Establishment and characterization of neoplastic cells from a malignant fibrous histiocytoma. A possible stem cell line.

Using the semisolid agar method, neoplastic three clones were isolated from a malignant fibrous histiocytoma. All clones represented morphologically only one type of cells having fine structure similar to that of histiocyte with multiple filopodia. The clones carrying Fc- and C3-surface receptors showed marked immunophagocytosis. They were positive for acid phosphatase, nonspecific esterase, and alpha-1-antitrypsin. These clones were able to display the potential for production of collagenous matrix. Moreover, inoculations of the each clone into nude mice resulted in productions of malignant fibrous histiocytoma with pleomorphic pattern. These tumors were composed morphologically of various types of cells such as immature, histiocyte-like, fibroblast-like, and multinucleated giant cells. These morphologic alterations of histiocytes occurred in all of the three clones in vitro. These findings suggest that the cloned cells established from the malignant fibrous histiocytoma are neoplastic histiocytes with capability to form various types of cells, a possible stem cell.