Prostate cancer--uncertainty and a way forward

IMP3 accelerates the progression of prostate cancer through inhibiting PTEN expression in a SMURF1-dependent way

BACKGROUND

Insulin-like growth factor 2 (IGF2) messenger RNA binding protein 3 (IMP3) has been testified to be overexpressed in prostate cancer and strongly related to patients' poor prognosis. However, the functions of IMP3 and the underlying mechanisms in prostate cancer still remain unknown. Therefore, the current study was carried out to reveal the role and molecular mechanism of IMP3 in prostate cancer progression.

METHODS

The expression levels of IMP3 in prostate cancer tissues and cells were detected by immunohistochemistry (IHC), western blotting and RT-PCR. CCK-8, clone formation, flow cytometry and in vivo tumor formation assays were used to determine cell growth, clone formation apoptosis and tumorigenesis, respectively. The effect of IMP3 on the expression levels of the key proteins in PI3K/AKT/mTOR signaling pathway, including PIP2, PIP3, p-AKT, AKT, p-mTOR, mTOR, PTEN and BAD activation of was determined by western blotting. IP (Immunoprecipitation) assay was used to evaluate the effects of IMP3 and SMURF1 (SMAD specific E3 ubiquitin protein ligase 1) on the ubiquitination of PTEN protein.

RESULTS

IMP3 expression level was significantly increased in prostate cancer tissues and cell lines (LNCap, PC3 and DU145) as compared with the paracancerous normal tissues and cells (RWPE-1), respectively. High expression of IMP3 apparently promoted cell viability, tumorigenesis and inhibited cell apoptosis in prostate cancer LNCap, DU145 and PC3 cell lines. In mechanism, IMP3 upregulation significantly increased the phosphorylation levels of AKT and mTOR, and elevated PIP3 expression level, while induced significant reductions in the expression levels of BAD, PTEN and PIP2. And, IMP3 overexpression increased SMURF1 expression, which facilitated PTEN ubiquitination. In addition, SMURF1 overexpression enhanced prostate cancer cell viability and inhibited cell apoptosis. Silence of SMURF1 rescued the enhancements in cell proliferation and tumorigenesis and the inhibition in cell apoptosis rates induced by IMP3 in prostate cancer DU145 and LNCap cells.

CONCLUSION

This study reveals that IMP3 is overdressed in prostate cancer, which accelerates the progression of prostate cancer through activating PI3K/AKT/mTOR signaling pathway via increasing SMURF1-mediated PTEN ubiquitination.

High RSF1 protein expression is an independent prognostic feature in prostate cancer

Background: Remodelling and spacing factor 1 (RSF1) is involved in the regulation of chromatin remodelling and represents a potential therapeutic target. High RSF1 expression has been linked to adverse tumour features in many cancer types, but its role in prostate cancer is uncertain.Methods: In this study, RSF1 expression was analysed by immunohistochemistry on a tissue microarray with 17,747 prostate cancers.Results: Nuclear RSF1 staining of 16,456 interpetable cancers was considered strong, moderate, weak and negative in 25.2%, 48.7%, 5.3% and 20.8% of cancers respectively. Positive RSF1 expression was associated with advanced tumour stage, high Gleason grade, lymph node metastasis (p < .0001 each), early biochemical recurrence (p < .0003) and more frequent in the ERG positive than in the ERG negative subset (88% versus 71%; p < .0001). Subset analysis revealed, that associations between RSF1 expression and unfavourable tumour phenotype and PSA recurrence were present in both subgroups but stronger in the ERG negative than in the ERG positive subset. The univariate Cox proportional hazard ratio for PSA recurrence-free survival for strong versus negative RSF1 expression was a weak 1.60 compared with 5.91 for the biopsy Gleason grade ≥4 + 4 versus ≤3 + 3. The positive association of RSF1 protein detection with deletion of 3p13, 10q23 (PTEN), 12p13, 16q23, and 17p13 (p < .0001 each) suggest a role of high RSF1 expression in the development of genomic instability.Conclusion: In summary, the results of our study identify RSF1 as an independent prognostic marker in prostate cancer with a particularly strong role in ERG negative cases.

