The proliferative markers Hgf, IL6st, Mki67, Hnf4a were increased in the PCS group compared to the S group (P = 0.034; P = 0.023; P = 0.015; and P = 0.003), whereas only Hnf4a was significantly increased in the PVL group (P = 0.044). This evidence concerns the gene MKI67 and periventricular leukomalacia.