Considering that CRY1 and CRY2 have been associated with p53 suppression or degradation in other cancers (Chan et al., 2021; Jia et al., 2021) and that Cry1 and Cry2 knockout in p53 mutant mice reduces cancer risk (Ozturk et al., 2009), KS15, or its derivatives (Jeong et al., 2021) may be efficacious in the treatment of several cancers, in addition to MCF-7 breast cancer. Here, CRY2 is linked to breast cancer.