Several well-known mechanisms may contribute to drug resistance in cancer, such as apoptosis inhibition (Qie and Diehl 2016), drug inactivation (Mansoori et al. 2017), multi-drug resistance (MDR) via different ATP-binding cassette (ABC) transporters (e.g., ABCB1, ABCG2, ABCB4, ABCC15, ABCC10, and ABCG4) (Fletcher et al. 2016), cell cycle modulators (e.g., c-myc and cyclin D1) (Christowitz et al. 2019), and the autophagy pathway (Desantis et al. 2018; Hombach-Klonisch et al. 2018). The gene discussed is ABCG2; the disease is cancer.