ACTA1 and polyp: In contrast, an increase of TGF-β activated α-SMA expressing myofibroblasts was noted in the turbinate part of middle turbinate CRSwNP, paralleled by an increased deposition of collagen, representing a defence mechanism against inflammation and edema formation in the polyp part, particularly as there was a lack of collagen and deposition of fibronectin in the early stage polyp.