SFTPB and neoplasm: Based on their immunohistochemistry (IHC) results, early-stage lung adenocarcinoma (LUAD) patients who showed no difference in pro-SFTPB expression in the tumor and its adjacent tissue were placed in the pro-SFTPB normal expression group, and patients in whom pro-SFTPB expression was lower in the tumor than in the adjacent tissue were placed in the pro-SFTPB low expression group (Fig. 1a).