Molecular Analysis of Low Grade Prostate Cancer Using a Genomic Classifier of Metastatic Potential.

PURPOSE: We determined how frequently histological Gleason 3 + 3 = 6 tumors have the molecular characteristics of disease with metastatic potential. MATERIALS AND METHODS: We analyzed prostatectomy tissue from 337 patients with Gleason 3 + 3 disease. All tissue was re-reviewed in blinded fashion by genitourinary pathologists using 2005 ISUP (International Society of Urological Pathology) Gleason grading criteria. A previously validated Decipher® metastasis signature was calculated in each case based on a locked model. To compare patient characteristics across pathological Gleason score categories we used the Fisher exact test or the ANOVA F test. The distribution of Decipher scores among different clinicopathological groups was compared with the Wilcoxon rank sum test. The association of Decipher score with adverse pathology features was examined using logistic regression models. The significance level of all statistical tests was 0.05. RESULTS: Of men with Gleason 3 + 3 = 6 disease only 269 (80%) had a low Decipher score with intermediate and high scores in 43 (13%) and 25 (7%), respectively. Decipher scores were significantly higher among pathological Gleason 3 + 3 = 6 specimens from cases with adverse pathological features such as extraprostatic extension, seminal vesicle involvement or positive margins (p <0.001). The median Decipher score in patients with margin negative pT2 disease was 0.23 (IQR 0.09-0.42) compared to 0.30 (IQR 0.17-0.42) in patients with pT3 disease or positive margins (p = 0.005). CONCLUSIONS: Using a robust and validated prognostic signature we found that a small but not insignificant proportion of histological Gleason 6 tumors harbored molecular characteristics of aggressive cancer. Molecular profiling of such tumors at diagnosis may better select patients for active surveillance at diagnosis and trigger appropriate intervention during followup.

SOX10 immunohistochemistry in sweat ductal/glandular neoplasms.

BACKGROUND: SOX10 is a newer Schwannian and melanocytic marker that has generated great interest for its relative sensitivity and specificity in the diagnosis of neural crest-derived tumors. Previous studies with SOX10 have shown positive immunohistochemical expression in cutaneous eccrine glands and negative expression in eccrine ducts, apocrine glands and hair follicles. Thus, we hypothesized that some sweat gland tumors of presumed eccrine origin would be positive for SOX10, whereas apocrine-derived sweat gland tumors would not. METHODS: A mouse monoclonal anti-SOX10 (clone BC34: Biocare Medical; Concord, California) immunohistochemical antibody was performed on various sweat gland tumors and basal cell carcinoma. RESULTS: SOX10 showed positivity in spiradenomas (13/13), cylindromas (9/10), hidradenoma papilliferum (10/10), syringocystadenoma papilliferum (8/10), apocrine adenomas (8/10), and negativity in poromas (0/12), syringomas (0/10), and basal cell carcinomas (0/13). There was mixed staining of hidradenomas (6/15). CONCLUSIONS: SOX10 immunohistochemistry may be of utility in distinguishing some of the varying adnexal tumors from each other, and from basal cell carcinoma (BCC), but given the staining of both apocrine and eccrine tumors, does not seem to provide information as to their origins as either eccrine or apocrine tumors.