Polymorphic variation in the GC and CASR genes and associations with vitamin D metabolite concentration and metachronous colorectal neoplasia
Menée auprès de 1 439 participants inclus dans deux essais américains, cette étude évalue l'association entre des polymorphismes des gènes GC et CASR, le niveau de vitamine D et le risque de néoplasie colorectale métachrone
Vitamin D levels and calcium intake have been associated with risk of colorectal neoplasia, and genetic variation in vitamin D-pathway genes may affect circulating vitamin D metabolite concentrations and/or risk for colorectal lesions. This study evaluated associations between polymorphic variation in the Gc-globulin (GC) and Calcium-sensing receptor (CASR) and odds for metachronous colorectal neoplasia and vitamin D metabolite concentrations. Methods: Participants from the Ursodeoxycholic Acid (UDCA) and Wheat Bran Fiber (WBF) trials (n=1439) were analyzed using a single nucleotide polymorphism (SNP) tagging approach, with a subset (n=404) of UDCA trial participants for whom vitamin D metabolite concentrations were also available. A total of 25 GC and 35 CASR tagSNPs were evaluated using multiple statistical methods. Results: Principal components analyses did not reveal gene-level associations between GC or CASR and colorectal neoplasia, however, a significant gene-level association between GC and 25(OH)D concentrations (p < 0.01) was observed. At the individual SNP-level and following multiple comparisons adjustments, significant associations were observed between seven GC (rs7041, rs222035, rs842999, rs1155563, rs12512631, rs16846876, rs1746825) polymorphisms and circulating measures of 25(OH)D (adjusted p < 0.01), and CASR SNP rs1042636 and proximal colorectal neoplasia (adjusted p = 0.01). Conclusions: These results demonstrate a possible association between variation in CASR and odds of colorectal neoplasia as well as the potential role of variation in GC with circulating 25(OH)D concentrations. Impact: Additional research is warranted to determine the mechanism of GC genotype in influencing 25(OH)D concentrations and to further elucidate the role of CASR in colorectal neoplasia. ℑ