Background: YKL-40, also called human cartilage glycoprotein-39 (HC gp-39) and chitotriosidase are homologs of family 18 glycosyl hydrolases secreted by human macrophages. Although high levels of YKL-40 and chitotriosidase are associated with several diseases, the physiological functions of these enzymes are still unclear. YKL-40, a growth factor for connective tissue cells, a migration factor for endothelial and vascular smooth muscle cells, is expressed by several types of solid human carcinoma, including prostate carcinoma.
Purpose: The purpose of this study was to compare serum YKL-40 levels and chitotriosidase activity both in benign prostatic hyperplasia and primary prostate cancer.
Methods: YKL-40 and chitotriosidase were determined in serum samples from 93 patients with primary prostate cancer and 61 patients with benign prostatic hyperplasia. Serum YKL-40 levels were measured by ELISA and chitotriosidase activity was determined by fluorometer. PSA levels were also measured by using an automated system.
Results: Serum YKL-40 levels were significantly higher (P < 0.001) in patients with prostate cancer compared with control group whereas there was no significant difference between BPH and control group. Serum chitotriosidase activities were significantly higher in carcinoma patients with high Gleason score than the control group (P < 0.001). No significant difference was observed in BPH patients (P > 0.05). Both YKL-40 and chitotriosidase were found statistically significant higher in primary prostate cancer and BPH.
Conclusion: High serum YKL-40 levels in patients with primary prostate cancer indicate that YKL-40 may have a function in the progression of malignant diseases, whereas no significant elevation was observed in benign prostatic hyperplasia. Meanwhile, high serum chitotriosidase activity was observed only in patients with Gleason high grade, indicating possible macrophage involvement in cancer progression. Further studies are needed to elucidate the biologic role of YKL-40 in cancer aggressiveness and in progression of malignant diseases.