SiRNA is a powerful toolin reversing chemoresistance of cancer cells by down-regulation ofoncogene factors, such as Survivin, Bcl-xl, and Mcl-1.7,8 Thus, understanding the mechanisms involved in drug resistance canhelp render anticancer therapy more efficacious.9 Another issue in anticancer therapy is the low efficacyof monotherapy in the eradication of cancer cells.10 These difficulties have spurred scientists toward developingco-delivery strategies for anticancer therapy. This evidence concerns the gene MCL1 and cancer.