SNAI1 and head and neck carcinoma: For example, Twist, which is an inducer of EMT, prevents tumor senescence,23 and overexpression of Twist enhances in vitro tumor‐sphere formation and in vitro tumor seeding.22 Similarly, knockdown of Snail, which also induces EMT, reduces tumor‐sphere formation in head and neck carcinoma.42 As mentioned above, some reports have revealed that several cytokines and transcriptional factors that induce EMT also contribute to induction of a CSC phenotype.