Combined c-Myc and caveolin-1 expression in human prostate carcinoma predicts prostate carcinoma progression

BACKGROUND: Over-expression of the oncogene c-Myc has been implicated in the development and progression of human prostate carcinoma. However, previous assessments of c-Myc expression have not revealed its potential for predicting prostate carcinoma progression. Caveolin-1 is associated with prostate carcinoma progression and is a downstream target gene of c-Myc. The observation that caveolin-1 can suppress c-Myc-induced apoptosis suggested the potential for cooperation between c-Myc and caveolin-1 in malignant progression. In this study, the authors evaluated the prognostic potential of combined c-Myc and caveolin-1 expression in human prostate carcinoma progression. METHODS: Immunostaining with c-Myc and caveolin-1-specific antibodies was performed on paraffin sections from 104 radical prostatectomy specimens from men with lymph node negative prostate carcinoma. Combined c-Myc and caveolin-1 immunostaining scores were related with the clinical and pathologic features and the probability of prostate-specific antigen recurrence after surgery. RESULTS: The combination of c-Myc and caveolin-1 immunopositivity correlated positively with Gleason score (rho = 0.219; P = 0.0253) and positive surgical margin (rho = 0.333; P = 0.0006). The combination of positive c-Myc and caveolin-1 in patients with clinically confined prostate carcinoma was a significant prognostic marker for the time to disease progression after surgery in both univariate analysis (P = 0.0039; hazard ratio, 3.035) and multivariate analysis (P = 0.0114; hazard ratio, 2.916). CONCLUSIONS: The coexpression of c-Myc and caveolin-1 showed potential as a useful prognostic marker for human prostate carcinoma. The current results suggest interactions between c-Myc and caveolin-1 in the progression of human prostate carcinoma.     

Caveolin-1 expression is a predictor of recurrence-free survival in pT2N0 prostate carcinoma diagnosed in Japanese patients

BACKGROUND: The authors previously identified elevated caveolin-1 expression in human prostate carcinoma and determined that caveolin-1 levels as detected by immunohistochemistry of radical prostatectomy specimens offered novel prognostic information. A higher incidence of caveolin-1 expression also was reported in African-American men compared with white men in the U.S. To explore these ethnic/racial differences in caveolin-1 expression further, the authors evaluated caveolin-1 expression as a predictive marker in Japanese men with prostate carcinoma. METHODS: Immunohistochemical staining with a caveolin-1 specific antibody was performed on routinely processed paraffin sections from 152 consecutively collected radical prostatectomy specimens. The mean patient age was 64.3 years (range, 49-74 years; median, 64.5 years) and the mean follow-up period was 49.5 months (range, 1.3-103.3 months; median, 48.2 months). Caveolin-1 immunoreactivity was evaluated in association with patient's age; preoperative prostate specific antigen level; clinical stage; and pathologic features including Gleason score, extraprostatic extension, status of surgical margins, seminal vesicle involvement, lymph node involvement, and time to disease progression after surgery. RESULTS: Positive caveolin-1 immunostaining was detected in 46 of the 152 tumors (30.3%) and was found to be associated significantly with a positive surgical margin (P = 0.022). A higher incidence of caveolin-1 expression tended to be found in patients with poorly differentiated tumors (Gleason score > 7, 6-7, and < 6, 35.0% vs. 34.9% vs. 20.4%, respectively) or in patients with extraprostatic extension versus those without extraprostatic extension (35.4% vs. 24.7%) or patients with lymph node involvement compared with those without lymph node involvement (50% vs. 29.5%), although these differences did not reach statistical significance (P = 0.100, P = 0.150, and P = 0.178, respectively, by the Spearman correlation test). Kaplan-Meier analysis revealed that increased caveolin-1 expression was associated with an increased risk of disease progression at 5 years (P = 0.0122 by the log-rank test). In patients with organ-confined (pT2N0) disease, univariate Cox proportional hazards regression analysis revealed that positive caveolin-1 expression was the only significant predictor of disease recurrence after radical prostatectomy (P = 0.011; hazards ratio = 4.75; and 95% confidence interval, 1.43-15.76). CONCLUSIONS: The results of the current study confirm that positive caveolin-1 expression is associated with clinical markers of disease progression and is predictive of poor clinical outcome after surgery in Japanese patients with pT2N0 prostate carcinoma.     

