Non-cancer therapy consisted of ondansetron (CYP2D6—CPIC Level A) for nausea, as well as morphine (OPRM1, COMT—CPIC level C) and tramadol (CYP2D6—CPIC Level A, FDA Tier 1; OPRM1, COMT—CPIC level C) for pain management. This evidence concerns the gene CYP2D6 and cancer.