Studies on the role of BMAL1 in orchestrating cancer chemoresistance have provided rather controversial results showing the ability of BMAL1 protein to either protect or sensitize cancer cells to cytotoxic insults induced by different chemotherapy agents in diverse cancer types, which requires further investigation as to assess whether the influence of BMAL1 protein expression on the treatment outcome in cancer is therapy- or tumor type-specific. This evidence concerns the gene BMAL1 and cancer.