Total protein demonstrated a potential negative causal relationship with lung squamous cell carcinoma (β: -0.402, P: 0.009, FDR: 0.072), while AST/ALT revealed a potential positive causal relationship with lung adenocarcinoma (β: 0.293, P: 0.009, FDR: 0.072). This evidence concerns the gene GPT and squamous cell lung carcinoma.