Meta-analysis of vitamin D-binding protein and cancer risk
A partir de données de 28 études, cette méta-analyse évalue l'association entre le niveau sérique de la protéine de liaison à la vitamine D et le risque de cancer
Background: Epidemiologic evidence supported a role for vitamin D and vitamin D receptor (VDR) polymorphisms in cancer risk. Beyond VDR, the biological effects of vitamin D are mediated by the vitamin D binding protein (DBP), a key protein in vitamin D metabolism. Furthermore, the gene encoding the DBP (GC, Group-specific component) has an important role in vitamin D pathway. Several studies investigated DBP serological levels and GC polymorphisms in association with cancer risk with controversial results. Thus we carried out a meta-analysis to investigate these associations. Methods: We included 28 independent studies concerning: basal cell carcinoma, bladder, breast, colon-rectum, endometrium, liver, esophagus, stomach, melanoma, pancreas, prostate and kidney. Through random effect models we calculated the Summary Odd Ratios (SORs) for serum DBP and the GC polymorphisms rs2282679, rs12512631, rs7041, rs4588, rs17467825, rs1155563 and rs1352844. Results: We found a borderline decrease in cancer risk for subjects with high compared to low levels of DBP (SOR;95%CI:0.75;0.56-1.00). Dose-response meta-analysis indicate a non-significant decrease risk for an increase of 1,000 nmol/L of DBP: (SOR;95%CI:0.96;0.91-1.01). We found no significant alterations in cancer risk for subjects carrying any of the studied GC polymorphisms compared to wild-type subjects both in the main analysis and in analyses stratified by cancer type and ethnicity. Conclusions: We found trends toward significance suggesting a role of DBP in cancer etiology, that should be confirmed in further studies. Impact: To our knowledge, this is the first study to investigate GC polymorphisms and DBP serological levels in association with any type of cancer.