Loss of cytoplasmic survivin expression is an independent predictor of poor prognosis in radically operated prostate cancer patients

Survivin is an inhibitor of apoptosis. Aberrant survivin expression occurs in malignant tumors and has often been linked to unfavorable patient outcome. Here we analyzed 12 432 prostate cancers by immunohistochemistry. Survivin immunostaining was regularly expressed at high levels in normal prostate epithelium but expression was often reduced in prostate cancers. Among 9492 evaluable prostate cancers, 9% expressed survivin strongly, 19% moderately, 28% weakly, and 44% lacked it. Loss of cytoplasmic survivin was seen in advanced tumor stage, higher Gleason score, preoperative PSA levels, and Ki‐67 labeling index, and associated with earlier PSA recurrence (P < .0001). Survivin loss was significantly more common in cancers carrying TMPRSS2:ERG fusions (61% survivin negative) than in ERG wild‐type cancers (32% survivin negative; P < .0001). Multivariate analysis revealed that reduced cytoplasmic survivin expression predicted poor prognosis independent from Gleason score, pT, pN, and serum PSA level. This was valid for ERG‐positive and ERG‐negative cancers. Survivin expression loss even retained its prognostic impact in 1020 PTEN deleted cancers, a group that is already characterized by dismal patient prognosis. In conclusion, reduced survivin expression is associated with more aggressive tumors and inferior prognosis in prostate cancer.

Expression of CCCTC-binding factor (CTCF) is linked to poor prognosis in prostate cancer

The chromatin-organizing factor CCCTC-binding factor (CTCF) is involved in transcriptional regulation, DNA-loop formation, and telomere maintenance. To evaluate the clinical impact of CTCF in prostate cancer, we analyzed CTCF expression by immunohistochemistry on a tissue microarray containing 17 747 prostate cancers. Normal prostate tissue showed negative to low CTCF expression, while in prostate cancers, CTCF expression was seen in 7726 of our 12 555 (61.5%) tumors and was considered low in 44.6% and high in 17% of cancers. Particularly, high CTCF expression was significantly associated with the presence of the transmembrane protease, serine 2:ETS-related gene fusion: Only 10% of ERG-negative cancers, but 30% of ERG-positive cancers had high-level CTCF expression (P < 0.0001). CTCF expression was significantly associated with advanced pathological tumor stage, high Gleason grade (P < 0.0001 each), nodal metastasis (P = 0.0122), and early biochemical recurrence (P < 0.0001). Multivariable modeling revealed that the prognostic impact of CTCF was independent from established presurgical parameters such as clinical stage and Gleason grade of the biopsy. Comparison with key molecular alterations showed strong associations with the expression of the Ki-67 proliferation marker and presence of phosphatase and tensin homolog deletions (P < 0.0001 each). The results of our study identify CTCF expression as a candidate biomarker for prognosis assessment in prostate cancer.

Upregulation of SPDEF is associated with poor prognosis in prostate cancer

SAM pointed domain-containing Ets transcription factor (SPDEF), a member of the ETS transcription factor family, has been associated with prostate cancer development; however, its role in tumour development and progression is controversial. In the present study, SPDEF expression was analysed on a tissue microarray with >12,000 prostate cancer samples. SPDEF expression levels were higher in most prostate cancer samples than in normal prostate epithelium, suggesting SPDEF was upregulated in cancer. Nuclear SPDEF expression was identified in 80% of prostate cancer samples, and considered weak in 26.4%, moderate in 40.1% and strong in 13.5% of cases. SPDEF positivity was significantly associated with tumour stage, Gleason grade, lymph node metastasis and PSA recurrence (all P<0.0001). SPDEF overexpression was more common in ERG positive (94%) than in ERG negative cancer (69%; P<0.0001). Elevated SPDEF expression predicted poor prognosis independent from established prognostic parameters, including Gleason grade, pT, pN, serum PSA level and nodal status (P<0.01). In summary, SPDEF overexpression was associated with aggressive behaviour, particularly in ERG negative prostate cancer, and may have potential for clinical application.

