HLA-C and neoplasm: Through T cell receptor (TCR) clonal lineage tracing, fate mapping and peptide-major histocompatability complex (MHC) tetramer staining, we identify tumour-associated SFB-specific T helper 1 (T<sub>H</sub>1)-like cells derived from the homeostatic T<sub>H</sub>17 cells induced by SFB colonization in the SILP.