No microsatellite instability, but frequent LOH in liposarcomas

To evaluate the significance of microsatellite instability (MI) and loss of heterozygosity (LOH) in the development of different histological subgroup s of liposarcomas, we examined 28 tissue-samples from 21 patients and the c orresponding non-neoplastic reference tissues. We investigated nine microsa tellite loci and detected no MI. LOH for at least one marker was observed i n 11 of 28 tumours (39%). Widespread allelic losses were a common character istic of pleomorphic liposarcomas. Well-differentiated variants did not sho w LOH (p<0.003). Our findings support the idea that liposarcoma subgroups a re defined by different spectra of genetic alterations. Inefficient DNA mis match repair does not seem to be involved in the oncogenesis of liposarcoma s.