Overexpression of caveolin-1 in esophageal squamous cell carcinoma correlates with lymph node metastasis and pathologic stage

BACKGROUND: Caveolin-1 plays a regulatory role in several signaling pathways. Recently caveolin-1 was identified as a metastasis-related gene in prostate carcinoma. However, the clinical impact of caveolin-1 expression in esophageal carcinoma remains unknown. METHODS: One hundred thirty surgical specimens of esophageal squamous cell carcinoma were immunohistochemically assessed for caveolin-1 expression by polyclonal antibody. Caveolin-1 immunoreactivity was correlated with patients' clinicopathologic parameters and outcome. RESULTS: Positive caveolin-1 immunostaining was detected in 58 patients (44.6%). Positive caveolin-1 immunostaining correlated positively with pathologic stage (P = 0.029), pN (P = 0.023), and pM (P = 0.018). The overall survival rate was worse in patients with caveolin-1-positive tumors than in patients with caveolin-1-negative tumors (P = 0.0215). Univariate analyses identified caveolin-1 positivity (P = 0.0238), pT (P = 0.0002), pN (P < 0.0001), pM (P = 0.0002), lymphatic invasion (P = 0.0021), and positive surgical margin (P < 0.0001) as negative prognostic predictors. Multivariate analyses indicated that pT (P = 0.0296), pN (P = 0.0003), and a positive surgical margin (P = 0.0452) were independent prognostic factors. CONCLUSIONS: Over-expression of caveolin-1 is associated with lymph node metastasis and a worse prognosis after surgery in esophageal squamous cell carcinoma.     

Reduced infiltration of class A scavenger receptor positive antigen-presenting cells is associated with prostate cancer progression

The class A macrophage scavenger receptor (SR-A) is expressed in antigen presenting cells and is involved in host immune responses. Germ-line mutation of this gene has been associated with increased risk of human prostate cancer. However, there is little known about its expression in normal or neoplastic human prostate tissues. Double immunofluorescent labeling with monoclonal antibodies to SR-A and specific macrophage and dendritic cell markers was used to identify cells expressing SR-A in human prostate tissues. SR-A immunohistochemical staining was performed on paraffin sections of normal prostate, prostatic intraepithelial neoplasia (PIN) lesions, and prostate cancers from radical prostatectomy specimens. SR-A was expressed in a subset of macrophages and dendritic cells that infiltrated prostatic tissues. The majority of SR-A-positive cells coexpressed CD68, and a relatively low percentage expressed S100 protein. The number of SR-A-positive cells was significantly increased in PIN as compared with normal prostatic tissue (P = 0.0176). In contrast, the number of SR-A-positive cells decreased with tumor progression. A lower SR-A-positive cell density was associated with higher clinical stage (rho = -0.26; P = 0.0234). Inverse associations were also found between SR-A density and positive lymph nodes (rho = -0.23; P = 0.0437), tumor size (rho = -0.31; P = 0.0100) and preoperative PSA levels (rho = -0.32; P = 0.0057). SR-A density is a significant predictor of disease-free survival after surgery univariately (P = 0.0003), as well as multivariately, adjusted for known clinical and pathological markers including preoperative prostate-specific antigen, clinical stage, Gleason score, surgical margin, extraprostatic extension, and seminal vesicle invasion, as well as lymph node metastasis (P = 0.0021). The preferential accumulation of SR-A-positive cells in PIN suggests a role for SR-A in the APC response to early malignancy. A reduction in the number of SR-A-positive cells demarcates tumor progression as indicated by clinical and pathological correlations. Our results additionally indicate that systematic measurement of SR-A density is a strong prognostic marker for clinical outcome after surgery.     

Elevated caveolin-1 levels in African-American versus white-American prostate cancer.

