Biomaterial-induced sarcomagenesis is not associated with microsatellite instability

Sarcomagenesis, in contrast to carcinogenesis, is poorly understood. Microsatellite instability has been implicated in the development of many cancers, in particular those associated with chronic inflammatory conditions. In an experimental animal model, rats developed not only a peri-implantational chronic inflammatory reaction, but also malignant mesenchymal tumors in response to different biomaterials. Therefore, it was the aim of our study to test if the development of biomaterial-induced sarcomas is characterized by a mutator phenotype. A multiplex-PCR approach was designed to screen biomaterial-induced sarcomas for the presence of microsatellite instability. Seven different microsatellite loci were tested in ten tumors for microsatellite instability using a fluorochrome-labelled multiplex-PCR and subsequent fragment analysis. All tumors provided a microsatellite-stable phenotype at all loci tested. Our data suggest that microsatellite instability is rarely or not at all a feature of malignant transformation of biomaterial-induced soft tissue tumors. Thus, there is no evidence that a mutator phenotype is a hallmark of biomaterial-induced sarcomagenesis.