CSC properties include the ability to self-renew, formation of tumorspheres in nonadherent culture conditions, expression of specific cell surface receptors (such as CD44 and CD133 in HNSCC), expression of transcription factors related to pluripotency (Nanog, Sox-2, and Oct-3/4), and high expression of ABC transporters. This evidence concerns the gene SOX2 and head and neck squamous cell carcinoma.