In support of these conclusions we found that; i) in myeloma patients, tumor cells that survive sequential rounds of chemotherapy express high levels of heparanase, ii) high heparanase promotes chemoresistance via ERK signaling, iii) the heparanase inhibitor Roneparstat sensitizes myeloma cells to chemotherapy, and iv) Roneparstat has the potential to prevent regrowth of tumors after chemotherapy. The gene discussed is HPSE; the disease is plasma cell myeloma.