The promoter hypermethylation of RARB could inhibit the gene expression when added to the methylation inhibitor and deacetylation inhibitor like 5′-aza-2′-deoxycytidine (5-aza-dC) and trichostatin A (TSA) which could recover the gene expression and inhibit tumor cells growth [36, 39]. This evidence concerns the gene RARB and neoplasm.