PROM1 and cancer: We have reported [63] in malignant melanoma that shRNA-mediated downregulation had profound effects on human CD133-expressing cancer cells; in vitro CD133 knockdown slowed cell growth, reduced cell motility, and decreased the formation of spheroids under stem cell-like growth conditions; in vivo the downregulation of CD133 severely reduced the capacity of the cells to metastasize, particularly to the spinal cord [63].