Clinical studies suggest that African-American (AA) prostate cancer patients manifest a more aggressive form of the disease compared with white prostate cancer patients. However, the biological underpinnings of this potential difference remain unresolved. To address this issue, we used specific quantitative immunostaining protocols to determine whether a panel of biomarkers related to apoptosis including caveolin-1, bcl-2, p53, and c-myc were differentially expressed in AA versus white prostate cancer patients with similar clinical and pathological characteristics. We further attempted to correlate biomarker positivity with proliferation-related markers including Ki-67 labeling index and apoptotic index. Interestingly, our results indicated that only the incidence of caveolin-1 staining was significantly different between these two ethnic/racial groups of prostate cancer patients. The incidence of caveolin-1 staining in white patients was 17% compared with 39% in AA patients (P = 0.0048; Fisher's exact test). In addition, the percentage of caveolin-1-positive prostate cancer cells was also higher in moderately differentiated (Gleason score 6) prostate cancer patients in AA versus whites. Because caveolin-1 has been shown previously to demonstrate antiapoptotic activities in prostate cancer cells, our results suggest that differences in caveolin-1 expression may in part underlie the apparent differences in the clinical virulence of this disease in AA versus white prostate cancer patients.     

Reduced infiltration of tumor-associated macrophages in human prostate cancer: association with cancer progression

Tumor-associated macrophages (TAMs) are highly active immune effector cells that may either positively or negatively regulate the growth of various malignant cells, depending on the biological context. However, the role of TAMs in human prostate cancer progression is unclear. TAMs were immunohistochemically labeled using a monoclonal (CD68) antibody in radical prostatectomy specimens derived from 81 prostate cancer patients. CD68-positive cells were counted with the aid of a microscope and expressed as macrophage index (MphiI), including TAMs/mm2 total tumor tissue (MphiItotal), TAMs/mm2 tumor stroma (MphiIstroma), and TAMs/mm2 cancer cell area (MphiIcancer). MphiIs were analyzed in association with patients' clinical and pathological stage, recurrence status, and histological grade of the cancer. There were significant inverse relationships between MphiItotal and MphiIstroma and clinical stage (P = 0.016 and P = 0.006, respectively). Reduced MphiItotal was also associated with the presence of positive lymph nodes (P = 0.010). Interestingly, although all of the MphiIs differed between Gleason score groups, only MphiIcancer was positively associated with Gleason score. Univariate analysis of MphiItotal and multivariate analysis of MphiItotal with specific pathological markers revealed that MphiItotal was an independent predictor for disease-free survival after surgery (Cox proportional hazard model, P = 0.044 and P = 0.007, respectively). For patients with high MphiItotal (> or = 185.8, the mean MphiItotal value), the disease-free probability 5 years after surgery was 0.75, which was significantly higher than for those with low MphiItotal (0.31, P = 0.0008). Additional immunohistochemical studies that evaluated cytotoxicity-related biomarkers in stroma-associated mononuclear cells suggested reduced functional activities in highly aggressive prostate cancer compared with less aggressive disease. Our results indicate that reduced MphiItotal is a novel prognostic marker for prostate cancer.     

Prognostic significance of epithelial/stromal caveolin‐1 expression in prostatic hyperplasia,high grade prostatic intraepithelial hyperplasia and prostatic carcinoma and its correlation with microvessel density

