Establishment and characterization of carcinosarcoma cell line of the human uterus

Background. The histogenesis of carcinosarcoma is still unknown. Methods. A new human uterine cell line, EM‐TOKA, derived from a carcinosarcoma of the uterus, has been passed successfully in cell culture for more than 2 years. The cell line was established on April 11, 1989, in a uterine tumor of a 64‐year‐old Japanese woman who had a simple hysterectomy. The pathologic examination of the cultured material showed papillary and tubular adenocarcinoma (carcinomatous elements) and spindle‐shaped fiber cells and chondrosarcoma (sarcomatous element). Results. The cultured cells showed a cell‐to‐cell variability and at least five cell types, which included columnar cell, small epithelial cell, moderately sized or large epithelial‐like cell, malignant tumor giant cell, and spindle cell types. The EMTOKA cells were transplantable to nude mice and produced tumors that consisted of the same carcinomatous and sarcomatous elements as those observed in the original tumor. The double labeling analysis of vimentin and cytokeratin showed that a large number of cultured cells had positive results for vimentin and a small number of cells had positive results for cytokeratin. Only a very small number of EMTOKA cells stained for vimentin and cytokeratin. The number of cells that expressed neither vimentin nor cytokeratin was very low. Conclusions. These findings may support the hypothesis that a uterine carcinosarcoma may be derived from a single stem cell that does not express both of the intermediate filaments.