Notably, in breast cancer patients, AGR2 overexpression could predict poor outcomes (OS: HR 3.02, 95% CI 1.03–8.81; TTP: HR 1.93, 95% CI 1.17–3.20), which was not observed in lung cancer, ovarian cancer, and colorectal cancer (OS for lung cancer: HR 1.41, 95% CI 0.90–2.23; OS for colorectal cancer: HR 0.80, 95% CI 0.41–1.53; TTP for ovarian cancer: HR 1.09, 95% CI 0.09–13.84). This evidence concerns the gene AGR2 and lung cancer.