Cytochromes P450 enzymes, especially CYP3A4, are responsible for metabolizing a broad range of anticancer drugs. Combination
therapy is common in patients with cancer, which may cause potential drug drug interactions (DDIs) leading to increased risk of
side-effects/toxicity or decreased effectiveness. The review summarizes CYP3A4-mediated DDIs, with anticancer drugs as CYP3A4 substrates
or modulators, in clinical trials during cancer therapy and aims to increase clinicians' awareness to take caution to reduce the risk.