SLC25A18 and lung carcinoma: Patients with expressing the Gc2 isoform of GC protein benefit from high circulating vitamin D concentration in lung cancer[44] or colorectal adenoma.[45] Some investigations have observed no association between circulating GC protein level and the risk of urinary bladder cancer[46] or prostate cancer.[47] However, most of these researches have focused on the predictive value of circulating GC, which acted as vitamin D transporter, with significantly less attention given on the cellular GC protein.