SNAI1 and neoplasm: The role of Snail and Slug in the drug resistance of tumor cells is associatedwith a repression of the genes of the pro-apoptotic PUMA, ATM, PTEN, p53, BID,and caspase-6 proteins and de-repression of the genes of the proteinsassociated with the stemness phenotype [52, 55, 57].