Activation in Malignant Epithelial Ovarian Tumors Elevated Hyaluronan Concentration without Hyaluronidase

The concentration and histological distribution of hyaluronan, a tumor promoting extracellular matrix polysaccharide, and the activity of hyaluronidase, a potential source of angiogenic hyaluronan oligosaccharides, were analyzed in malignant epithelial (n 24), borderline (n 8), benign epithelial (n 20), functional cyst (n 21), and normal (n 5) tissue samples of human ovary. Hyaluronan concentration increased specifically in cancers (P 0.001), particularly in grade 3 tumors (>49-fold) and in metastases (>89-fold). Hyaluronan staining in the tissues correlated with hyaluronan concentration (P 0.002). Hyaluronidase activity slightly decreased from semimalignant through low grade to high grade tumors (P 0.041). Therefore, hyaluronan accumulation, but not hyaluronidase activation, is associated with the aggressiveness of ovarian epithelial cancer.