Comparative genomic hybridization study of paraffin-embedded dedifferentiated liposarcoma fixed with Holland Bouin's fluid.

Dedifferentiated and differentiated liposarcoma are characterized by 12q15 chromosomal amplification. Comparative genomic hybridization is a powerful tool able to detect DNA copy number changes in the genome. This technique has been widely used in frozen tumors and in some studies in paraffin-embedded tumors fixed with formalin. The purpose of this study was to demonstrate the ability of CGH to detect DNA copy number changes in the genome when the DNA was extracted from tissues fixed with Holland Bouin's fluid. Sixteen liposarcoma tumors both frozen and fixed in Holland Bouin's fluid were characterized by CGH. Eighty-one percent of the main chromosomal alterations detected in the frozen liposarcomas (amp 12q15, amp 6q23, amp 1p32, amp 16q22, +7, +8) were detected in the corresponding fixed tumors. The limitation of this technique when using Holland Bouin's fluid extracted DNA compared with formalin-extracted DNA was the yield of analyzable samples. Eighty-one percent of tumors fixed with Holland Bouin's fluid (13/16) were analyzable compared with 100% of formalin-fixed tumors (4/4). This study demonstrates that comparative genomic hybridization is a useful tool even if only fixed tissues (formalin and Holland Bouin's fluid tissues) are available, and that it allows more tumors to be analyzed in retrospective studies.