Heparanase, an enzyme that cleaves the heparan sulfate (HS) chains and stimulates chondrogenesis, is physiologically found only in the hypertrophic zone and perichondrium. Its wider distribution and increased activity possibly play a role in the development of osteochondromas. An in vitro study showed that a heparanase antagonist SST0001 successfully inhibited chondrogenesis. It suggests that further investigation may be profitable. The gene discussed is HPSE; the disease is Osteochondroma.