CD44 and endometriosis: Moreover, CECs isolated from patients with extra-uterine endometriosis using cmHsp70.1 mAb beads, in contrast to EpCAM mAb beads, could be cultured, remaining viable for several months, and were positive for the typical CTC marker cytokeratin and the mesenchymal stemness markers CD44 and CD105, but were negative for the leukocyte marker CD45.