Heparanase levels are elevated in the plasma of pediatric cancer patients and correlate with response to anticancer treatment.

Heparanase is an endoglycosidase that specifically cleaves heparan sulfate (HS) side chains of heparan sulfate proteoglycans, the major proteoglycan in the extracellular matrix (ECM) and cell surfaces. Heparanase upregulation was documented in an increasing number of primary human tumors, correlating with reduced postoperative survival rate and enhanced tumor angiogenesis. The purpose of the current study was to determine heparanase levels in blood samples collected from pediatric cancer patients using an ELISA method. Heparanase levels were elevated four-fold in the plasma of cancer patients compared with healthy controls (664 +/- 143 vs 163 +/- 18 pg/ml, respectively). Evaluating plasma samples following anticancer therapy revealed reduced heparanase levels (664 +/- 143 vs 429 +/- 82 pg/ml), differences that are statistically highly significant (P = .0048). Of the 55 patients with complete remission (CR) or very good partial remission (VGPR) at restaging, 41 (74.5%) had lower heparanase amounts, whereas 14 patients (25.5%) had similar or higher amounts of plasma heparanase. All nine patients with stable or advancing disease had similar or elevated levels of heparanase on restaging. The results show that heparanase levels are elevated in the plasma of pediatric cancer patients and closely correlate with treatment responsiveness, indicating that heparanase levels can be used to diagnose and monitor patient's response to anticancer treatment.