YKL-40 expression in soft-tissue sarcomas and atypical lipomatous tumors

Abstract

Background and purpose YKL-40 is a glycoprotein that is expressed in many types of cancer cells. In some cancers, there is a correlation between high serum YKL-40 levels on the one hand and more aggressive disease and early death on the other. YKL-40 has never been studied in patients with soft-tissue sarcomas (STSs). We investigated whether YKL-40 is expressed in STS tissue and ascertained that the degree of expression is related to survival and/or the histological grade of the malignancy (FNCLCC).

Patients and methods We included archived tissue from 49 patients (40 with STS and 9 with atypical lipomatous tumor, 20 female and 29 male, mean age 58 (4–89) years) who were treated with tumor resection in 2004 or 2005 at the Department of Orthopedics, Rigshospitalet. The minimum length of follow-up with respect to survival was 5–7 years. Immunohistochemical analysis with anti-YKL-40 antibody using tissue microarray was performed on resected tumors, and a semiquantitative measure of the intensity of YKL-40 staining was performed.

Results 41 of the 49 tumors were positive for YKL-40, and of these, 36 had moderate to intense staining. 24 of the patients died within the follow-up period, and the intensity of YKL-40 staining was significantly higher in tumors from patients who had died in the follow-up period than in tumors from those who survived (p = 0.01). The staining intensity was different for the 3 grades of malignancy (p = 0.004): it was higher in highly malignant tumors (FNCLCC grade 2 and grade 3) than in low-malignancy tumors (grade 1).

Interpretation YKL-40 is expressed in soft-tissue sarcomas. There is a correlation between expression of YKL-40 in STS and both histological grade of the malignancy and survival. Whether or not YKL-40 expression is an independent prognostic variable could not be determined in the present study.

MLH collected clinical and pathological data, estimated staining intensity, analyzed data, and wrote the article. LHC estimated staining intensity and reviewed the article. MR performed YKL-40 staining and wrote the part of the text on YKL-40 staining. GSL wrote the protocol and reviewed the article. MMP supervised the project, analyzed data, and helped write the article.

Sincere thanks to consultant Søren Daugaard, MD, and to head of department Vera Timmermans Wielenga, MD, DMSc of the Department of Pathology, Rigshospitalet, for help and guidance with the materials and for stimulating discussions.

No competing interests declared.