As angiogenesis[15,18,19] and apoptosis[20,21] represent two of the major pathogenetic hallmarks of pulmonary fibrosis and since HIF-1a, the major transcription factor of hypoxia-related genes involved in angiogenesis and apoptosis, has been recently implicated in the pathogenesis of fibrotic lung disease we sought to investigate the expression of its inhibitor, ING4, both in mRNA and protein level using qRT-PCR and immunohistochemistry analysis, respectively, in a well characterized model of pulmonary fibrosis. This evidence concerns the gene HIF1A and pulmonary fibrosis.