Some DDIs might be more significant based on the status of certain organ functions (eg, renal clearance, hepatic function, or short bowel), patient’s genetic composition (eg, genetically determined CYP2D6 activity, with patients exhibiting different metabolizer phenotypes),70 patient’s sex (eg, lipophilic drugs exhibit prolonged action in fatty tissue, which is relevant for most females who usually have a higher percentage of body fat) and specific populations (eg, QT prolongers, older patients or patients with late-stage cancer). Here, CYP2D6 is linked to cancer.