Association study of a functional copy number variation in the WWOX gene with risk of gliomas among Chinese people

Gliomas represents more than 80% of all malignant brain tumors. However, the etiology still remains largely unknown. Human WW domain-containing oxidoreductase (WWOX), which is located at 16q23.1-16q23.2, the common fragile site 16D (FRA16D), an area with a high frequency of gene deletions or chromosomal alterations, has been identified as a tumor suppressor gene in multiple cancers. In current study, we analyzed the WWOX deletion (CNV-67048) in a large, case-control study of 3,622 adult Chinese people (including 1,798 glioma cases and 1,824 healthy controls). All participants were genotyped using real-time qualitative PCR (qPCR), and its biological effect was validated with mRNA expression assays. The deletion was significantly associated with glioma risk, with ORs (95% CIs) of 1.21 (1.05-1.41) associated with 1 copy deletion and 1.94 (1.37-2.75) associated with 2 copy deletion as compared with subjects with no deletion (p for trend = 8.05 x 10(-6)). Additional adjustments and stratified analyses did not change the results materially. The mRNA levels of WWOX in glioma tissues were significantly lower than that of their border tissues (p = 0.007), especially in the loss genotyped subjects. Our data suggest that the loss genotypes of CNV-67048 in WWOX gene predispose their carriers to gliomas, and WWOX gene deletion may be a new biomarker for predicting risk of gliomas.