ITGA6 and posterior cortical atrophy: To characterize these epithelial cells, we performed flow cytometry to analyze the expression levels of epithelial markers (EpCAM, CD49f) and prostate-specific biomarkers (PSMA, PSA, AR) in three different primary donor samples, as well as several PCa cell lines with known expression patterns (LNCaP, LAPC4, DU-145), for comparison (Fig. 4A and Supplementary Fig. 4).