GPT and small cell lung carcinoma: As shown in Table 2, IVW analysis results show that genetically predicted risk of small cell lung cancer has a positive causal relationship with Creatinine (β: 0.022, P: 0.002, FDR: 0.018*), Cystatin C (β: 0.026, P: 0.005*, FDR: 0.045*), and Haemoglobin HbA1c (β: 0.013, P: 0.014, FDR: 0.028*), a potential positive causal relationship with AST-ALT_ratio (β: 0.021, P: 0.022, FDR: 0.176), and a clear negative causal relationship with eGFR (β: -0.022, P: 0.003, FDR: 0.027*), and a potential negative causal relationship with Gamma Glutamyltransferase (β: -0.013, P: 0.019, FDR: 0.152).