Characteristics of cell lines established from a mixed mesodermal tumor of the human ovary. Carcinomatous cells are changeable to sarcomatous cells.

Four clonal cell lines of two types were established from a heterotransplantable mixed mesodermal tumor of the human ovary. Biologic properties of these cell lines (designated CS-C1, CS-S1, CS-S2, and CS-S3) were examined. Cells of one line (CS-C1) had an epithelioid shape and grew in monolayers (C-type). The cells showed alkaline phosphatase activity, stained positively with antikeratin antiserum, and had an ultrastructure with carcinomatous characteristics. Cells of the other three cell lines (CS-S1, CS-S2, and CS-S3) had an irregular shape and grew in multilayers (S-type). Most of the cells did not show alkaline phosphatase activity. They stained, not with antikeratin antiserum, but in fibrillar array with antifibronectin antiserum. Their ultrastructure had sarcomatous characteristics. By low cell density cultures, S-type sublines arose from CS-C1 cell line, but no C-type sublines arose from CS-S1 cell line. These findings may support the theory of the combination tumor as the cytogenesis of mixed mesodermal tumor of the ovary; they also suggest the conversion of carcinomatous cells to sarcomatous cells.