title: Expression of YKL-40 by peritumoral macrophages in human small cell lung cancer.
abstract: YKL-40 is a 40 kDa protein with possible involvement in tissue remodeling, cell proliferation and angiogenesis. Elevated serum YKL-40 levels in patients with metastatic cancers (including small cell lung cancer (SCLC)) are associated with poor prognosis. The aim of this study was to identify the cellular source of YKL-40 in SCLC patient biopsies and in a panel of 20 human SCLC lines cultured in vitro and in vivo in nude mice. In general, the SCLC cell lines had no or very limited (human) YKL-40 expression, whereas, by RT-PCR a pronounced murine (i.e., stromal) YKL-40 expression was present in all tumors. YKL-40 mRNA transcripts were detected by in situ hybridization in 9 of 10 biopsies from SCLC patients, and in each case the signal was localized in the peritumoral stroma in cells of typical macrophage morphology (confirmed by a CD68 macrophage specific stain). No YKL-40 mRNA expression was found in the cancer cells, in macrophages infiltrating the solid tumor areas, or in non-malignant tissue. In conclusion, the predominant source of elevated serum YKL-40 in SCLC is peritumoral macrophages.
authors.affiliation: Laboratory of Experimental Oncology, Department of Molecular Pathology, University of Copenhagen, 11 Frederik V Vej, DK-2100 Copenhagen, Denmark.
authors.forename: Nanna
authors.initials: N
authors.lastname: Junker
authors.forename: Julia S
authors.initials: JS
authors.lastname: Johansen
authors.forename: Claus B
authors.initials: CB
authors.lastname: Andersen
authors.forename: Paul E G
authors.initials: PE
authors.lastname: Kristjansen
mesh_terms: D054392:Adipokines; D000818:Animals; D001324:Autoantigens; D018288:Carcinoma, Small Cell / Q000235:genetics* / Q000503:physiopathology*; D049109:Cell Proliferation; D000071451:Chitinase-3-Like Protein 1; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D037102:Lectins; D008175:Lung Neoplasms / Q000235:genetics* / Q000503:physiopathology*; D008264:Macrophages; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009374:Neoplasms, Experimental; D014407:Tumor Cells, Cultured
chemical_list: D054392:Adipokines; D001324:Autoantigens; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins