These results were further supported by immunoblots for the proliferation markers phospho (p)-histone H3 (Fig 2C) and cyclin D1 (Fig 2D), indicating equal expression of both proteins in pirfenidone- and vehicle-treated IPF-fibroblasts, but significant suppressed levels in LBH589-treated cells. Here, CCND1 is linked to idiopathic pulmonary fibrosis.