Establishment of a novel human dedifferentiated liposarcoma cell line, FU-DDLS-1: conventional and molecular cytogenetic characterization.

A number of human cell lines derived from well-differentiated, myxoid/round cell, or pleomorphic liposarcoma have been described. To our knowledge, however, no human cell line established from dedifferentiated liposarcoma has been reported. In this study, we established a new human cell line, FU-DDLS-1, which originated from a dedifferentiated liposarcoma arising in the retroperitoneum of a 61-year-old man. This cell line was characterized by immunocytochemistry, conventional banding analysis, fluorescence in situ hybridization with chromosome painting probe, and comparative genomic hybridization (CGH). FU-DDLS-1 cells were spindle or polygonal shaped and possessed oval nuclei and slender cytoplasmic processes. The cultured cells were successfully maintained in vitro for over 90 passages over more than 30 months. The histologic features of heterotransplanted tumors in severe combined immunodeficiency mice were essentially the same as those of the original nonlipogenic sarcoma resembling a malignant fibrous histiocytoma. Both in vitro and in vivo, the cells exhibited immunopositive reaction for mdm2 and p53 proteins. Cytogenetically, FU-DDLS-1 displayed a hypertetraploid karyotype with giant marker chromosomes composed partly of chromosome 12 material. In addition, CGH analysis demonstrated that DNA sequence copy number changes including a gain of 12q12-q21 detected in FU-DDLS-1 were essentially the same as those in the original sarcoma. The FU-DDLS-1 cell line, which exhibits the unique conventional and molecular cytogenetic characteristics of dedifferentiated liposarcoma, should be a particularly useful model for studying the molecular pathogenesis of human dedifferentiated liposarcoma.