The effect of HDAC inhibitor, trichostatin A (TSA), on Nav1.5, nNav1.5, HDAC1, HDAC2, HDAC3, REST, MMP2 and N-cadherin gene expression and on cell motility and migration of the less metastatic human breast cancer cells, MCF-7, were investigated. This evidence concerns the gene HDAC9 and breast carcinoma.