Genetic variants of NEUROD1 target genes are associated with clinical outcomes of small-cell lung cancer patients

Background: Neurogenic differentiation factor 1 (NEUROD1) is frequently overexpressed in small-cell lung cancer (SCLC). NEUROD1 plays an important role in promoting malignant behavior and survival. Methods: In this study, we evaluated the association between putative functional polymorphisms in 45 NEUROD1 target genes and chemotherapy response and survival outcomes in 261 patients with SCLC. Among the 100 single nucleotide polymorphisms (SNPs) studied, two were significantly associated with both chemotherapy response and overall survival (OS) of patients with SCLC. Results: The SNP rs3806915C>A in semaphorin 6A (SEMA6A) gene was significantly associated with better chemotherapy response and OS (p = 0.04 and p = 0.04, respectively). The SNP rs11265375C>T in nescient helix–loop helix 1 (NHLH1) gene was also associated with better chemotherapy response and OS (p = 0.04 and p = 0.02, respectively). Luciferase assay showed a significantly higher promoter activity of SEMA6A with the rs3806915 A allele than C allele in H446 lung cancer cells (p = 4 × 10⁻⁶). The promoter activity of NHLH1 showed a significantly higher with the rs11265375 T allele than C allele (p = 0.001). Conclusion: These results suggest that SEMA6A rs3806915C>A and NHLH1 rs11265375C>T polymorphisms affect the promoter activity and expression of the genes, which may affect the survival outcome of patients with SCLC.