Against this background, it appears obvious that the heterogenous cellular morphology of HNSCC cells, as seen in histopathological sections, could be induced by a more or less active TGF-β signaling pathway due to, e.g., TGF-β signaling associated cytokines derived from the tumor cell itself or from other cells in the tumor microenvironment (TME) [21]. This evidence concerns the gene TGFB1 and head and neck squamous cell carcinoma.