In early lung cancer patients' analysis, HSP70 was found to have more diagnosis valuable (AUC: 83.8%, SN: 71.2%, SP: 84.0%) than CEA (AUC: 73.7%, SN: 73.2%, SP: 69.1%) and CA 19-9 (AUC: 61.5%; SN: 69.4%; SP: 53.4%). The gene discussed is CEACAM5; the disease is lung cancer.