Caveolin-1 may play a role in cancer development and progression. The aim was to record the expression and localization of caveolin-1 in benign prostatic hyperplasia (BPH), high grade prostatic intraepithelial neoplasia (HGPIN) and prostatic carcinoma (PCa). Microvessel density was evaluated with CD34 immunostain. Correlations with known prognostic factors of PCa were recorded. Immunohistochemical expression of caveolin-1 and the MVD was evaluated in 65 cases; BPH (25), HGPIN (20) and PCa (20). Stromal caveolin-1expression was significantly higher in BPH than HGPIN and PCca. There was significant inverse relation between stromal caveolin-1 expression and extension to lymph node and seminal vesicle in carcinoma cases. Epithelial caveolin-1 was significantly higher in carcinomas than in BPH and HGPIN. Epithelial expression in carcinoma was significantly associated with preoperative PSA, Gleason score and lymph node extension. MVD was significantly higher in PCa than in BPH and HGPIN. There were significant relations between MVD and preoperative PSA, Gleason score, lymph node and seminal vesicle extension. Stromal caveolin-1 was associated with low MVD while epithelial caveolin-1 with high MVD. Conclusions: Caveolin-1 plays an important role in prostatic carcinogenesis and metastasis. Stromal expression of caveolin-1 in PCa is lowered in relation to BPH and HGPIN. In PCa; stromal caveolin-1 was associated with good prognostic parameters. Epithelial caveolin-1 is significantly increased in PCa than BPH and HGPIN. It is associated with clinically aggressive disease. Caveolin-1 may play a role in angiogenesis.     

Survival advantage from higher-dose radiation therapy for clinically localized prostate cancer treated on the Radiation Therapy Oncology Group trials.

PURPOSE: We evaluated the effect of external-beam radiation therapy on disease-specific survival (death from causes related to prostate cancer) and overall survival in men with clinically localized prostate cancer. METHODS: From 1975 to 1992, 1,465 men with clinically localized prostate cancer received radiation therapy on four Radiation Therapy Oncology Group phase III randomized trials and were pooled for this analysis. No one received androgen-deprivation therapy with his initial treatment. All original histology had central pathologic review for grading using the Gleason classification system. Total delivered radiation dose ranged from 60 to 78 Gy (median, 68.4 Gy). The median follow-up time was 8 years. RESULTS: A Cox regression model revealed that Gleason score was an independent predictor of disease-specific survival and overall survival. The 10-year disease-specific survival rates by Gleason score were as follows: score of 2 through 5, 85%; score of 6, 79%; score of 7, 62%; and score of 8 through 10, 43%. Stratifying outcome by this important prognostic factor revealed that higher radiation dose was a significant predictor for improved disease-specific survival and overall survival only for those patients whose cancers had Gleason scores of 8 through 10 (P <.05). After adjusting for clinical T stage, nodal status, and age, treating with a higher radiation dose was associated with a 29% lower relative risk of death from prostate cancer and 27% reduced mortality rate (P <.05). CONCLUSION: These data demonstrate that higher-dose radiation therapy can significantly reduce the risk of dying from prostate cancer in men with clinically localized disease. This survival benefit is restricted to men with poorly differentiated cancers.     

Impact of caveolin-1 expression on prognosis of pancreatic ductal adenocarcinoma

Caveolin-1 is a major component of caveolae and plays a regulatory role in several signalling pathways. Caveolin-1 was recently identified as a metastasis-related gene in prostate cancer. The clinical effects of caveolin-1 expression in pancreatic carcinoma, however, remain unknown. In this study, we have investigated the relationship between caveolin-1 expression and the clinicopathologic variables and clinical outcome in 79 patients with pancreatic adenocarcinoma undergoing surgical resection. Caveolin-1 expression was determined by immunohistochemistry, using a polyclonal anti-caveolin-1 antibody. Patients were divided into two groups based on the extent of caveolin-1 expression: a negative expression group (immunoreactivity in less than 50% of cells) and a positive expression group. Positive caveolin-1 immunostaining was detected in 32 cases (40.5% of total), while non-neoplastic ductal epithelium showed little or no staining. Positive caveolin-1 expression was correlated with tumour diameter (P=0.0079), histopathologic grade (P=0.0272) and poor prognosis (P=0.0008). Upon multivariate analysis with Cox's proportional hazards model, positive caveolin-1 expression was shown to be an independent negative predictor for survival (P=0.0358). These results suggest that caveolin-1 overexpression is associated with tumour progression, thereby indicating a poor prognosis for certain patients undergoing surgical resection for pancreatic carcinoma.     

