In addition, the associations between the level of carcinoembryonic antigen (CEA) and frequency of Th22 cells in patients with AC and between the level of cytokeratin-19-fragment (CYFRA21-1) and frequency of Th22 cells in patients with squamous cell carcinoma (SCC) were, respectively, analyzed. Here, CEACAM5 is linked to squamous cell carcinoma.