PROM1 and neoplasm: The unusual high expression of the stemness markers CD133 and CD105 is probably related to the fact that RCC-41 is an undifferentiated tumor [48] and points out the likely existence in RCC-41-P-0 of a large proportion of very primitive CSC-like cells, while the expression of E-cadherin supports the presence of differentiated non-CSC tumor cells [21, 49, 50].