Apolipoprotein E expression in localized prostate cancers

Although prostate cancer has become the most common solid tumor diagnosed in men and the second leading cause of death due to malignancy, the progression of the disease is still somewhat unpredictable, until it becomes locally advanced or metastatic. The clinical problem to distinguish between dormant and progressive cancers is essential to patient care, as surgical and medical therapies have significant risk of morbidity and disability. Multiple gene expression in prostate cancer was surveyed by differential display cloning between the undifferentiated hormone refractory human prostate cancer cell line PC-3 (highly tumorigenic in nude mice) the hormone responsive LNCaP cell line (weakly tumorigenic in nude mice), and the poorly differentiated DU-145 cell line (moderately tumorigenic). ApoE mRNA was found to be highly expressed only in PC-3 cell-line. We further examined its protein expression by immunohistochemistry in 20 prostatectomy specimens and an association between Gleason score for each sample and ApoE expression was determined. ApoE expression correlates directly with the Gleason score in tissue sections, hormone independence as well as local and distant invasiveness. Prostatic intraepithelial neoplasias (PINs) adjacent to clinically manifested cancer were positive whereas more distant PINs were negative for ApoE. ApoE may represent a marker of more aggressive cells in human prostate cancers.     

DNA ploidy and prostate-specific antigen as prognostic factors in clinically resectable prostate cancer.

Prostate-specific antigen (PSA) and DNA ploidy as measured by flow cytometry were compared with conventional prognostic indicators in 112 patients who underwent radical prostatectomy for clinically resectable prostate cancer. The variables examined included age, race, prostatic acid phosphatase (PAP), Gleason score of the radical prostatectomy specimen, and pathologic stage. No significant relationships were found between DNA ploidy and age, mean PAP value, and absolute PAP value. Of the 112 patients, 65 (58.0%) had disease limited to the prostate (pathologic Stages A and B); 47 (42.0%) had extraprostatic disease (pathologic Stages C and D1). The stage was related to the Gleason score (P less than 0.0001) where extraprostatic disease was associated with a Gleason score of 6 to 10. Nineteen (17.0%) patients had aneuploid tumors, and 93 (83.0%) had diploid tumors. DNA ploidy significantly correlated with pathologic stage (P = 0.04); aneuploidy was identified more frequently in patients with Stages C and D1 tumors. Aneuploid tumors occurred more frequently than diploid tumors in patients with a Gleason score of 6 to 10 (P = 0.034). Mean PSA values were higher in patients with aneuploid tumors (P = 0.078), extraprostatic neoplasms (P = 0.00001), and cancers with a Gleason score of 6 to 10 (P = 0.0004). Furthermore, PSA values greater than 10.0 ng/ml were associated with extraprostatic disease and a Gleason score of 6 to 10 (P less than 0.05 and P less than 0.001, respectively). Significant racial differences were found with respect to DNA ploidy, mean DNA indices, and mean PSA values. The 18 black patients had more DNA aneuploid tumors (P = 0.043), a higher mean DNA index (P = 0.017), and a higher mean PSA value (P = 0.043) than the 94 white patients. Both PSA and DNA ploidy analysis by flow cytometry appear to be valuable indicators in the evaluation of patients with prostatic carcinoma.     

Ten-year survival after radical prostatectomy: specimen Gleason score is the predictor in organ-confined prostate cancer

Pathologic stage is a major prognostic factor in patients with clinically localized prostate cancer. However, disease recurrence occurs even in patients with organ-confined disease. With the advent of prostate-specific antigen (PSA) testing, the percentage of patients with pathologically organ-confined tumors has increased significantly. We studied clinical/pathologic factors that will predict disease recurrence in patients with pathologically organ-confined tumors. Patients with clinically localized newly diagnosed prostate cancer who had not received prior therapeutic intervention but who underwent radical prostatectomy as definitive treatment between 1990 and 1999, were included in this study. Clinical/pathologic parameters including age, race, clinical stage, preoperative PSA, and biopsy and specimen Gleason scores (grouped as 2-6, 7, and 8-10) were correlated with disease-free survival in patients with organ-confined disease. Metastasis-free and cancer-specific survival for the cohort was also assessed. A total of 1045 patients fulfilled our inclusion criteria. Overall, the 10-year estimates of PSA progression-free, metastasis-free, and cancer-specific survival were 75%, 91%, and 92%, respectively. Cancer was confined to the prostate in 532 of 1045 patients (51%), of whom 96% (511 of 532) remain PSA progression-free, compared to 65% (335 of 513) with extraprostatic disease (P = 0.0001). Interestingly, in patients with organ-confined disease, the specimen Gleason score was the only prognostic factor for disease recurrence after multivariable analysis. Radical prostatectomy provided excellent cancer control. For patients with pathologically organ-confined tumors, the specimen Gleason score is the only factor predictive of disease-free survival. Of note, Gleason scores of 8-10 are uncommon in these patients.     

