POSTN and idiopathic pulmonary fibrosis: Although our RNA-Seq data does indicate that gene-level expression of POSTN is increased in IPF samples by a factor of 2, this increase did not reach genome-wide significance in our study (p-value = 9.5e-3), adjusted p-value = 0.1685), whereas relative down-regulation of exon 21 was highly significant (p-value = 3.01e-14, adjusted p-value = 2.06e-9).