Down-Regulation of S100A8 is an Independent Predictor of PSA Recurrence in Prostate Cancer Treated by Radical Prostatectomy

Dysregulation of S100A8 is described in many different human tumor types, but its role in prostate cancer is unknown. To evaluate the clinical relevance of S100A8 expression in prostate cancer, a tissue microarray containing 13,665 tumors was analyzed by immunohistochemistry. Cytoplasmic S100A8 staining was compared to prostate cancer phenotype, patient prognosis and molecular features including TMPRSS2:ERG fusion status and deletions of PTEN, 3p, 5q and 6q. S100A8 immunostaining was typically seen in normal prostate tissue but lost in 60% of 9786 interpretable prostate cancers. In the remaining tumors, S100A8 was considered weak in 17.9%, moderate in 17.8% and strong in 5.4% of cases. Loss of S100A8 expression was linked to advanced tumor stage, high Gleason grade, positive nodal status, positive surgical margin and high preoperative PSA (P < .0001 each). In addition, loss of S100A8 expression was associated with TMPRSS2:ERG fusions (P < .0001), deletions of PTEN, 3p, and 6q (P < .005), and a high number of genomic deletions per tumor (P = .0009). Absence of S100A8 immunostaining was also linked to an elevated risk for early PSA recurrence (P < .0001). In a multivariate analysis limited to features that are preoperatively available, the prognostic impact of S100A8 expression (P < .0001) was independent of clinical stage, Gleason grade, and serum PSA level (P < .0001). Taken together, the results of our study demonstrate that complete loss of S100A8 expression is linked to adverse tumor features and predicts early biochemical recurrence in prostate cancer. S100A8 measurement, either alone or in combination might be of clinical utility in 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.

Aberrant expression of the microtubule-associated protein tau is an independent prognostic feature in prostate cancer

Background

Microtubule-associated protein Tau (MAPT) overexpression has been linked to poor prognosis and decreased response to taxane-based therapies in several cancer types, but its relevance in prostate cancer is unknown.

Methods

In this study, MAPT expression was analyzed by immunohistochemistry on a tissue microarray containing 17,747 prostate cancers.

Results

MAPT was absent in normal prostate epithelial cells but detectable in 1004 (8.2%) of 12,313 interpretable cancers. Its expression was associated with advanced tumor stage, high Gleason grade, positive lymph nodes, and early biochemical recurrence (p < 0.0001 each). For example, MAPT was found in 3.6% of 2072 Gleason ≤3 + 3 cancers but in 14.4% of 704 Gleason ≥4 + 4 cancers. High-level MAPT staining was also linked to TMPRSS2:ERG fusions (p < 0.0001). MAPT staining was seen in 15.2 and 16% of cancers with TMPRSS2:ERG fusion detected by immunohistochemistry and fluorescence in-situ hybridization, but in only 3.5 and 3.9% of cancers without ERG staining or ERG rearrangements. Moreover, an association was found between MAPT expression and PTEN deletions, with 19% MAPT positivity in 948 PTEN deleted cancers but only 7% MAPT positivity in 3895 tumors with normal PTEN copy numbers (p < 0.0001). Multivariate analysis revealed that the prognostic value of MAPT was independent from established parameters. Conventional large section analyses showed intratumoral MAPT heterogeneity in all three analyzed cancers.

Conclusions

The results of our study identify MAPT, as a moderate prognostic marker in prostate cancer, whose clinical impact, however, may be limited due to the rarity and heterogeneity of its expression.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5390-1) contains supplementary material, which is available to authorized users.

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.

Upregulation of centromere protein F is linked to aggressive prostate cancers

Background

Centromere protein F (CENPF) is a key component of the kinetochore complex and plays a crucial role in chromosome segregation and cell cycle progression. Recent work suggests that CENPF upregulation is linked to aggressive tumor features in a variety of malignancies including prostate cancer.

