ERBB2 and neoplasm: In the case of CAFs, our interest in analysing the molecular components of the secretome went beyond the dynamic description of the usual markers (αSMA, FAP, S100A4, CV1, PDGFRβ, IL6, etc.), and we aimed to characterize the pathophysiological role of CAFs in the context of their interaction with tumour cells in the TME, analysing possible activations of EGFR, TGF-β, JAK/STAT, Wnt/β-catenin and Hippo signalling pathways in relation to anti-HER2 resistance.