PECAM1 and cavernous hemangioma: Double immunostaining for endothelial (ERG1, COLLAGEN IV, PECAM1) and EndMT markers (i.e., FSP1, pSMAD3, ID1, FN1, SCA1, αSMA, KLF4) in the chronic model showed that at early stage (P8) small lesions are composed mostly by endothelial cells that expressed higher levels of EndMT markers if compared to cells of surrounding normal vessels, while at later stages (P14), in larger cavernomas only a subset of endothelial cells underwent EndMT (Fig. 4).