Materials and methods

Using a highly annotated tissue microarray, we analyzed CENPF protein expression from a cohort of 8,298 prostatectomized patients by immunohistochemistry to study its effect on prostate-specific antigen recurrence-free survival.

Results

CENPF overexpression was found in 53% of cancers, and was linked to higher Gleason grade, advanced pathological tumor stage, accelerated cell proliferation, and lymph node metastasis (p<0.0001, each). A comparison with other key molecular features accessible through the microarray revealed strong associations between CENPF overexpression and presence of erythroblast transformation-specific (ETS)-related gene (ERG) fusion as well as phosphatase and tensin homolog deletion (p<0.0001, each). CENPF overexpression was linked to early biochemical recurrence. A subset analysis revealed that this was driven by the ERG-negative subset (p<0.0001). This was independent of established preoperative and postoperative prognostic parameters in multivariate analyses.

Conclusion

The results of our study identify CENPF overexpression as an important mechanism and a potential biomarker for prostate cancer aggressiveness.

Up regulation of the steroid hormone synthesis regulator HSD3B2 is linked to early PSA recurrence in prostate cancer

HSD3B2 plays a crucial role in steroid hormone biosynthesis and is thus of particular interest in hormone dependent tumors such as prostate cancer. To clarify the clinical relevance of HSD3B2 expression in prostate cancer, we analyzed HSD3B2 protein expression by immunohistochemistry on our preexisting tissue microarray with 12.247 annotated cancers. Compared with normal tissue cytoplasmic HSD3B2 staining was stronger in prostate cancers. In 9371 interpretable cancers, HSD3B2 expression was found in 95.5% of cancers and was considered weak in 29.9%, moderate in 40.7% and strong in 24.9%. HSD3B2 up regulation was linked to advanced pathological tumor stage (pT), high Gleason grade, elevated preoperative PSA levels (p < 0.0001 each), lymph node metastasis (p = 0.0019), accelerated cell proliferation (p < 0.0001), androgen receptor (AR) expression (p < 0.0001), and early biochemical recurrence (p < 0.0001). HSD3B2 up regulation was only marginally more frequent in ERG positive (98%) than in ERG negative cancers (94%; p < 0.0001) and was strongly linked to deletions of 5q and 6q (p < 0.0001 each). Multivariate analyses showed that the prognostic impact of HSD3B2 expression was independent of established preoperative, but not of postoperative prognostic parameters. In summary, the results of our study demonstrate that HSD3B2 is strongly up regulated in a fraction of prostate cancers that are characterized by increased AR signaling, adverse tumor phenotype and early biochemical recurrence.

Incorporating the Patient into Urologic Cancer Research

Patient engagement in research has been increasingly prioritized by funders and adopted by health researchers. In this Seminars issue, we explore several different mechanisms of engagement in the reciprocal relationship between patients and researchers. This includes the generation of understandable patient health information, how patients engage in treatment decision-making for urologic cancers, patient involvement in the development of research ideas and research design, and patient engagement in their personalized survivorship care.

Family with sequence similarity 13C (FAM13C) overexpression is an independent prognostic marker in prostate cancer

FAM13C, a gene with unknown function is included in several mRNA signatures for prostate cancer aggressiveness. To understand the impact of FAM13C on prognosis and its relationship to molecularly defined subsets, we analyzed FAM13C expression by immunohistochemistry on a tissue microarray containing 12,400 prostate cancer specimens. Results were compared to phenotype, ERG status, genomic deletions of 3p, 5q, 6q and PTEN, and biochemical recurrence. FAM13C was detectable in cell nuclei of cancerous and non-neoplastic prostate cells. 67.5% of 9,633 interpretable cancers showed FAM13C expression: strong in 28.3%, moderate in 24.6% and weak in 14.6%. Strong FAM13C expression was linked to advanced pT stage, high Gleason grade, positive lymph node status, and early biochemical recurrence (p < 0.0001 each). FAM13C expression was associated with TMPRSS2:ERG fusions. It was present in 85% of ERG positive but in only 54% of ERG negative cancers (p < 0.0001), and in 91.1% of PTEN deleted but in only 69.2% of PTEN non-deleted cancers (p < 0.0001). The prognostic role of FAM13C expression was independent of classical and quantitative Gleason grade, pT stage, pN stage, surgical margin status and preoperative PSA. In conclusion, the results of our study demonstrate that expression of FAM13C is an independent prognostic marker in prostate cancer. Finding FAM13C also in non-neoplastic prostate tissues highlights the importance of properly selecting cancer-rich areas for RNA-based FAM13C expression analysis.

