The secreted growth factor pleiotrophin (PTN), also called heparin binding growth-associated molecule (HB-GAM), heparin affin regulatory peptide (HARP), heparin-binding growth factor 8, heparin-binding neurotrophic factor (HBNF), or osteoblast-specific protein-1 (OSF-1) is a 15.3-kDa developmentally regulated cytokine, which shows very limited expression in normal adult tissues, but is markedly upregulated in various primary human tumors and tumor cell lines [55,57]. The gene discussed is PTN; the disease is neoplasm.