CEACAM5 and lung cancer: Commonly studied markers include carcinoembryonic antigen (CEA), C-reactive protein (CRP), lactate dehydrogenase (LDH), neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), and the advanced lung cancer inflammation index (ALI), all of which have been widely examined as prognostic or risk assessment indicators for lung cancer [3,4,5,6,7].