Serum C-reactive protein and risk of lung cancer: a case-control study

Recent advances in lung cancer biology presuppose their inflammatory origin. Thus, CRP is regarded to play a key role in the development of lung cancer. Nevertheless, this interesting hypothesis and the role of inflammation in tumor biology remain complex and incompletely sure. Meanwhile, the association between CRP and risk of lung cancer was not stable in many published results. This study was conducted to evaluate the association between serum CRP and SNPs in the aspect of lung cancer risks, in order to assess its possible diagnostic and prognostic importance. We conducted a case-control study of 96 patients newly diagnosed of lung cancer and 124 controls in this research. Controls were individuals matched to lung cancer cases on age, gender and tobacco use. In order to increase the statistical power, never smokers were matched to patients by using a 3: 1 ratio, whereas former and current smokers were matched equal to the patients. CRP concentrations were measured using a chemiluminescent immunoassay, and SNPs were assessed at five loci within the CRP gene (rs1417938, rs1800947, rs1205, rs2808630 and rs3093077) as part of a Golden Gate assay. Logistic regression was used to calculate OR and 95 % CI for lung cancer. CRP concentrations tended to be in positive association with lung cancer risk in our research (Q4 vs Q1: OR = 2.11, 95 % CI, 1.66-2.91, p trend < 0.01). Although CRP SNPs were related to CRP levels, they were not associated with lung cancer risk. In combined analyses, we observed a significant interaction (p(interaction) = 0.02) that positive associations were suggestive in younger (Q4 vs Q1: OR = 1.65, 95 % CI, 1.02-2.67, p trend = 0.18) and older individuals (Q4 vs Q1: OR = 2.66, 95 % CI, 1.45-3.98 p trend = 0.42). The risks of lung cancer were higher with elevated CRP levels among former smokers and current smokers. High levels of CRP were associated with increasing lung cancer risk, suggesting that CRP could be used as surrogate biomarker of angiogenesis and prognosis in lung cancer.