In contrast, Arginase I is also constitutively expressed in bronchial epithelial cells, endothelial cells and (myo-) fibroblasts31.In line with our in vitro observations, when we analysed the M2 marker gene expression, we detected upregulation of Stabilin-1, Retnla and a trend for Arginase I in BLM-treated PTENMyKO mice compared to littermate wild-type controls, while Chi3l3 was not changed (Fig. 3g). This evidence concerns the gene STAB1 and Bloom syndrome.