Investigation of differences in p53 gene polymorphisms between schizophrenia and lung cancer patients in the Turkish population

The reduced incidence of cancer observed in schizophrenia patients may be related todifferences in genetic background. It has been suggested that genetic predisposition towardsschizophrenia is associated with reduced vulnerability to lung cancer, and p53 gene is one ofthe candidate genes. In our study, we aimed to investigate polymorphisms in the BstUI inexon 4 and MspI in intron 6 restriction sites of the p53 gene in Turkish schizophrenia, lungcancer patients and controls.Allele and genotype incidence of these polymorphisms with their haplotypecombinations were studied in 100 Turkish lung cancer and schizophrenia patients and 100controls without malignant and shizophrenia diseases. The genotype characteristics weredetermined by PCR-based RFLP method using DNA extracted from peripheral blood.For the BstUI and MspI polymorphism, there were found significant differences in thegenotype and allele frequencies between schizophrenia and lung cancer patients with controlgroups (p<0.01). The analysis based on haplotype frequencies showed the presence of BstUI-MspI 2-1 haplotype in cancer patients (12%) in contrast to the absence of this haplotype inschizophrenia and controls. Only in lung cancer patients we found both significant decrease ofA1 allele of the p53 codon 72 (OR 0.23, 95% CI 0.9-0.58) and A1/A1 homozygous genotype(P<0.0001, OR 0.19).The results of this study suggest a protective effect of A1 allele against lung cancerand the p53 MspI polymorphism may modify the susceptibility to lung cancer as a singlefactor rather than in combination with BstUI polymorphism.Keywords: Cancer risk, Single nucleotide polymorphism, Schizophrenia, Lungcancer, p53 gene.