First, we used flow cytometry to evaluate the basal levels of cytokeratin and EpCAM on the surface of human prostate cancer cell lines (PC3, DU145, LNCaP, and C4- 2B), with leukemia cell lines (RCH-ACV, 697, Nalm6 and RS4;11) as controls. The gene discussed is EPCAM; the disease is prostate carcinoma.