Lung and breast cancer-derived cell lines with or without TOX2 promoter hypermethylation were treated with Vehicle (S for sham), the DNA demethylating agent 5-Aza-2′-deoxycytidne (DAC), or the histone deacetylase inhibitor trichostatin A (TSA) as described to evaluate the contribution of cytosine methylation and chromatin remodeling in silencing this gene. This evidence concerns the gene TOX2 and breast carcinoma.