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.

Overexpression of spindle and kinetochore-associated protein 1 contributes to the progression of prostate cancer

Spindle and kinetochore-associated protein 1 is a microtubule-binding subcomplex of the outer kinetochore that is essential for proper chromosome segregation. Recently, spindle and kinetochore-associated protein 1 has been highlighted as a biomarker in various cancers; however, the precise role of spindle and kinetochore-associated protein 1 in prostate cancer remains unknown. This study aims to evaluate whether spindle and kinetochore-associated protein 1 affects the biological behaviors of prostate cancer. We investigated the expression of spindle and kinetochore-associated protein 1 in a series of prostate cancer tissues as well as in a panel of prostate cancer cell lines. Cell proliferation, migration, and invasion were evaluated in spindle and kinetochore-associated protein 1 knockdown prostate cancer cell lines by MTT and Transwell assays. Our results showed that the expression of spindle and kinetochore-associated protein 1 was remarkably upregulated in prostate cancer at both messenger RNA and protein levels compared with non-cancerous tissue. Knockdown of spindle and kinetochore-associated protein 1 repressed the ability of cell proliferation, migration, and invasion of prostate cancer cells. Moreover, inhibition of spindle and kinetochore-associated protein 1 could inhibit the activity of AKT and ERK pathway. In conclusion, our findings suggest that spindle and kinetochore-associated protein 1 could serve as a potential therapeutic target in prostate cancer patients.

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.

Overexpression of the A Disintegrin and Metalloproteinase ADAM15 is linked to a Small but Highly Aggressive Subset of Prostate Cancers

The A Disintegrin and Metalloproteinase (ADAM) family of endopeptidases plays a role in many solid cancers and includes promising targets for anticancer therapies. Deregulation of ADAM15 has been linked to tumor aggressiveness and cell line studies suggest that ADAM15 overexpression may also be implicated in prostate cancer. To evaluate the impact of ADAM15 expression and its relationship with key genomic alterations, a tissue microarray containing 12,427 prostate cancers was analyzed by immunohistochemistry. ADAM15 expression was compared to phenotype, prognosis and molecular features including TMPRSS2:ERG fusion and frequent deletions involving PTEN, 3p, 5q and 6q. Normal prostate epithelium did not show ADAM15 staining. In prostate cancers, negative, weak, moderate, and strong ADAM15 staining was found in 87.7%, 3.7%, 5.6%, and 3.0% of 9826 interpretable tumors. Strong ADAM15 staining was linked to high Gleason grade, advanced pathological tumor stage, positive nodal stage and resection margin. ADAM15 overexpression was also associated with TMPRSS2:ERG fusions and PTEN deletions (P<.0001) but unrelated to deletions of 3p, 5q and 6q. In univariate analysis, high ADAM15 expression was strongly linked to PSA recurrence (P<.0001). However, in multivariate analyses this association was only maintained if the analysis was limited to preoperatively available parameters in ERG-negative cancers. The results of our study demonstrate that ADAM15 is strongly up regulated in a small but highly aggressive fraction of prostate cancers. In these tumors, ADAM15 may represent a suitable drug target. In a preoperative scenario, ADAM15 expression measurement may assist prognosis assessment, either alone or in combination with other markers.

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.

[Early detection or screening in the prevention of prostate cancer?]

