Two recent genome-wide association studies reported that single nucleotide polymorphisms (SNPs) in (or near) TERT (5p15), CCDC26 (8q24), CDKN2A/B (9p21), PHLDB1 (11q23), and RTEL1 (20q13) are associated with infiltrating glioma. From these reports it was not clear if the SNP associations predispose to glioma in general or whether they are specific to certain glioma grades or morphologic subtypes. To identify hypothesized associations between susceptibility loci and tumor subtype, we genotyped two case/control groups composed of the spectrum of infiltrating glioma subtypes, and stratified the analyses by type. We report that specific germline polymorphisms are associated with different glioma subtypes. CCDC26 (8q24) region polymorphisms are strongly associated with oligodendroglial tumor risk (rs4295627, OR=2.05, p=8.3*10−11), but not glioblastoma risk. The opposite is true of RTEL (20q13) region polymorphisms which are significantly associated with glioblastoma (rs2297440, OR = 0.56, p= 4.6*10−10) but not oligodendroglial tumor. The SNPs in or near CCDC26 (8q24) are associated with oligodendroglial tumors regardless of combined 1p and 19q deletion status; however, the association is greatest for those with combined deletion (rs4295627, OR=2.77, p=2.6*10-9). These observations generate hypotheses concerning the possible mechanisms by which specific SNPs (or alterations in linkage disequilibrium with such SNPs) are associated with glioma development.
Keywords: Glioma, Genetic Association, 1p/19q deletion