzyme that regulates intracellular folate metabolism for cell proliferation, DNA synthesis, and repair. Employing GGH immunohistochemistry on a tissue microarray with 12,427 prostate cancers, we found that GGH expression was negative to low in normal prostate epithelium, whereas 88.3% of our 10,562 interpretable cancers showed GGH expression. GGH staining was considered as low intensity in 49.6% and as high intensity in 38.6% of cancers. High GGH expression was linked to the TMPRSS2:ERG-fusion positive subset of cancers (p < 0.0001), advanced pathological tumor stage, and high Gleason grade (p < 0.0001 each). Further analysis revealed that these associations were merely driven by the subset of ERG-negative cancers, High GGH expression was weakly linked to early biochemical recurrence in ERG negative cancers (p < 0.0001) and independent from established histo-pathological parameters. Moreover, GGH expression was linked to features of genetic instability, including presence of recurrent deletions at 3p, 5q, 6q, and 10q (PTEN, p ≤ 0.01 each), as well as to accelerated cell proliferation as measured by Ki67 immunohistochemistry (p < 0.0001). In conclusion, the results of our study identify GGH as an ERG subtype specific molecular marker with modest prognostic relevance, which may have clinical relevance if analyzed in combination with other molecular markers.

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.

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

BACKGROUND: ELAVL1 is an RNA binding protein involved in translation control, which might have a regulatory role in prostate cancer progress. METHODS: 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. RESULTS: 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. CONCLUSION: Our study identifies cytoplasmic accumulation of ELAVL1 as a predictor of adverse clinical behavior of prostate cancer independent of established clinico-pathological parameters.

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.

Heterogeneity of ERG expression in prostate cancer: a large section mapping study of entire prostatectomy specimens from 125 patients.

BACKGROUND: TMPRSS2:ERG fusions are frequent in prostate cancer, and occur predominantly in young patients. Several studies had proposed intratumoral heterogeneity of these fusions. This study was designed to determine frequency and extent of ERG fusion heterogeneity in early-onset prostate cancer (EO-PCA, <50 years) and in elderly patients. METHODS: The prostates from 63 EO-PCA and 62 elderly prostate cancer patients were thoroughly reviewed for presence of cancer foci. All 1592 tumor-containing sections were analyzed by immunohistochemistry for ERG expression. RESULTS: The prostates included in this study contained one tumor focus in 44, two tumor foci in 21, three tumor foci in 32, four tumor foci in 15, and five or more tumor foci in 13 patients. Among 59 cancer foci with ≤3 mm, 19 (32.2 %) were homogeneously ERG positive, 39 66.1 %) were homogeneously ERG negative, and one case (1.7 %) showed a heterogeneous ERG status. The fraction of homogeneously ERG positive cancer foci remained largely constant (14-37 %) with increasing tumor focus diameter but the fraction of heterogeneous ERG findings continuously increased with tumor size and reached 39 % in cancer foci larger than 22 mm. On a patient level, ERG expression was markedly more frequent in EO-PCA than in elderly patients: 13 % of EO-PCA were homogeneously and 62 % were heterogeneously ERG positive. In elderly patients, 3 % of cancers were homogeneously and 57 % were heterogeneously ERG positive (p = 0.0721). CONCLUSION: These data show that about 20-30 % of prostate cancer foci have early ERG fusions. ERG fusions further occur in about 50 % of initially ERG negative cancer foci during cancer progression. The vast majority of cancers are heterogeneous for TMPRSS2:ERG fusions on a patient level, challenging the concept of classifying prostate cancer patients into "fusion type" and "non-fusion type" prostate cancer.