Numerical and Structural Chromosomal Anomalies in Undifferentiated Pleomorphic Sarcoma

Background: Malignant fibrous histiocytoma (MFH) or undifferentiated pleomorphic sarcoma (UPS) is the most common soft-tissue sarcoma of late adult life. Further advances in genetic characterization are warranted. The aim of this study was to search for numerical and structural chromosomal anomalies in UPS. Materials and Methods: We investigated five sarcoma-specific chromosomal translocations, five oncogene amplifications as well as the numerical karyotype of 19 UPS samples and one UPS/MFH cell line (U2197) using FISH probes on interphase nuclei. Results: Our results demonstrate that chromosomal translocations involving CHOP, SYT, EWS, FUS and FKHR genes are absent. Furthermore, amplification of ERBB2 (10.5%) and MDM2 (10.5%) was observed whereas the EGFR, C-MYC and N- MYC genes were not amplified. Interestingly, predominant aneuploidies were found in eight chromosomes. Conclusion: The data demonstrate rarity of sarcoma-specific chromosomal breaks and oncogene amplifications in UPS, yet polysomic chromosomes appear more characteristically in this condition. Soft tissue sarcomas (STS) are malignant tumors of mesenchymal origin. With approximately 11,280 new cases diagnosed annually in the United States they comprise less than 1% of all malignancies (1, 2). Nevertheless, STS comprise a large heterogeneous group with more than 50 diagnostic entities described, the more common entities