As illustrated in Figure 1, we found that p53 and microRNA-34a are relatively low in human lung fibroblasts from uninjured lungs and that levels are even reduced in fLfs from the lungs of patients with IPF or with bleomycin-induced pulmonary fibrosis due to loss of baseline caveolin-1-mediated feedback induction of expression [30,43,44]. This evidence concerns the gene CAV1 and idiopathic pulmonary fibrosis.