ANTIBODIES TO BENZO[A]PYRENE, ESTRADIOL AND PROGESTERONE AND GENE POLYMORPHISMS OF CYTOKINES: ASSOCIATIONS WITH LUNG CANCER IN MEN

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Previous studies have revealed associations of antibodies, specific to chemical carcinogens and steroid hormones with lung cancer in men. However, the mechanisms of their formation and action were remained unclear. In particular, the relationships between antibodies and gene polymorphisms of cytokines were un- known. The purpose of this study was to identify possible associations between occurrence of A class antibodies, specific to benzo[a]pyrene, estradiol and progesterone (IgA-Bp, IgA-Es and IgA-Pg), and frequency of genetic polymorphisms of IL1RN VNTR, IL1В (rs1143634, rs16944), IL4 VNTR, IL6 (rs1800795), IL10 (rs1800896), TNFA (rs1800629, rs361525) genes in healthy male smokers and lung cancer patients. We have examined 381 men with non-small cell lung cancer and 158 apparently healthy donors without respiratory diseases. A non-competitive solid phase immunoassay of antibodies was performed. Analysis of polymorphic loci of IL1RN (VNTR, intron 2), IL4 (VNTR, intron 3) was performed by means of conventional PCR; IL1В (rs1143634, rs16944), IL6 (rs1800795) SNPs were detected by RFLP, and IL10 (rs1800896), TNFA (rs1800629, rs361525) genotyping was carried out with TaqMan Real-time PCR. Results of the study have shown that the proportion of cases with high level of IgA-Pg and low levels of both IgA-Bp and IgA-Es among the lung cancer patients was lower than in healthy men (OR = 0.31, p < 0.0001). Vice versa, the ratio of cases with high levels of both IgA-Bp and IgA-Es and low levels of IgA-Pg was higher in lung cancer patients (OR = 3.6, p < 0.0001). No relationships were revealed between the levels of antibodies, and rates of genetic polymorphisms for the studied cytokines in both groups of men. At the same time, the detected associations of IgA-Bp, IgA-Es and IgA-Pg with lung cancer proved to be significant only in carriers of certain cytokine genotypes, e.g., in AG IL10 heterozygotes (OR = 5.1, p < 0.0001). In conclusion, these results provide indirect evidence that IgA-Bp and IgA-Es could stimulate initiation and promotion of lung carcinogenesis. On the contrary, IgA-Pg could inhibit the promotion of carcinogenesis. Immunoassay of these antibodies combined with molecular biology studies of IL10 gene variants are recommended for the lung cancer risk assessment.