PROM1 and prostate cancer: So far, cell surface markers such as CD44, CD133 (prominin-1), Sca-1 (stem cell antigen-1), CD24 (heat-stable antigen), CD29 (integrin β1), CD49f (integrin α6), and ESA (epithelial-specific antigen) have been frequently used for the detection of breast, colorectal, pancreatic, and prostate cancer stem cells (146).