Our research group has discovered that the BDNF Val66Met polymorphism is associated with a lower risk of developing self-perceived CRCI in breast cancer patients [7], where carriers of the Met allele had lower odds of reporting subjective CRCI in the cognitive domains of verbal ability (OR = 0.34, 95% CI = 0.12–0.90) and multitasking (OR = 0.37, 95% CI = 0.15–0.91). The gene discussed is BDNF; the disease is breast cancer.