Integrative Transcriptome-Wide Association Study With Expression Quantitative Trait Loci Colocalization Identifies a Causal VAMP8 Variant for Nasopharyngeal Carcinoma Susceptibility

Abstract

Nasopharyngeal carcinoma (NPC) is an Asia-prevalent malignancy, yet its genetic underpinnings remain incompletely understood. Here, a transcriptome-wide association study (TWAS) is conducted on NPC, leveraging gene expression prediction models based on epithelial tissues and genome-wide association study (GWAS) summary statistics from 1577 NPC cases and 6359 controls of southern Chinese descent. The TWAS identifies VAMP8 on chromosome 2p11.2 as a novel susceptibility gene for NPC. Further fine-mapping analyses pinpoint rs1058588, located within VAMP8, as a causal variant through eQTL colocalization, and GWAS analyses across multiple cohorts, achieving GWAS significance (OR = 1.18, P = 3.09 × 10⁻¹⁰). Functional assays demonstrate that VAMP8 exerts a tumorigenic role in NPC, enhancing cell proliferation, migration, and tumor growth. Mechanically, it is uncovered that rs1058588 modulates VAMP8 expression by altering its binding affinity to miR-185. Furthermore, the results show that VAMP8 interacts with DHX9 to facilitate the nuclear recruitment of p65, activating the NF-κB pathway. Collectively, the findings shed light on the genetic predisposition to NPC and underscore the critical role of the functional axis involving miR-185, VAMP8, DHX9, and the NF-κB pathway in NPC pathogenesis.