PROM1 and cancer: To mimic the clinically relevant pathophysiology of a heterogeneous tumor with a substantial number of cancer cells lacking the targeted antigen, we inoculated nude mice with a mixed population of equal amounts of hCD133+ and hCD133− colon cancer cells, we determined the expression of CD133 in tumor tissues on days 7 and 14 after transplantation of a SW620 and SW480 cell mixture by IHC staining.