CD74 and lung adenocarcinoma: CD74 functions in multiple biological processes and disease types, including lung adenocarcinoma (31), kidney disease (32), spondyloarthritis (33), colitis (34), etc. Collagen type I alpha 1 chain (COL1A1) and collagen type V alpha 1 chain (COL5A1) are the members of collagen family (35), mainly involved in various courses of tumor development, such as hepatocellular carcinogenesis and metastasis (36), immune infiltration in mesothelioma (37), metastasis of lung adenocarcinoma (38), tumor progression in ovarian cancer (39).