Compared to many other tumor types previously exposed to HDAC inhibitors in the Dent laboratory, e.g. breast cancer; liver cancer; pancreatic carcinoma; sarcoma; renal carcinoma; glioblastoma; the PDX and established mutant B-RAF melanoma isolates tested in our studies were highly sensitive to being killed by HDAC inhibitors as single agents at clinically relevant concentrations. Here, HDAC9 is linked to breast cancer.