The most well-studied of these factors are the transcription Snail family factors (Snail 1 and Snail 2, also known as SLUG), zinc finger E box binding homology frame factors (ZEB1/2), and those of the basic helix-loop-helix (BHLH) family (TWIST1/2) [139]; the collective protein and RNA levels of these factors as well as those of several cell adhesion molecules associated with the epithelial phenotype (e.g., cadherins and vinculin) are often used in cancer biology to determine where on the EMT spectrum a cancer’s phenotype falls and often highly prognostic of clinical outcome [163, 166]. This evidence concerns the gene SNAI2 and cancer.