CD34 immunohistochemical assessment of angiogenesis as a prognostic marker for prostate cancer recurrence after radical prostatectomy.

PURPOSE: We assess the neovascularity of clinically localized prostate cancer by immunohistochemistry using the monoclonal antibody CD34 in an attempt to identify associations between angiogenesis and disease progression following radical prostatectomy. MATERIALS AND METHODS: Microvascularity was evaluated using the CD34 monoclonal antibody in archival paraffin embedded radical prostatectomy specimens from 149 patients followed from 3 to 10 years (mean 6.6). Vessels were quantified by counting a minimum of 2 selected microscopic fields (200x, 0.754 mm.2) from each tumor, area of prostatic intraepithelial neoplasia and prostatic hyperplasia, and given a numerical value representing the microvessel density count. RESULTS: Mean microvessel density count did not vary significantly with age or race. There was a significant association between the count and nuclear grade, Gleason sum and pathological stage. Cox survival analysis shows that microvessel density is significantly related to time to recurrence when considered as a continuous variable (p=0.03) as well as dichotomous variable (p=0.007) (microvessel density count less than 90 and 90 or greater). The 5-year recurrence-free survival was significantly higher for patients with a count less than 90 (71%) than for those with a count 90 or greater (51%) (p=0.006). The 5-year recurrence-free survival was also significantly different when microvessel density was used as a continuous variable (p=0.02). Controlling for stage, Gleason sum, race and nuclear grade, microvessel density remained significant in predicting recurrence (p=0.03) but when pretreatment prostate specific antigen was included in the model the count was no longer significant. The microvessel density count in the tumor area significantly increased with increasing Gleason sum and nuclear grade but it did not increase significantly in the adjacent benign prostate or areas of prostatic intraepithelial neoplasia in the same specimen. CONCLUSIONS: Microvascularity or neovascularity as measured by the CD34 antigen may be a prognostic marker of recurrence for prostate cancer patients after radical prostatectomy but more study in prostate specific antigen era patients with sufficient followup is needed.

The effect of human chorionic gonadotropin on methotrexate concentration in the rat testes.

PURPOSE: We analyzed the effect of human chorionic gonadotropin (hCG) on drug concentrations in testicular interstitial fluid and whole testis tissue samples in rats receiving hCG prior to methotrexate (MTX) administration and in animals that did not receive hCG. MATERIALS AND METHODS: Adult male Sprague-Dawley rats were injected subcutaneously with 200 i.u. hCG (Goldline Laboratories, Ft. Lauderdale, FL.). Controls were injected subcutaneously with normal saline (0.2 cc). Sixteen hours after injection, each rat was given methotrexate (Methotrexate LPF, Immunex Corp. Seattle WA.) via a carotid artery cannula in a dose of 30 mg./kg. Methotrexate (MTX) levels were collected 60 minutes post infusion time in 27 rats and 90 minutes post infusion in 27 rats. MTX levels were measured in serum, testicular interstitial fluid and testicular tissue. MTX levels were measured using high performance liquid chromatography (HPLC). RESULTS: A significantly higher concentration of MTX was found in testicular interstitial fluid (TIF) in rats injected with hCG when specimens were collected 60 minutes post infusion. MTX levels in TIF had reversed 90 minutes post infusion with higher levels found in control rats. Tissue levels of MTX demonstrated no significant difference at either 60 or 90 minutes in the hCG treated animals or controls. CONCLUSION: Our results suggest that hCG effects the tissue distribution of MTX within the testis. Human chorionic gonadotropin may have this effect on the testicular microvasculature by 1) selectively increasing capillary permeability, 2) increasing lymphatic flow within the testes or 3) increasing testicular blood flow.

Biostatistical modeling using traditional variables and genetic biomarkers for predicting the risk of prostate carcinoma recurrence after radical prostatectomy.

BACKGROUND: Approximately 50-60% of patients treated with radical prostatectomy for clinically localized prostate carcinoma are found to have microscopic disease that is not organ-confined, and a significant portion of these patients will relapse. Multiple studies have attempted to identify these high risk patients by evaluating many potential prognostic variables. These studies, however, have not included the more recent molecular biomarkers found to be independent predictors of disease recurrence. METHODS: One hundred thirty-two patients who underwent radical prostatectomy at one center between 1986 and 1993 were subjected to a multivariable Cox regression analysis to determine the preoperative and postoperative variables that remain significant predictors for the likelihood of serologic recurrence. The preoperative variables included in the model were age, race, and prostate specific antigen(PSA); the postoperative variables were Gleason sum, nuclear grade, pathologic stage (capsular status), p53 tumor suppressor gene expression, bcl-2 protooncogene expression, and proliferative biomarker Ki-67 expression. Biomarkers were also evaluated separately. RESULTS: A model was developed using only variables that remained significant predictors for the likelihood of recurrence. The following equation calculated the relative risk of recurrence: Rw = exp [(0.70 x Race) + (0.79 x PSA[4.1-10]) + (1.34 x PSA[>10]) + ( 0.91 x Organ confinement) + (0.65 x p53[1,2+]) + (1.45 x p53[3,4+]) + (0.70 x bcl-2)]. This equation categorized men into 3 distinct risk groups (low: Rr < 5.0; intermediate: Rr = 5.0-15.0; high risk: Rr > 15.0). CONCLUSIONS: This equation allows patients at high risk for PSA recurrence to be identified shortly after radical surgery. These patients at high risk for serologic recurrence and eventual progression may be considered for currently accepted adjuvant therapy or enrollment in clinical trials for the newer investigational therapies for locally advanced prostate carcinoma.