Implications of greater short-term PSA recurrence with laparoscopic as compared to retropubic radical prostatectomy for Japanese clinically localized prostate carcinomas

Purpose: There is ongoing discussion as to the necessity for certain surgical procedures being limited to high through-put institutions. To cast light on this question regarding use of open as compared to laparoscopic radical prostatectomy (LRP) the present study was conducted focusing on biochemical (PSA) recurrence-free survival of Japanese patients with clinically localized prostate carcinomas. Materials and Methods: From April 2004 to December 2010 we identified 579 patients undergoing LRP (n=245) and retropubic radical prostatectomy (RRP) (n=334) who did not undergo immediate adjuvant therapy (radiation and/or hormonal) and whose PSA levels were lower than 25 ng/ml. Preoperative prostate specific antigen (PSA) level, clinical stage, biopsy Gleason score and pathological features were assessed and Kaplan-Meier estimates of biochemical recurrence (BCR)-free survival were compared. A Cox regression model analysis was performed to determine predictors of biochemical recurrence. Results: Median follow up was 35 months(2- 115). On univariate analysis the LRP group had a slightly lower pathological T stage (p<0.001), higher biopsy Gleason score (p<0.001), but much more organ confined disease (p=0.001) than the RRP group. BCR-free survival did not significantly differ between LRP and RRP groups with preoperative PSA <6, clinical stage T1c,T2a, pathological stage T3 or more, biopsy Gleason score of 8 or more, pathological Gleason score of 6 or less and 8 or more, extra-capsular extension and negative surgical margin. The 3-year BCR-free survival rates were 91.0%(RRP) and 82.2%(LRP) (p<0.001). Conclusion: We conclude that in general LRP may be associated with a less positive outcome than BCR for resection of low risk prostate cancers. Therefore indications for LRP should be very carefully monitored.     

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.     

The expression of metallothioneins on imprint smears of prostate carcinoma: correlation with clinicopathologic parameters and tumor proliferative capacity

AIMS AND BACKGROUND: Metallothioneins are a family of metalbinding cysteine-rich proteins that play an important role in cellular processes such as proliferation and apoptosis, protection against oxidative stress and metal ion homeostasis and detoxification. Recent findings suggest that metallothioneins might play a significant role in the development and progression of prostate cancer. It has been also demonstrated that Ki67 expression may have prognostic value for disease-free survival in cases of prostate carcinoma. STUDY DESIGN: Imprint smears samples obtained from 70 patients immediately after radical prostatectomy for prostatic carcinoma were immunostained with monoclonal antibodies against metallothioneins and Ki-67. Metallothionein expression was correlated with Ki-67 immunostaining, Gleason score, stage, preoperative prostate-specific antigen levels and biochemical recurrence. RESULTS: Metallothionein expression was shown to correlate strongly with Gleason score (P < 0.001) and significantly with pathological staging and Ki-67 immunostaining (P < 0.001, P < 0.05, respectively). In contrast, no significant association between metallothioneins and preoperative PSA was demonstrated. Both of the studied markers (metallothioneins and Ki-67) correlated with recurrence (P = 0.009, P = 0.006, respectively). CONCLUSIONS: The present findings support the independent predictive value of metallothioneins and Ki-67 in prostate cancer. However, additional data are needed in order to reveal the factors that influence the expression of metallothioneins in epithelial neoplastic cells and clarify their mechanism of action.