Alanine to Serine Variant at Position 986 of Calcium Sensing Receptor and Colorectal Cancer Risk

Background: With regard to the effect of calcium against colorectal cancer (CRC) and considering the key role of calcium sensing receptor (CaSR) in calcium homeostasis, this study investigated whether CaSR gene rs1801725 or A986S variant was associated with susceptibility to CRC risk. Methods: This study was conducted as a case-control study and 303 cases with CRC and 354 controls were enrolled. All 657 subjects were genotyped for CaSR gene A986S variant using PCR-RFLP method. Results: No significant difference was observed for the A986S variant of CaSR gene in either genotype or allele frequencies between the cases and the controls and this lack of difference remained non-significant even after adjustment for age, BMI, sex, smoking status, and family history of CRC. No evidence for the effect modification of the association A986S variant and CRC by BMI, sex, or tumor site was also observed. Furthermore, the risk of obesity in relation to the A986S variant in the controls and the cases was separately analyzed and we observed no significant difference between normal weight (BMI < 25kg/m2 ) and overweight/obese (BMI ≥ 25kg/m ) subjects. Conclusions: Our findings do not support a role for effect of the CaSR gene A986S variant on CRC risk; nevertheless, this finding requires confirmation and the role of the gene variant in carcinogenesis needs to be further investigated.