CD44 and breast carcinoma: Based on the studies discussed above, it is striking to see how heterogeneous are the sets of putative OCSC markers used by different groups, especially if compared with other tumor types where there is a more general consensus on the CSC-associated repertoire of surface antigens (e.g., CD44+/CD24- in breast carcinoma, LGR5+ in colon carcinoma, CD133+ in glioblastoma).