Leiomyosarcomas and most malignant fibrous histiocytomas share very similar comparative genomic hybridization imbalances: An analysis of a series of 27 leiomyosarcomas

Twenty-seven tumor samples with a diagnosis of leiomyosarcomas (LMS) were c haracterized by comparative genomic hybridization. The results were compare d with immunohistochemical analysis of the smooth muscle profile of the tum ors and expression of the RB1 gene protein. The comparative genomic hybridi zation profiles suggested that 7 of the 27 tumors might have been misclassi fied. High levels of DNA amplification were detected in 20 different small regions and recurrently involved bands 1p34, 1q21, 12q13-15, 17p, and 22q. Most recurrent simple gains were noted at sites such as 1p3, 1q21, 15q12-15 , 16p, 17p and 17q, 19, 20q, 22q, and Xp. Significant losses of chromosome 13 were detected in 19 of the 27 tumors with a putative common region of lo ss in bands 13q14-21. Losses of chromosomes 1q, 2p and 2q, 4q, Sp, 10p and 10q, 11p and 11q23, and 16q were also highly recurrent. A comparative analy sis between the most frequent genomic imbalances observed in this study of LMS and the genomic imbalances observed in a large proportion of malignant fibrous histiocytomas (MFH) from a previous study demonstrated that both ty pes of tumors had similar recurrent imbalances. Although MFH were once thou ght to be a separate member of the soft tissue sarcoma family, our observat ions support the hypothesis that MFH are a morphologic modulation in the tu moral progression of other sarcomas, particularly LMS.