CASP9 and lip and oral cavity carcinoma: Consistently, in HSC‐3 cells, HO‐3867 reduced the pro form of caspase 8, caspase 9, caspase 3 and PARP, and enhanced the active form of caspase 8, caspase 9, caspase 3 and PARP (Figure 5C,D) These results imply that HO‐3867 induces apoptotic pathway through caspase pathway in human oral cancer cells.