FN1 and neoplasm: For example, myCAFs promote the invasion and metastasis of tumor cells by secreting collagen and fibronectin and other extracellular matrix proteins; iCAFs recruit immunosuppressive cells such as regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) by secreting IL-6, IL-8 and other inflammatory factors, inhibiting the anti-tumor activity of immune cells (14–16).