Serum folate concentration and the incidence of lung cancer

Background

Lung cancer is a leading cause of cancer-related mortality globally. Folate helps to maintain DNA integrity and to regulate gene expression. Serum folate levels may affect the risk of several cancers, including lung cancer. In this study we evaluated the association between serum folate concentration and variations in genes involved in folate metabolism with lung cancer incidence in Poland.

Methods

The study included 366 lung cancer patients and 366 control subjects. We measured serum folate concentration and genotyped six variants in MTHFR, MTR and MTRR genes. The odds ratios of being diagnosed with lung cancer were calculated using conditional univariable and multivariable logistic regression with respect to folate level and genotypes.

Results

The mean serum folate level was lower in lung cancer cases than in control group (20.07 nmol/l vs. 22.52 nmol/l, p = 0.002). The odds ratio for lung cancer declined with increasing serum content of the folate. The folate concentration of >25.71 nmol/l (IVth quartile) in comparison to <15.92 nmol/l (Ist quartile) was associated with an odds ratio of 0.61 (95%CI 0.40–0.95, p = 0.03). The analysis of variations in MTHFR, MTR and MTRR genes did not reveal any significant difference between lung cancer cases and controls in univariable and multivariable analyses.

Conclusion

In this case-control study, lower serum folate concentrations were associated with a higher risk of lung cancer diagnosis. Although previous findings have been somewhat mixed, our results add to the evidence that circulating folate levels may be an indicator of lung cancer risk.

Serum 25(OH)D concentration, common variants of the VDR gene and lung cancer occurrence

The first aim of our study was to examine the association between common variants in VDR [rs2228570 (FokI), rs1544410 (BsmI), rs7975232 (ApaI), rs731236 (TaqI) and rs11568820 (Cdx2)] and lung cancer risk in the Polish population. Genotyping and statistical analysis which included Chi-square test with Yates correction and haplotype frequency analysis were performed on a series of 840 consecutively collected lung cancer patients and 920 healthy controls. The second aim was to evaluate the link between serum 25(OH)D concentration and the number of lung cancers in a subgroup of 200 patients. A separate control group that consisted of 400 matched (by age, sex, smoking habits and the season of blood collection) healthy individuals was used to avoid posterior adjustment on the matched variables. Statistical analysis with the use of Chi-square test with Yates was performed. We found no statistically significant difference in the distribution of the allels of studied VDR variants among cases and controls. A statistically significant over-representation of VDR haplotypes: rs731236_A + rs1544410_T [odds ratio (OR) = 2.43, 95% confidence interval (CI) = 1.11-5.32, p < 0.001], rs731236_G + rs1544410_T (OR = 1.54, 95% CI = 1.31-1.81, p < 0.001) and rs731236_G + rs1544410_C (OR = 0.04, 95% CI = 0.03-0.07, p < 0.001) was detected. We found a tendency toward an increased number of lung cancers among individuals with low serum levels of 25(OH)D. To answer the question, whether VDR can be regarded as lung cancer susceptibility gene and low 25(OH)D serum levels is associated with lung cancer occurrences, additional, multicenter study needs to be performed.