Utility of tissue microarrays for profiling prognostic biomarkers in clinically localized prostate cancer: the expression of BCL-2, E-cadherin, Ki-67 and p53 as predictors of biochemical failure after radical prostatectomy with nested control for clinical and pathological risk factors.

A cure cannot be assured for all men with clinically localized prostate cancer undergoing radical treatment. Molecular markers would be invaluable if they could improve the prediction of occult metastatic disease. This study was carried out to investigate the expression of BCL-2, Ki-67, p53 and E-cadherin in radical prostatectomy specimens. We sought to assess their ability to predict early biochemical relapse in a specific therapeutic setting. Eighty-two patients comprising 41 case pairs were matched for pathological stage, Gleason grade and preoperative prostate-specific antigen (PSA) concentration. One patient in each pair had biochemical recurrence (defined as PSA >or= 0.2 ng mL(-1) within 2 years of surgery) and the other remained biochemically free of disease (defined as undetectable PSA at least 3 years after surgery). Immunohistochemical analysis was performed to assess marker expression on four replicate tissue microarrays constructed with benign and malignant tissue from each radical prostatectomy specimen. Ki-67, p53 and BCL-2, but not E-cadherin, were significantly upregulated in prostate adenocarcinoma compared with benign prostate tissue (P < 0.01). However, no significant differences in expression of any of the markers were observed when comparing patients who developed early biochemical relapse with patients who had no biochemical recurrence. This study showed that expression of p53, BCL-2 and Ki-67 was upregulated in clinically localized prostate cancer compared with benign prostate tissue, with no alteration in E-cadherin expression. Biomarker upregulation had no prognostic value for biochemical recurrence after radical prostatectomy, even after considering pathological stage, whole tumour Gleason grade and preoperative serum PSA level.

Allelic imbalance at 13q14.2 approximately q14.3 in localized prostate cancer is associated with early biochemical relapse.

Allelic imbalance (AI), particularly at chromosomes 8p, 10q, and 13q, is the most frequently observed genetic change in sporadic prostate cancer. AI at these sites may inactivate tumor suppressor genes that regulate normal cell growth. To establish the relationship between AI and progression, we analyzed loci on 8p, 10q, and 13q14 in archival prostate tumors matched for Gleason grade, pre-operative prostate-specific antigen levels, and pathologic stage, and they were paired on the basis of relapse status after 3 years. AI was identified in 66% of patients without relapse and in 73% with relapse. There was no statistically significant difference for AI at 8p21.3 and 10q23.2 between the two groups of patients, but significant differences between relapsers and nonrelapsers in the frequency of AI at D13S165 at 13q14.2 (P=0.006) and D13S273 at 13q14.3 (P=0.03). There was also a significantly higher incidence of AI at both loci in the relapsers compared to the nonrelapsers (P=0.03). In three relapsers, AI occurred at all three loci between 13q14.2 and 13q14.3, with no nonrelapsers demonstrating AI at all three loci. These findings show that AI at 13q14.2 approximately q14.3 is an important event in the progression of localized prostate cancer, and suggest a possible role for microRNAs.