Single Nucleotide Polymorphisms in IL-10, IL-12p40, and IL-13 Genes and Susceptibility to Glioma

Glioma is one of the most aggressive and most common tumors of the central nervous system (CNS) in humans. The exact causes of glioma are not well known, but evidence suggests the involvement of genetic factors in addition to environmental risk factors. The present study aimed to determine whether polymorphisms in IL-10-1082A/G, IL-12p40 1188C/A, and IL-13+2044G/A (rs20541) are associated with the incidence of glioma in Iraqi patients. Ninety-six patients with different grades of glioma and 40 apparently healthy individuals were recruited. A blood sample and genomic DNA were collected from all subjects. The amplification refractory mutation system and sequence-specific primer polymerase chain reaction (PCR) were used for genotyping of IL-10-1082A/G and IL-12p40 1188C/A, respectively; whereas, the IL-13+2044G/A was detected by DNA sequencing after amplification of the genes by PCR. All SNPs were within Hardy-Weinberg equilibrium and each appeared in three genotypes in patients and controls. In IL-10-1082A/G, these genotypes frequencies were AA (75%), AG (22.93%) and GG (2.07%) in patients as compared to similar frequencies (62.5%), (27.5%) and (10%) respectively, in controls. The variant IL-12p40 1188C/A genotype was AA (72.92%), AC (23.96%), and CC (3.13%%) in patients as compared to 65%, 30%, and 5%, respectively, in controls. The frequencies of IL-13+2044G/A genotypes (GG, GA, and AA) were 89.58%, 9.37%, and 1.04% among patients versus 47.5%, 32.5% and 20%, respectively, among controls. These results suggest a protective role of mutant alleles G and A in IL-10-1082A/G and IL-13+2044G/A against gliomas. Further studies with more rigorous parameter designs will be needed to confirm the current findings.