However, in several tumor cell lines such as human leukemia cells [43] and colon cancer cells [44] JNK/c-Jun is activated by HDACIs to promote apoptosis, and HDAC inhibition-induced ERK activation contributes to early M-phase (prometaphase) arrest and subsequent apoptosis in prostate cancer cell LNCaP [45]. This evidence concerns the gene HDAC9 and prostate cancer.