Prognostic value of an APOBEC3 deletion polymorphism for glioma patients in Taiwan

OBJECTIVE The molecular pathogenesis of malignant gliomas, characterized by diverse tumor histology with differential prognosis, remains largely unelucidated. An APOBEC3 deletion polymorphism, with a deletion in APOBEC3B, has been correlated to risk and prognosis in several cancers, but its role in glioma is unclear. The authors aimed to examine the clinical relevance of the APOBEC3 deletion polymorphism to glioma risk and survival in a glioma patient cohort in Taiwan. METHODS The authors detected deletion genotypes in 403 glioma patients and 1365 healthy individuals in Taiwan and correlated the genotypes with glioma risk, clinicopathological factors, patient survival, and patient sex. APOBEC3 gene family expression was measured and correlated to the germline deletion. A nomogram model was constructed to predict patient survival in glioma. RESULTS The proportion of APOBEC3B(-/-) and APOBEC3B(+/-) genotypes was higher in glioblastoma (GBM) patients than healthy individuals and correlated with higher GBM risk in males. A higher percentage of cases with APOBEC3B(-) was observed in male than female glioma patients. The presence of APOBEC3B(-/-) was correlated with better overall survival (OS) in male astrocytic glioma patients. No significant correlation of the genotypes to glioma risk and survival was observed in the female patient cohort. Lower APOBEC3B expression was observed in astrocytic glioma patients with APOBEC3B(-/-) and was positively correlated with better OS. A 5-factor nomogram model was constructed based on male patients with astrocytic gliomas in the study cohort and worked efficiently for predicting patient OS. CONCLUSIONS The germline APOBEC3 deletion was associated with increased GBM risk and better OS in astrocytic glioma patients in the Taiwan male population. The APOBEC3B deletion homozygote was a potential independent prognostic factor predicting better survival in male astrocytic glioma patients.