Depending on the tissue where the CaSR is expressed, the CaSR can either promote cancer development, thus behaving as an oncogene, such as in gastric, breast, prostate, and renal cancer, or as a tumor suppressor, such as in colorectal, endometrial, parathyroid cancer, and neuroblastoma (Tennakoon et al., 2016). The gene discussed is CASR; the disease is malignant tumor of parathyroid gland.