Curiously, in several case studies of cancer patients receiving treatments for immune check point inhibitors, a well-established anticancer treatment that restores immune reactivity against cancer cells, the patients manifested hypocalcemia and hypoparathyroidism, which could be ascribed to the presence of CaSR-specific autoantibodies found in the sera (Piranavan et al., 2019; Trinh et al., 2019; Dadu et al., 2020; Lupi et al., 2020). This evidence concerns the gene CASR and cancer.