DRD4 and cancer: The VNTR in the third intracellular loop region of DRD4 typically comprises four or seven tandem repeats, with fewer repeats potentially indicating functional deficiencies or disease predisposition.[46, 47] Although DRD4 VNTR polymorphism has been associated with attention‐deficit hyperactivity disorder,[47] abnormal personality traits,[48] susceptibility to addiction,[49] and Alzheimer's disease,[50] no previous studies have linked the VNTR region of DRD4 to cancer.