CEACAM5 and neoplasm: From literature several risk factors are related to lymph node metastasis such as age [5], tumor size [6, 7], carcinoembryonic antigen (CEA) level [8], consolidation/tumor ratio (CTR) [9], tumor location [10], poor differentiation [11], pleural invasion [12], lymphatic vascular invasion [13], micropapillary component [14], and tumor spread through air spaces [15].