Given the different conclusions reached in separate studies as to which, if any, single marker enriches for pancreatic TICs, we sought to determine whether high ALDH activity is a primary determinant of at least a subset of pancreatic TICs and the sufficiency of ALDHhigh and ALDHlow cell populations for tumor-initiation when enriched or depleted of cell populations also expressing CD133. Here, PROM1 is linked to neoplasm.