PCNA and hemangioma: In the proliferating hemangioma there is an increase in the expression of proangiogenic factors like vascular endothelial growth factor (VEGF) as well as basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), type IV collagenase, insulin-like growth factor 2 (IGF-2), proliferating cell nuclear antigen (PCNA), the integrins α5β3 as well as α5β1, hypoxia-inducible factor (HIF)-1α, and the matrix metalloproteinases (MMP)-2 and MMP-9 (Takahashi et al., 1994; Chang et al., 1999; Ritter et al., 2002; Kleinman et al., 2007; Zhong et al., 2009).