TP53 and small cell lung carcinoma: Based on the functional prediction results of Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt2) (Fig. 3E), according to the annotation results of the Statistical Analysis of Metagenomic Profiles (STAMP) differential analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) database function with P < 0.05, a total of seven level 3 pathways were identified, which were related to Parkinson’s disease (PD), viral myocarditis, toxoplasmosis, small cell lung cancer, p53 signaling pathway, influenza A, and colorectal cancer.