HDAC9 and melanoma: Class I HDAC inhibitors, such as VPA or MS-275, enhance the sensitivity of melanoma cells to the alkylating agents temozolomide, dacarbazine, and fotemustine by suppressing the double strand break (DSB) repair pathway by decreasing the expression levels of RAD51 and fanconi anemia complementation group D2 (FANCD2) (Krumm et al., 2016).