Differences in the expression of the phosphatase PTP-1B in patients with localized prostate cancer with and without adverse pathological features.

Introduction: Patients with adverse pathological features (APF) at radical prostatectomy (RP) for prostate cancer (PC) are candidates for adjuvant treatment. Clinicians lack reliable markers to predict these APF preoperatively. Protein tyrosine phosphatase 1B (PTP-1B) is involved in migration and invasion of PC, and its expression could predict presence of APF. Our aim was to compare PTP-1B expression in patients with and without APF, and to explore PTP-1B expression as an independent prognostic factor. Methods: Tissue microarrays (TMAs) were constructed using RP archival specimens for immunohistochemical staining of PTP-1B; expression was reported with a standardized score (0-9). We compared median PTP-1B score between cases with and without APF. We constructed two logistic regression models, one to identify the independence of PTP-1B score from biologically associated variables (metformin use and type 2 diabetes mellitus [T2DM]) and the second to seek independence of known risk factors (Gleason score and prostate specific antigen [PSA]). Results: A total of 73 specimens were suitable for TMA construction. Forty-four (60%) patients had APF. The median PTP-1B score was higher in those with APF: 8 (5-9) vs 5 (3-8) (p=0.026). In the logistic regression model including T2DM and metformin use, the PTP-1B score maintained statistical significance (OR 1.21, 95% CI 1.01-1.45, p=0.037). In the model including PSA and Gleason score; the PTP-1B score showed no independence (OR 1.68, 95% CI 0.97-1.41, p=0.11). The area under the curve to predict APF for the PTP-1B score was 0.65 (95% CI 0.52-0.78, p=0.03), for PSA+Gleason 0.71 (95% CI 0.59-0.82, p=0.03), and for PSA+Gleason+PTP-1B score 0.73 (95% CI 0.61-0.84, p=0.001). Discussion: Patients with APF after RP have a higher expression of PTP-1B than those without APF, even after adjusting for T2DM and metformin exposure. PTP-1B has a good accuracy for predicting APF but does not add to known prognostic factors.

Atypical small acinar proliferation: utility of additional sections and immunohistochemical analysis of prostatic needle biopsies.

BACKGROUND: In surgical pathology, atypical small acinar proliferation is commonly detected in prostate biopsies. Most studies on atypical small acinar proliferation have examined morphological characteristics and the utility of immunohistochemical studies. However, these resources are not available to many pathology departments. We have found that examining additional sections is a simple and inexpensive method that allows better evaluation of focal prostatic glandular atypia. OBJECTIVES: The present report compares the diagnostic utility of immunohistochemical techniques versus examining additional sections in prostate biopsies with focal glandular atypia. PATIENTS AND METHODS: Thirty recently studied prostate biopsies with focal glandular atypia were selected. In each case, 3 additional levels were examined. An immunohistochemical study was performed on one level using an antibody against high-molecular-weight keratin (34BetaE12). Two additional sections were stained with hematoxylin and eosin. RESULTS: The diagnosis of focal carcinoma was established with only additional sections in 4 cases (13.3%). In 2 of these biopsies, additional areas of carcinoma were found that were not identified in the original sections. In 4 other cases, immunohistochemical analysis was the only useful method for diagnosing cancer. In 9 cases (30%), both methods were useful for classifying focal glandular atypia as carcinoma. In the remaining 13 cases,neither immunohistochemical analysis nor additional sections were useful in changing the diagnosis of focal glandular atypia. CONCLUSIONS: Focal glandular atypia in prostatic needle biopsies should be routinely examined with additional sections, particularly when immunohistochemical analysis is not possible. Some biopsies with atypical glandular proliferation may show focal carcinoma in additional sections, even if the immunohistochemical analysis did not provide a diagnosis of malignancy. Additional sections can also reveal areas of carcinoma that were not apparent in the original sections.