Notably, also based on recent findings that various molecules containing the tin metal in their structure could exhibit potential anti-cancer activity causing a caspase-3 dependent cell death [34], our study aimed to investigate the in vitro activity toward HTLV-1-infected cells of a synthetic compound containing the tin molecule linked to three butyls and a trifluoroacetate chosen as the prototype for this study. This evidence concerns the gene CASP3 and cancer.