ACTA1 and benign prostatic hyperplasia: To investigate the histological characteristics of early-progressed BPH, we performed haematoxylin and eosin (H&E), immunohistochemical (IHC) and immunofluorescence (IF) staining to observe α-SMA and collagen I expression, and Masson’s trichrome staining to identify extracellular collagen fibres in all investigated samples (Fig. 1a, b).