There were causal associations between S100A14 (Wald ratio, OR = 2.11, 95% CI, 1.50–2.96, FDR = 0.0144) and S100A16 (IVW, OR = 0.70, 95% CI, 0.60–0.82, FDR = 0.0144) and HER-positive breast tumors, between PDE5A (IVW, OR = 1.53, 95% CI, 1.25–1.87, FDR = 0.0304) and colorectal cancer, and between MIA (IVW, OR = 0.82, 95% CI, 0.76–0.88, FDR = 0.0005) and non-small cell lung cancer. The gene discussed is PDE5A; the disease is breast neoplasm.