Snail is one of the major transcription factors governing epithelial-mesenchymal transition (EMT) of various cancer cells, and its increase in tumor tissues of patients is correlated with tumor progression (metastasis and recurrence) in various cancers including melanoma [32–34], hepatocellular carcinoma [35], head and neck squamous cell carcinoma [36], and endometrial cancers [37]. This evidence concerns the gene SNAI1 and melanoma.