This study was performed to identify gene expression differences in not otherwise specified soft tissue sarcomas (NOS, malignant fibrous histiocytomas) and correlate them to histological findings and the clinical course. RNA was isolated and differential gene expression was analysed by the microarray technique. We used microarrays to detail the global gene expression differences between primary soft tissue sarcoma samples, harvested intraoperatively. Keywords: response to chemotherapeutic agent Overall design: We compared the gene expression of ten different tumor samples of MFH/NOS sarcoma to determine global gene expression differences by microarray analysis.