To strengthen the evidence that decreased ING4 expression may contribute to the progression of fibrosis we sought to correlate ING4 semi-quantitative immunohistochemistry expression levels with pulmonary function parameters including forced vital capacity (FVC), total lung capacity (TLC) and diffuse lung capacity as expressed by KCO (carbon monoxide transfer coefficient), in IPF patients. The gene discussed is ING4; the disease is idiopathic pulmonary fibrosis.