Prostate cancer (PC) is the most common malignancy in men in the developed world and the second leading cause of cancer death in men in the USA, behind lung cancer. In Europe, it is the third leading cause of cancer death in men (after lung and colorectal cancers). The role of PC screening is currently being questioned. The following article summarises the most relevant epidemiological aspects of PC, as well as major clinical trials of PC screening, and recommendations of the various medical scientific associations on whether or not to screen for PC.

Identifying risk in the use of tumor markers to improve patient safety

Background:

Tumor markers (TM) are a routine test that are not always used well, and can lead to unnecessary additional tests, which are not without risks for the patients. So, to implement appropriate strategies to improve the adequate use of TM and, therefore, improve patient safety, is required to analyze the use of TM, identifying risks and establishing if there are differences in their use as a function of their utility.

Methods:

The study was a descriptive, longitudinal, retrospective and systematic study in the area covered by the University Hospital of Padua. In the follow-up 2-year study, 23,059 analytical requests of TM, corresponding to 14,728 patients, were analyzed. For the level of statistical significance it applies an approximation of the normal law (Z statistic) and χ

Results:

Only 9196 requests (39.88%) out of a total of 23,059 on 5080 patients with neoplastic diseases have been classified as adecuate according to current guidelines. The number of requests per patient was variable (1.57±1.35). In patients with neoplastic diseases this increased to 1.80±1.68. The mean of number of TM per request was 2.4±1.73. The analysis showed an association between the number of requests and the type of marker used.

Conclusions:

The use of TM is variable, mainly of the follow-up markers, when they are used as screening. This inappropriate use, minimizes their utility favoring erroneous interpretations and increases the risk of damage to the patient. So it is essential to implement safe practices in the use of TM.

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

PURPOSE

Sequestosome 1 (p62) is a multifunctional adapter protein accumulating in autophagy-defective cells.

EXPERIMENTAL DESIGN

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.

RESULTS

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.

CONCLUSIONS

Our study identifies cytoplasmic accumulation of p62 as a strong predictor of an adverse prognostic behavior of prostate cancer independently from established clinicopathologic findings.

VEGFR-1 overexpression identifies a small subgroup of aggressive prostate cancers in patients treated by prostatectomy

The VEGFR-1 is suggested to promote tumor progression. In the current study we analyzed prevalence and prognostic impact of the VEGFR-1 by immunohistochemistry on a tissue microarray containing more than 3000 prostate cancer specimens. Results were compared to tumor phenotype, ETS-related gene (ERG) status, and biochemical recurrence. Membranous VEGFR-1 expression was detectable in 32.6% of 2669 interpretable cancers and considered strong in 1.7%, moderate in 6.7% and weak in 24.2% of cases. Strong VEGFR-1 expression was associated with TMPRSS2:ERG fusion status as determined by fluorescence in situ hybridization (FISH) and immunohistochemistry (p < 0.0001 each). Elevated VEGFR-1 expression was linked to high Gleason grade and advanced pT stage in TMPRSS2:ERG negative cancers (p = 0.0008 and p = 0.001), while these associations were absent in TMPRSS2:ERG positive cancers. VEGFR-1 expression was also linked to phosphatase and tensin homolog (PTEN) deletions. A comparison with prostate specific antigen (PSA) recurrence revealed that the 1.7% of prostate cancers with the highest VEGFR-1 levels had a strikingly unfavorable prognosis. This could be seen in all cancers, in the subsets of TMPRSS2:ERG positive or negative, PTEN deleted or undeleted carcinomas (p < 0.0001 each). High level VEGFR-1 expression is infrequent in prostate cancer, but identifies a subgroup of aggressive cancers, which may be candidates for anti-VEGFR-1 targeted therapy.

ESTIMATING PERSON-CENTERED TREATMENT (PeT) EFFECTS USING INSTRUMENTAL VARIABLES: AN APPLICATION TO EVALUATING PROSTATE CANCER TREATMENTS

This paper builds on the methods of local instrumental variables developed by Heckman and Vytlacil (1999, 2001, 2005) to estimate person-centered treatment (PeT) effects that are conditioned on the person's observed characteristics and averaged over the potential conditional distribution of unobserved characteristics that lead them to their observed treatment choices. PeT effects are more individualized than conditional treatment effects from a randomized setting with the same observed characteristics. PeT effects can be easily aggregated to construct any of the mean treatment effect parameters and, more importantly, are well suited to comprehend individual-level treatment effect heterogeneity. The paper presents the theory behind PeT effects, and applies it to study the variation in individual-level comparative effects of prostate cancer treatments on overall survival and costs.

