This could provide a platform for a sustained release of growth factors identified in HPS, such as vascular endothelial growth factor (VEGF) [13,15,16,17,18,19], platelet-derived growth factor BB (PDGF-BB) [17,20], basic fibroblast growth factor (bFGF) [17,20], epidermal growth factor (EGF) [18], transforming growth factor-beta1 (TGF-beta1) [17], and insulin-like growth factor-1 (IGF-1) [20]. Here, IGF1 is linked to Hermansky-Pudlak syndrome.