Ki-67 expression is a prognostic marker of prostate cancer recurrence after radical prostatectomy.

PURPOSE: We assessed the cellular proliferation of clinically localized prostate cancer by immunohistochemistry using the monoclonal antibody MIB to Ki-67 antigen in an attempt to identify associations between proliferative indexes and disease progression following radical prostatectomy. MATERIALS AND METHODS: Ki-67 proliferative antigen was evaluated using MIB 1 monoclonal antibody in archival paraffin embedded radical prostatectomy specimens from 180 patients followed for 1 to 9 years (mean 4.4). The percentage of tumor nuclei expressing Ki-67 antigen was measured and assigned and MIB 1 score (none or rare--negative, 1+--low score and 2 to 4+--high score) and analyzed for prostate specific antigen, stage, age, race, grade and serological recurrence postoperatively. RESULTS: There was a significant association between MIB 1 score and nuclear grade (p < 0.001), Gleason score (p < 0.001) and pathological stage (p = 0.01). Patients with a high MIB 1 score had earlier progression and a lower 5-year recurrence-free survival rate (44%) than those with negative MIB 1 scores (71%, p < 0.001). In multivariate Cox regression analysis with backward elimination, pathological stage (p < 0.01), pretreatment prostate specific antigen (p = 0.04) and MIB 1 score (p = 0.05) were statistically significant predictors of disease-free survival, and patients with a high MIB 1 score were 3.1 times as likely to have recurrence as those with a negative score. Controlling for stage, patients with organ confined disease and a high MIB 1 score had a lower 5-year disease-free survival rate (68%) than those with a low MIB 1 score (95%, p < 0.01). CONCLUSIONS: Proliferative activity as measured by the Ki-67 proliferative antigen, MIB 1, appears to be a prognostic marker of recurrent prostate cancer after radical prostatectomy.

Protein expression of p53, bcl-2, and KI-67 (MIB-1) as prognostic biomarkers in patients with surgically treated, clinically localized prostate cancer.

BACKGROUND: Protein expression in the primary tumor of the tumor suppressor gene p53 and the proto-oncogene bcl-2 have been shown to be prognostic biomarkers of cancer recurrence after radical prostatectomy in patients with clinically localized prostate cancer. Cancer cell proliferation as measured by immunohistochemical markers such as the MIB-1 antibody for Ki-67 has recently been suggested to be of prognostic value in prostate cancer. The goal of this study was to determine the clinical use of p53, Ki-67 (MIB-1), and bcl-2 immunohistochemical protein expression in the primary tumor as combined predictors of disease progression after radical prostatectomy (RP). METHODS: Protein expressions of p53, Ki-67, and bcl-2 were evaluated in archival paraffin-embedded RP specimens from 162 patients monitored from 1 to 10 years (mean, 4.5 years) and correlated to stage, grade, race, and serologic (prostate-specific antigen) recurrence after operation. RESULTS: Expression was detected in 112 (69.1%), 44 (27.2%), and 62 (38.3%) of 162 patients for p53 (1+ or greater), bcl-2 (1+ or greater), and Ki-67 (2+ or greater), respectively. Biomarker expressions were not correlated to age and race; however, all increased with increasing stage and grade. The degree of expression by percentage of malignant cells staining correlated to recurrence for p53 and Ki-67 but not for bcl-2. All three markers were correlated to raw and Kaplan-Meier recurrence by means of univariate analysis with recurrence estimates at 6 years of 60.7% versus 24.2%, 84.2% versus 38.6%, and 72.4% versus 30.6% comparing positive versus negative expression of p53, bcl-2, and Ki-67, respectively. p53 and bcl-2 remained as independent prognostic markers by Cox multivariate regression analysis. Although Ki-67 did not remain an independent marker, it added prognostic use in certain subsets of patients. CONCLUSIONS: p53, bcl-2, and Ki-67 (MIB-1) appear to be important biomarkers to predict recurrence in patients with clinically localized prostate cancer after RP, and all three biomarkers deserve further study.