The susceptibility of APOE4-positive cancer survivors to CICI is supported by preclinical studies: compared to APOE3, APOE4 knock-in mice have an increased sensitivity to chemotherapy-induced behavioral impairment in spatial learning at 6 months of age (Speidell et al., 2019) and 12 months of age (Demby et al., 2020). Here, APOE is linked to cancer.