Analysis of PIK3CA and STK11 mutations, STK11 protein levels, and AMPK and AKT phosphorylation led to the identification of three major mTOR patterns in lung adenocarcinoma: (1) tumors with minimal or basal mTOR pathway activation, (2) tumors showing higher mTOR activity accompanied by either STK11-inactivating mutation or combined low STK11 expression and low AMPK activation and (3) tumors showing high mTOR activity accompanied by either phosphorylated AKT activation, PIK3CA mutation, or both. This evidence concerns the gene STK11 and lung adenocarcinoma.