Region-based analyses of existing genome-wide association studies identifies novel potential genetic susceptibility regions for glioma.
PURPOSE Glioma is a rare and debilitating brain cancer with one of the lowest cancer survival rates. Genome-wide association studies have identified 34 genetic susceptibility regions. We sought to discover novel susceptibility regions using approaches which test groups of contiguous genetic markers simultaneously. PATIENTS AND METHODS We analyzed data from three independent glioma studies of European ancestry, GliomaScan (1,316 cases/1,293 controls), AGOG (560 cases/2,237 controls), and GICC (4,000 cases/2,411 controls), using the machine-learning algorithm DEPTH and a region-based regression method based on the generalized Berk-Jones (GBJ) statistic, to assess the association of glioma with genomic regions by glioma type and sex. Summary statistics from the UCSF/Mayo Clinic study were used for independent validation. We conducted a meta-analysis using GliomaScan, AGOG, GICC and UCSF/Mayo. RESULTS We identified 11 novel candidate genomic regions for glioma risk common to multiple studies. Two of the 11 regions, 16p13.3 containing RBFOX1 and 1p36.21 containing PRDM2, were significantly associated with female and male glioma risk respectively, based on results of the meta-analysis. Both regions have been previously linked to glioma tumor progression. Three of the 11 regions contain neurotransmitter receptor genes (7q31.33 GRM8, 5q35.2 DRD1, 15q13.3 CHRNA7). CONCLUSIONS Our region-based approach identified 11 genomic regions that suggest association with glioma risk of which two regions, 16p13.3 and 1p36.21, warrant further investigation as genetic susceptibility regions for female and male risk respectively. Our analyses suggest that genetic susceptibility to glioma may differ by sex and highlights the possibility that synapse-related genes play a role in glioma susceptibility.