We have recently demonstrated that VILI in the immature lung induces a rapid increase in distal lung cell proliferation [19] which is consistent with the fibroblast proliferation seen in infants with BPD [1] We have also identified a number of early response genes (CTGF, EGR1 and CYR61) that regulate cell proliferation and are thought to play a role in normal lung development [22]. This evidence concerns the gene CCN2 and bronchopulmonary dysplasia.