Turning off AKT: PHLPP as a drug target

Precise control of the balance between protein phosphorylation, catalyzed by protein kinases, and protein dephosphorylation, catalyzed by protein phosphatases, is essential for cellular homeostasis. Dysregulation of this balance leads to pathophysiological states, driving diseases such as cancer, heart disease, and diabetes. Aberrant phosphorylation of components of the pathways that control cell growth and cell survival are particularly prevalent in cancer. One of the most studied tumor suppressors in these pathways is the lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome ten), which dephosphorylates the lipid second messenger phosphatidylinositol 3,4,5-trisphosphate (PIP3), thus preventing activation of the oncogenic kinase AKT (v-akt murine thymoma viral oncogene homolog). In 2005, the discovery of a family of protein phosphatases whose members directly dephosphorylate and inactivate AKT introduced a new negative regulator of the phosphoinositide 3-kinase (PI3K) oncogenic pathway. Pleckstrin homology domain leucine-rich repeat protein phosphatase (PHLPP) isozymes comprise a novel tumor suppressor family whose two members, PHLPP1 and PHLPP2, are deleted as frequently as PTEN in cancers such as those of the prostate. PHLPP is thus a novel therapeutic target to suppress oncogenic pathways and is a potential candidate biomarker to stratify patients for the appropriate targeted therapeutics. This review discusses the role of PHLPP in terminating AKT signaling and how pharmacological intervention would impact this pathway.

Addressing overdiagnosis and overtreatment in cancer: a prescription for change

A vast range of disorders--from indolent to fast-growing lesions--are labelled as cancer. Therefore, we believe that several changes should be made to the approach to cancer screening and care, such as use of new terminology for indolent and precancerous disorders. We propose the term indolent lesion of epithelial origin, or IDLE, for those lesions (currently labelled as cancers) and their precursors that are unlikely to cause harm if they are left untreated. Furthermore, precursors of cancer or high-risk disorders should not have the term cancer in them. The rationale for this change in approach is that indolent lesions with low malignant potential are common, and screening brings indolent lesions and their precursors to clinical attention, which leads to overdiagnosis and, if unrecognised, possible overtreatment. To minimise that potential, new strategies should be adopted to better define and manage IDLEs. Screening guidelines should be revised to lower the chance of detection of minimal-risk IDLEs and inconsequential cancers with the same energy traditionally used to increase the sensitivity of screening tests. Changing the terminology for some of the lesions currently referred to as cancer will allow physicians to shift medicolegal notions and perceived risk to reflect the evolving understanding of biology, be more judicious about when a biopsy should be done, and organise studies and registries that offer observation or less invasive approaches for indolent disease. Emphasis on avoidance of harm while assuring benefit will improve screening and treatment of patients and will be equally effective in the prevention of death from cancer.

Can we deliver randomized trials of focal therapy in prostate cancer?

Tissue-preserving focal therapies, such as brachytherapy, cryotherapy, high-intensity focused ultrasound and photodynamic therapy, aim to target individual cancer lesions rather than the whole prostate. These treatments have emerged as potential interventions for localized prostate cancer to reduce treatment-related adverse-effects associated with whole-gland treatments, such as radical prostatectomy and radiotherapy. In this article, the Prostate Cancer RCT Consensus Group propose that a novel cohort-embedded randomized controlled trial (RCT) would provide a means to study men with clinically significant localized disease, which we defined on the basis of PSA level (≤ 15 ng/ml or ≤ 20 ng/ml), Gleason grade (Gleason pattern ≤ 4 + 4 or ≤ 4 + 3) and stage (≤ cT2cN0M0). This RCT should recruit men who stand to benefit from treatment, with the control arm being whole-gland surgery or radiotherapy. Composite outcomes measuring rates of local and systemic salvage therapies at 3-5 years might best constitute the basis of the primary outcome on which to change practice.

