Plasma YKL-40, as a prognostic tumor marker in recurrent ovarian cancer

BACKGROUND: YKL-40, a member of family 18 glycosyl hydrolases, is secreted by cancer cells. The function of YKL-40 in cancer diseases is unknown, but it is a growth factor of connective tissue cells and probably has a role in inflammation and remodeling of the extracellular matrix, a process also involved in metastatic malignant diseases. High serum YKL-40 has been associated with poor prognosis for patients with colorectal and recurrent breast cancer. AIM OF THE STUDY: The purpose of the present study was to examine the prognostic value of plasma YKL-40 in patients presenting with recurring ovarian cancer. METHODS: YKL-40 was determined by ELISA in plasma samples from 73 patients with relapse of ovarian cancer shortly before start of second-line chemotherapy. The endpoint used was death because of ovarian cancer. RESULTS: Plasma YKL-40 was increased in ovarian cancer patients (median 94 micro g/L, range 20-1970 micro g/L) compared with age-matched controls (33 micro g/L, range 20-130 micro g/L) (p < 0.001). Fifty-five per cent of the patients had a plasma YKL-40 level above the upper normal 95th percentile of controls. Patients with high plasma YKL-40 (i.e. > 130 micro g/L or > 160 micro g/L) at the time of relapse had significantly shorter survival than patients with normal levels (respectively p = 0.007 and p = 0.004). Plasma YKL-40 proved to be an independent prognostic factor in a multivariate Cox analysis (YKL-40 > 160 micro g/L; HR = 2.27) (p = 0.006), including serum CA-125 and clinical/histological parameters. CONCLUSION: High plasma YKL-40 is related to short survival in patients with recurrent ovarian cancer.