We graded the coded lung samples with the standard clinical system (0–3; none, mild, moderate and severe), and found that after Bleomycin treatment, C/EBPβwt mice had moderate to severe lung fibrosis (mean score 2.8+/−0.4; n: 10) compared to controls , while C/EBPβ-Ala217 mice of the same genetic background had mild or moderate lung fibrosis (mean score: 1.5+/−0.5; n: 10; P<0.001; Wilcoxon U Test) (Figure 1A). This evidence concerns the gene CEBPB and pulmonary fibrosis.