Abstract
We describe the newly established cell line CS-99 derived from a uterine carcinosarcoma retaining features of the sarcomatous phenotype in vitro. CS-99 cells exhibit a mesenchymal morphology with predominantly spindle-shaped cells at nonconfluence turning to pleomorphic appearance at confluence. The mesenchymal phenotype was evidenced immunohistochemically by strong vimentin and moderate SM-actin, which was similar to the sarcomatous component of the primary tumor. P53 was overexpressed in a subset of CS-99 cells. Epithelial membrane antigen was moderately expressed whereas other markers including pan CK, CK 5/6, CK 34, epidermal growth factor receptor, desmin, carcinoembryonic antigen, S100, KIT, ERBB2, and the hormone receptors, estrogen receptor and progesterone receptor revealed either weak or no specific staining in CS-99 cells. High self-renewal capacity corresponded to the population doubling time of 23 h in high passage. CS-99 cells were able to develop three-dimensional tumor spheroids in vitro. Cytogenetic analysis and multicolor fluorescence in situ hybridization of CS-99 demonstrated an almost stable karyotype including numerical changes +8, +18, and +20 and translocations, amongst others der(1)t(1;2), der(1)t(1;7), der(2)t(2;19), der(5)t(5;8), and der(5)t(5;14). Taken together, the cell line CS-99 exhibits strong growths dynamics and a complex but stable karyotype in higher passages, and can be further a useful in vitro model system for studying tumor biology of carcinosarcomas.