Ultrastructural, immunocytochemical, and cytogenetic characterization of a human epithelioid sarcoma cell line (RM-HS1).

A cell line (RM-HS1) derived from a human epithelioid sarcoma was established in tissue culture. Ultrastructurally, the cells show features of those found within the primary tumor. A mixed mesenchymal-epithelial phenotype, defined by reactivity with antibodies to epithelial membrane antigen and to vimentin and keratin intermediate filaments, was found in the tumor, and a similar phenotype persisted in the cultured cells. Cytogenetic analysis revealed a mode of 66 chromosomes. With the use of a variety of banding techniques together with in situ hybridization of a 3H-labeled molecular probe for 18s and 28s ribosomal RNA genes (pX1r101), the karyotypes were shown to contain extensive numerical and structural rearrangements, with up to 24 marker chromosomes.