Conversely, PC(32:3), (34:4), (34:3), and PC with alkylether (36:4) or plasmalogen (36:3) at sn-1 position were decreased in marginal areas (Fig. 4c), indicating that some of the altered PC species represent potentially important metabolic features in HNSCC cells with activated TGF-β signalling and are surrogate lipid markers for activation of TGF-β signalling in HNSCC. Here, TGFB1 is linked to head and neck squamous cell carcinoma.