S100A4 and Bloom syndrome: To validate the expression of YAP1 in AT2 cells, we performed dual immunofluorescence staining on frozen lung sections, which revealed decreased colocalization of YAP1 and Sftpc in BLM-treated mice (Fig. 1c) but increased expression of YAP1 in S100A4-labeled lung fibroblasts (Fig. 1d).