In both xenograft models and co-culture systems, OSCC cells expressing EGFRvIII stimulated the expression of fibroblast activation markers—including α-smooth muscle actin (α-SMA), platelet-derived growth factor receptors (PDGFRA/PDGFRB), and collagen—thereby promoting a tumor-supportive stroma. This evidence concerns the gene ACTA1 and neoplasm.