Previous studies have shown that C-reactive protein (CRP) 1059G/C and 1846G/A polymorphisms may play a role in cancer risk. However, the results from the published studies are conflicting. To derive a more precise estimation of the relationship between CRP 1059G/C and 1846G/A polymorphisms and cancer risk, we conducted a meta-analysis of 21 studies involving a total of 26,634 subjects.

Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association.

No significant association was found between CRP 1846G/A polymorphism and cancer risk. However, a significant association was found between CRP 1059G/C polymorphism and cancer risk (CC vs CG+GG: OR=3.60, 95% CI=1.63–7.92, P_H=0.67; CC vs GG: OR=3.53, 95% CI=1.60–7.77, P_H=0.69). In the subgroup analysis by ethnicity, a significant association was found for the CRP 1846G/A polymorphism among mixed population. Interestingly, when stratifying by cancer type, marginally increased risks were observed for CRP 1846G/A polymorphism in colorectal cancer (AA vs AG+GG: OR=1.17, 95% CI=1.00–1.36, P_H=0.27) and significantly decreased risks were found for CRP 1846G/A polymorphism in breast cancer (AA vs GG: OR=0.73, 95% CI=0.56–0.95, P_H=0.93; A vs G: OR=0.88, 95% CI=0.79–0.99, P_H=0.54). For 1059G/C polymorphism, a significant association was found in colorectal cancer.

This meta-analysis showed the evidence that CRP 1059G/C and 1846G/A polymorphisms were risk factors for the development of colorectal cancer, and CRP 1846G/A polymorphism is also a protective factor for decreasing breast cancer.