Abstract

This experiment was performed to elucidate the cytologic origin of chemically induced MFH in Wistar rats. The tumor was produced by injections of DMBA(9,10-dimethyl-1,2-benzanthracene). With the produced MFH, cell culture and cloning were performed, followed by establishment of a cell strain, which was investigated by immunohistochemical and electron microscopic studies. The results were as follows. A) By immunohistochemistry of the tumor tissue, fibroblastic cells were positive for MEP-1(specific antibody for fibroblastlike cell of MFH, Takeya, 1993) and Anti-hPH(beta)(Anti-prolyl 4-hydroxylase beta), but negative for TRPM-3 and F4/80. Histiocytelike cells were positive for TRPM-3 and F4/80, but negative for MEP-1 and Anti-hPH(beta). In immunoelectron microscopy, normal spleen macrophage showed linear reactivity in cell membrane for TRPM-3, whereas histiocytelike cells of the tumor disclosed negative reaction. B) At 5 weeks of the primary tumor cell culture, the cells exhibited typical storiform pattern of MFH. C) The established cell strain revealed immunoreactivity for MEP-1 and Anti-hPH(beta), but negative for TRPM-3. The cloned tumor cells showed morphologic characteristics of undifferentiated fibroblastic cell. Latex particle (0.80 micrometer size) phagocytosis was negative in the cloned cell strain. The results of the current study support the concept that principal component cells of MFH is of fibroblastic cell origin.

• Keywords: Malignant fibrous histiocytoma;Histogenesis;Cell strain;MEP-1;Anti-prolyl 4-hydroxylase beta