Does robotic prostatectomy meet its promise in the management of prostate cancer?

Following Walsh's advances in pelvic anatomy and surgical technique to minimize intraoperative peri-prostatic trauma more than 30 years ago, open retropubic radical prostatectomy (RRP) evolved to become the gold standard treatment of localized prostate cancer, with excellent long-term survival outcomes [1•]. However, RRP is performed with great heterogeneity, even among high volume surgeons, and subtle differences in surgical technique result in clinically significant differences in recovery of urinary and sexual function. Since the initial description of robotic-assisted radical prostatectomy (RARP) in 2000 [2], and U.S. Food and Drug Administration approval shortly thereafter, RARP has been rapidly adopted and has overtaken RRP as the most popular surgical approach in the management of prostate cancer in the United States [3]. However, the surgical management of prostate cancer remains controversial. This is confounded by the idolatry of new technologies and aggressive marketing versus conservatism in embracing tradition. Herein, we review the literature to compare RRP to RARP in terms of perioperative, oncologic, and quality-of-life outcomes as well as healthcare costs. This is a particularly relevant, given the absence of randomized trials and long-term (more than 10-year) follow-up for RARP biochemical recurrence-free survival.

Serum isoform [-2]proPSA derivatives significantly improve prediction of prostate cancer at initial biopsy in a total PSA range of 2-10 ng/ml: a multicentric European study

BACKGROUND

Strategies to reduce prostate-specific antigen (PSA)-driven prostate cancer (PCa) overdiagnosis and overtreatment seem to be necessary.

OBJECTIVE

To test the accuracy of serum isoform [-2]proPSA (p2PSA) and its derivatives, percentage of p2PSA to free PSA (fPSA; %p2PSA) and the Prostate Health Index (PHI)-called index tests-in discriminating between patients with and without PCa.

DESIGN, SETTING, AND PARTICIPANTS

This was an observational, prospective cohort study of patients from five European urologic centers with a total PSA (tPSA) range of 2-10 ng/ml who were subjected to initial prostate biopsy for suspected PCa.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point was to evaluate the specificity, sensitivity, and diagnostic accuracy of index tests in determining the presence of PCa at prostate biopsy in comparison to tPSA, fPSA, and percentage of fPSA to tPSA (%fPSA) (standard tests) and the number of prostate biopsies that could be spared using these tests. Multivariable logistic regression models were complemented by predictive accuracy analysis and decision curve analysis.

RESULTS AND LIMITATIONS

Of >646 patients, PCa was diagnosed in 264 (40.1%). Median tPSA (5.7 vs 5.8 ng/ml; p=0.942) and p2PSA (15.0 vs 14.7 pg/ml) did not differ between groups; conversely, median fPSA (0.7 vs 1 ng/ml; p<0.001), %fPSA (0.14 vs 0.17; p<0.001), %p2PSA (2.1 vs 1.6; p<0.001), and PHI (48.2 vs 38; p<0.001) did differ significantly between men with and without PCa. In multivariable logistic regression models, p2PSA, %p2PSA, and PHI significantly increased the accuracy of the base multivariable model by 6.4%, 5.6%, and 6.4%, respectively (all p<0.001). At a PHI cut-off of 27.6, a total of 100 (15.5%) biopsies could have been avoided. The main limitation is that cases were selected on the basis of their initial tPSA values.

CONCLUSIONS

In patients with a tPSA range of 2-10 ng/ml, %p2PSA and PHI are the strongest predictors of PCa at initial biopsy and are significantly more accurate than tPSA and %fPSA.

Integrating disparate snippets of information in an approach to PSA testing in Australia and New Zealand

• An invited response to 'Stricker PD, Frydenberg M, Kneebone A, Chopra S. Informed prostate cancer risk-adjusted testing: a new paradigm'.