A small number of human epithelioid sarcoma cell lines have been reported, but their characterization at a molecular cytogenetic level is not well known. In this study, a new permanent human cell line, FU-EPS-1, derived from a metastatic epithelioid sarcoma developing in the axillary lymph node of a 21-year-old man is described. This cell line was characterized by use of immunocytochemistry, conventional G-banding analysis, spectral karyotyping (SKY) and comparative genomic hybridization (CGH). FU-EPS-1 cells were round, polygonal or spindle shaped with an abundant cytoplasm, and have been maintained continuously in vitro for over 100 passages during more than 15 months. Histologic features of the heterotransplanted tumors in severe combined immunodeficiency mice were essentially the same as those of the original tumor, revealing a multinodular proliferation of eosinophilic epithelioid and spindle cells. Both in vitro and in vivo, the cells were immunopositive for cytokeratins (AE1/AE3 and CAM5.2), epithelial membrane antigen, vimentin and CD34, but were negative for desmin, S-100 protein, CD31 or factor VIII-related antigen. By G-banding and SKY analyses, FU-EPS-1 revealed a hyperdiploid karyotype with the following chromosomal abnormalities: +i(5)(p10), -8, +13, der(13)t(8;13)(q?;p11), +der(19)t(9;19)(?;?) and del(22)(q13). In addition, CGH analysis identified gains of 5p, 9q, 19q and 22q and a loss of 8p. This study demonstrates the value of molecular cytogenetic techniques such as SKY and CGH in defining genomic alterations in greater detail. The FU-EPS-1 cell line will be exceedingly useful for biologic and molecular pathogenetic studies of human epithelioid sarcoma.