The above results suggested that GTPs-induced inhibition or reduction in cell viability of melanoma cells was associated with the reduction in the expression of HDAC proteins; we further examined the effects of valproic acid, a well known inhibitor of HDAC, on the viability and death of melanoma cells to verify that the action of GTPs is similar to that of HDAC inhibitor. The gene discussed is HDAC9; the disease is melanoma.