Sox2, a marker for stem-like tumor cells in skin squamous cell carcinoma and hedgehog subgroup medulloblastoma.

Heterogeneity within tumors is becoming increasingly recognized as an important cause of treatment failure in cancer. Two recent studies use fate-mapping and limiting dilution transplantation assays to identify SRY (sex determining region Y)-box 2 (Sox2) as cancer stem-cell marker and driver of cancer stemness.