BACKGROUND: Cancer-associated fibroblasts (CAFs) are molecularly heterogeneous mesenchymal cells that interact with malignant cells and immune cells and confer both anti- and pro-tumorigenic functions. Prior in situ profiling studies of human CAFs have largely relied on scoring single markers, thus presenting a very limited view of their molecular complexity. Our objective was to study the complex spatial tumor microenvironment of non-small cell lung cancer (NSCLC) with multiple CAF biomarkers, identify novel CAF subsets and explore their associations with patient outcome. METHODS: Multiplex fluorescence immunohistochemistry (mfIHC) was employed to spatially profile the CAF landscape in two population-based NSCLC cohorts (n_=_636) using antibodies against four fibroblast markers: Platelet-derived growth factor receptor-alpha (PDGFRA) and -beta (PDGFRB), fibroblast activation protein (FAP), and alpha-smooth muscle actin (_SMA). The CAF subsets were analyzed for their correlations with mutations, immune characteristics, clinical variables as well as overall survival (OS). RESULTS: Two CAF subsets, CAF7 (PDGFRA-/PDGFRB+/FAP+/_SMA+) and CAF13 (PDGFRA+/PDGFRB+/FAP-/_SMA+), showed significant but opposite associations with tumor histology, driver mutations (TP53 and EGFR), immune features (PD-L1 and CD163), and prognosis. In patients with early-stage tumors (pTNM IA-IB), CAF7 and CAF13 acted as independent prognostic factors. CONCLUSIONS: Multi-marker-defined CAF subsets were identified through high-content spatial profiling. The robust associations of CAFs with driver mutations, immune features, and outcome suggest CAFs as essential factors in NSCLC progression and warrant further studies to explore their potential as biomarkers or therapeutic targets. This study also highlights mfIHC-based CAF profiling as a powerful tool for the discovery of clinically relevant CAF subsets.
Fibroblast subsets in non-small cell lung cancer: associations with survival, mutations, and immune features
(1) Pellinen T (2) Paavolainen L (3) Martn-Bernab A (4) Papatella Araujo R (5) Strell C (6) Mezheyeuski A (7) Backman M (8) La Fleur L (9) Brck O (10) Sjlund J (11) Holmberg E (12) Vlimki K (13) Brunnstrm H (14) Botling J (15) Moreno-Ruiz P (16) Kallioniemi O (17) Micke P (18) stman A
