To demonstrate the correlation between the leptin levels and routine clinical tumor markers in lung adenocarcinoma in response to cisplatin/pemetrexed chemotherapy, Spearman’s correlation was performed between the serum leptin levels and the routine tumor biomarkers, including CEA, CA125, CA15-3, CA19-9, CA72-4, CYFRA21-1, NSE and SCC. Here, CEACAM5 is linked to lung adenocarcinoma.