A rare KLHDC4 variant Glu510Lys is associated with genetic susceptibility and promotes tumor metastasis in nasopharyngeal carcinoma

Various genetic association studies have identified numerous single nucleotide polymorphisms (SNPs) associated with nasopharyngeal carcinoma (NPC) risk. However, these studies have predominantly focused on common variants, leaving the contribution of rare variants to the "missing heritability" largely unexplored. Here, we integrate genotyping data from 3925 NPC cases and 15,048 healthy controls to identify a rare SNP, rs141121474, resulting in a Glu510Lys mutation in KLHDC4 gene linked to increased NPC risk. Subsequent analyses reveal that KLHDC4 is highly expressed in NPC and correlates with poorer prognosis. Functional characterizations demonstrate that KLHDC4 acts as an oncogene in NPC cells, enhancing their migratory and metastatic capabilities, with these effects being further augmented by the Glu510Lys mutation. Mechanistically, the Glu510Lys mutant exhibits increased interaction with Vimentin compared to the wild-type KLHDC4 (KLHDC4-WT), leading to elevated Vimentin protein stability and modulation of the epithelial-mesenchymal transition process, thereby promoting tumor metastasis. Moreover, Vimentin knockdown significantly mitigates the oncogenic effects induced by overexpression of both KLHDC4-WT and the Glu510Lys variant. Collectively, our findings highlight the critical role of the rare KLHDC4 variant rs141121474 in NPC progression and propose its potential as a diagnostic and therapeutic target for NPC patients.