Evaluation of basal and luminal subtypes of urothelial carcinoma in African American and non-African American patients.

305 Background: African American (AA) patients with urothelial carcinoma (UC) have been known to have a worse prognosis even when corrected for variables such as tumor stage and grade. Analysis of gene expression of several malignancies has resulted in the discovery of molecular subtypes with well-defined intrinsic biology. Recent studies in high grade (HG), muscle-invasive UC have led to the identification of two intrinsic, molecular subsets termed “luminal” and “basal” with characteristics of stages of urothelial differentiation, and that remarkably reflect the luminal and basal-like molecular subtypes of breast cancer. Patients with basal-like UC have a significantly worse overall survival. Methods: A total of 215 HG muscle-invasive UC tumors from the MDACC (n=75) and TCGA (n=140) were used to make intrinsic subtype calls using gene expression profiling (MDACC: DASL [cDNA-mediated Annealing, Selection, extension, and Ligation] and TCGA: RNA seq). Basal and luminal subtype calls were derived using previ...