Primary lung cancer and TNF-alpha gene polymorphisms: a case-control study in a Croatian population

Tumor necrosis factor-alpha (TNF-alpha) is a multifunctional cytokine involved in the pathogenesis of various inflammatory and malignant diseases. Previous studies investigating the role of the TNF-alpha gene polymorphisms in lung cancer have generated contradictory results. The present study investigated whether the TNF-alpha-308 and TNF-alpha-238 polymorphisms are associated with risk and/or severity of disease in Croatian lung cancer patients. This is the first study in a Caucasian population to analyze the influence of these two polymorphisms on multiple types of lung cancer.

In a case-control study, lung cancer patients (n=230) and appropriate age- and sex-matched controls (n=230) were genotyped by the polymerase chain reaction/restriction fragment length polymorphism method. Allele and genotype frequencies were estimated by gene counting. The chi-squared test was used to compare the observed numbers of different TNF-alpha genotypes for the population with those predicted by Hardy-Weinberg equilibrium. Differences in genotype and allele distributions in the patient and control groups were analyzed for statistical significance using the chi-squared test or Fisher's exact test as appropriate.

There were no significant differences in the genotype and allele frequencies for the TNF-alpha-308 and TNF-alpha-238 polymorphisms between lung cancer patients and controls. Furthermore, no association between the genotypes and different stages of lung cancer was detected.

This study indicates that the TNF-alpha-308 and TNF-alpha-238 polymorphisms do not influence susceptibility to or severity of lung cancer in a Croatian population.