PROM1 and ovarian neoplasm: Later on, Silva et al demonstrated that as few as 11 enriched ALDH+CD133+ CSCs isolated from human ovarian tumors were sufficient to initiate tumors in mice and that the presence of ALDH+CD133+ cells in debulked primary tumor specimens correlated with reduced disease-free survival (DFS) and OS in OC patients, indicating that both ALDH and CD133 can be used as a functionally significant set of markers to identify OCSCs [62].