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Polyoma (BK) virus-type cellular changes are occasionally reported in urine specimens, yet rarely detected in histologic sections of bladder biopsies. A total of 762 predominantly voided urine specimens with a cytologic diagnosis of polyoma virus-type change were retrieved from the cytopathology files of the Johns Hopkins Hospital over a 15-year period (1988-2003). Biopsies were available for 33 cases (29 patients) following or preceding the urinary cytology (mean interval, 210 days). The biopsies originated primarily from bladder (n=31) with one biopsy each from renal pelvis and urethra. Representative paraffin blocks were chosen from each case for immunoperoxidase staining with SV40 large T antigen. There were 22 males and 7 females with an age range of 34 to 79 years (mean, 64.7 years). The histologic diagnoses of the 33 tissue biopsies were: benign urothelium (n=9), urothelial carcinoma (n=21) and 1 case each of dysplasia, small cell carcinoma, and chronic lymphocytic leukemia involving lamina propria of the bladder. Only 3 of 33 biopsies on hematoxylin-stained sections showed morphologic changes of polyoma virus, which lacked sufficient tissue to perform immunohistochemistry for SV40 large T antigen (LTag). Immunohistochemical staining for LTag was positive in 7 cases. Only 2 cases showed strong/diffuse and moderate/focal staining for LTag with both representing invasive high-grade urothelial carcinoma (where no inclusions were seen on hematoxylin and eosin-stained sections) and both demonstrating positive immunostaining for p53. One of these 2 cases was from an organ transplant recipient and the other from a patient with no known immunosuppression. Our data lead to the following conclusions: 1) cytology appears to be more sensitive than histology in detecting cells with polyoma virus; 2) cytohistologic discordance might be due to: a) polyoma (BK) virus infected cells are shed from the tissue and collected in the urine; b) polyoma virus changes may be focal and not sampled in directed tissue biopsies; c) polyoma virus changes may originate from sites in the genitourinary tract other than the bladder; d) the lack of a "gold standard" to confirm the cytologic diagnoses of polyoma virus; and e) the discordance in time between the biopsy and cytology specimens in the current retrospective study. 3) Because some cytologically benign cases of polyoma virus were associated with malignant biopsies, careful morphologic evaluation is required to avoid false-negative urinary cytology samples. This investigation further examined the immunohistochemical staining pattern for SV40 LTag and p53 in noninvasive low-grade papillary urothelial carcinoma using a tissue microarray constructed from bladder biopsies of 79 randomly selected patients. Weak LTag staining was present in occasional neoplastic urothelial cells of 2 patients. The staining was present in only one of four samples from each tumor (0.63%; 2 of 316 tumor spots), which further illustrates the patchy and focal presence of virion containing cells. p53 staining in...

Our data suggest that epigenetic alterations may have an important role in the mechanism of bladder tumor recurrence. Analysis in a larger cohort is needed to further assess our current preliminary findings of the role of gamma-H2AX expression for predicting outcome in low grade urothelial carcinoma cases.

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203 Background: MicroRNAs (miRNA) are small, noncoding nucleic acids that regulate expression of genes. Altered expression of miRNA has been implicated as a factor in carcinogenesis. We previously demonstrated 27 miRNA with differential expression that varied greater than two-fold between areas of benign and cancerous prostate glands in 64 patients. The goal of this study was to validate these findings in a selected group. Methods: RNA was extracted from prostate cancer foci and areas of benign glands from paraffin embedded prostatectomy specimens from 29 selected patients. Five patients each were selected with Gleason 3+3, 3+4, 4+3, and 4+4 or higher. The remaining nine selected patients went on to develop metastatic disease. Expression profiles for 577 miRNA were analyzed using Taqman OpenArray. Data analysis was performed using the mean-centering method for normalizing miRNA across the original and validation cohorts. Results: Significant overlap was found between the original and validation cohorts for miRNA that were upregulated at least two-fold between benign and cancerous glands (p<0.05). There were no differences in miRNA expression between T2 and T3 cases. Comparison of Gleason 6 vs Gleason 8+ showed significant difference in expression of mir-185, mir106b, and mir-181a. Interestingly, among the subset of patients that developed metastatic disease, the benign prostate glands demonstrated significant overexpression of mir-21 as compared to the benign glands of the localized cohort. Mir-21 is a known oncomir shown to be overexpressed in other metastatic tumors. Conclusions: This study validates our findings on differential expression of miRNA between cancerous and benign glands. There was a significant difference in expression of three miRNAs between Gleason 6 and 8 cancers, and no differences were found between T2 and T3. miRNA may represent a unique signature in the benign glands of patients with metastatic disease.