Single-center, prospective, observational cohort study. 120 patients with advanced (stage III unresectable or IV) solid tumors candidates for first-line immunotherapy and 30 healthy controls are enrolled (total N=150). Patients provide saliva, stool and tongue-scraping samples plus archival FFPE tumor tissue at baseline (V0) and at 6 (V1) and 12 (V2) months; controls provide saliva and stool at V0 only. Microbiomes are profiled by PacBio HiFi shotgun metagenomics and full-length 16S; tumor transcriptome by RNA-Seq; and saliva/stool metabolome by GC-MS in a subcohort (n=60). Tumor response is assessed by RECIST 1.1. Microbial, transcriptomic and metabolomic features are integrated with clinical outcomes (objective response, PFS, OS) using multivariable and machine-learning models.
