Vascular endothelial growth factor (VEGF) (OR = 1.117, 95% CI: 1.008–1.237, P = 0.035) was positively associated with the risk of small cell lung carcinoma (Figure 4A, B) (Supplementary Table S5), but the statistical efficacy of VEGF was limited to 21%, which makes the causal hypothesis unreliable. The gene discussed is VEGFA; the disease is small cell lung carcinoma.