CASP3 and squamous cell carcinoma: These results are consistent with the mechanism observed in previous studies: 3-HBI upregulated p53, Bax, cytochrome c, caspase-3, and caspase-9 and downregulated Bcl-2 in lung cancer A-549 cells [19], the same upregulated Bax, caspase-3, and downregulated Bcl-2 in squamous cell carcinoma SCC15 cells [17].