title: Prognostic implications of immunohistochemically detected YKL-40 expression in breast cancer.
abstract: BACKGROUND
  YKL-40 has been implicated as a mediator of collagen synthesis and extracellular matrix re-modeling as well as mitogenesis. Elevated serum levels of YKL-40 have been associated with worse survival in a variety of malignancies including breast cancer. We wished to determine if immunohistochemically detected expression had prognostic implications in breast cancer.
  
  
  METHODS
  A prospectively collected database of breast cancer patients treated at the University Hospital of Newark was used for analysis. Immunohistochemistry was performed on archived tumor tissue from 109 patients for whom full clinical information and follow up was available.
  
  
  RESULTS
  YKL-40 expression was noted in 37 patients (34%). YKL-40 immunoreactivity significantly correlated with larger tumor size, poorer tumor differentiation, and a greater likelihood of being estrogen and/or progesterone receptor negative. No significant correlation was demonstrated between YKL-40 status and nodal stage. At a mean follow up of 3.2 years, disease-free survival was significantly worse in the subset of patients whose tumors demonstrated YKL-40 expression compared to the non-expressors. In multivariate analysis, YKL-40 status was independent of T-stage and N-stage in predicting disease recurrence.
  
  
  CONCLUSIONS
  Immunoreactivity for YKL-40 was a significant predictor of breast cancer relapse in this subset of patients. This was independent of T or N-stage and suggests that tumor immunohistochemistry for this protein may be a valuable prognostic marker in breast cancer.
authors.affiliation: Department of Surgery, New Jersey Medical School/University of Medicine and Dentistry of New Jersey, Newark, NJ, USA. shkim1@geisinger.edu
authors.forename: Steve H
authors.initials: SH
authors.lastname: Kim
authors.forename: Kasturi
authors.initials: K
authors.lastname: Das
authors.forename: Shahla
authors.initials: S
authors.lastname: Noreen
authors.forename: Frederick
authors.initials: F
authors.lastname: Coffman
authors.forename: Meera
authors.initials: M
authors.lastname: Hameed
mesh_terms: D054392:Adipokines; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood*; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000097:blood* / Q000401:mortality / Q000473:pathology*; D000071451:Chitinase-3-Like Protein 1; D015331:Cohort Studies; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D037102:Lectins; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D016019:Survival Analysis
chemical_list: D054392:Adipokines; D014408:Biomarkers, Tumor; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins