Expression of the fibroblast/macrophage marker 1B10 by spindle cells in Kaposi's sarcoma lesions and by Kaposi's sarcoma-derived tumor cells.
BACKGROUND
Kaposi's sarcoma (KS) is a tumor whose ontogenic origin remains a matter of contention. KS tissues are characterized by predominant expression of endothelial markers, while KS-derived cell cultures are usually characterized by expression of mesenchymal non-endothelial cell markers.


OBJECTIVE
In order to clarify the ontogenic origin of KS cells, we investigated the expression of the fibroblast/macrophage marker 1B10 in KS tissues (AIDS-associated KS, n = 9; classic KS, n = 6; iatrogenic KS, n = 6) and in KS-derived cell cultures.


RESULTS
1B10 was expressed by loosely distributed spindle-shaped cells in early 'patch-stage' KS and by a variable proportion of spindle cells in late 'plaque- and nodular-stage' KS. Using immunohistochemistry and immunoblot analysis, we found that, in vitro, reactivity for 1B10 was uniformly evidenced in fibroblasts and in KS-derived spindle cell cultures, irrespective of their histological or epidemiological setting. By contrast, vascular smooth muscle cells and endothelial cells were negative for 1B10.


CONCLUSIONS
These results suggest that the KS spindle cells isolated in vitro may represent a particular subpopulation of the KS spindle cell compartment.
Simonart
Thierry
T
Department of Dermatology, Erasme University Hospital, Brussels, Belgium. tsimonar@ulb.ac.be
Degraef
Chantale
C
Heenen
Michel
M
Hermans
Philippe
P
Van Vooren
Jean-Paul
JP
Noel
Jean-Christophe
JC
D000954:Antigens, Surface / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001706:Biopsy; D005347:Fibroblasts / Q000378:metabolism; D007150:Immunohistochemistry; D008264:Macrophages / Q000378:metabolism; D012514:Sarcoma, Kaposi / Q000378:metabolism* / Q000473:pathology; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology; D014407:Tumor Cells, Cultured
D000954:Antigens, Surface; D014408:Biomarkers, Tumor