CASP9 and cancer: The results from the 12 research papers short-listed in this scoping review suggest that both γT3 and δT3 have potent anticancer effects and these T3 analogues exert anticancer effects through three major pathways, i.e., apoptosis (BIRC3, BIRC5, CASP8, CASP9, and PARP1), transcriptional dysregulation in cancer (CDKN1A, CDKN1B, MMP9, MYC, JUN, and RELA), and cancer progression (CASP3, CCND1, CTNNB1, VEGFA, and WNT1) pathways.