We analysed 21 samples of malignant fibrous histiocytoma (MFH) distinguished into the two principal morphological categories ('spindle cell' and the 'pleomorphic' subtypes). The aim of our study was to verify if a distinction between the two subclasses of MFH in terms of expression/activation of protein profiles could support and extend the morphological criteria. For this purpose, we carried out an immunohistochemical and immunoblotting analysis of proteins that could be relevant in sarcoma biology and potential diagnostic and therapeutical targets such as matrix metalloproteinases (MMPs) and molecules related to adhesive and proliferative properties. Our analysis revealed that MMP-1, MMP-9 expression and p27(kip1) cytoplasmic localisation can be considered valid parameters in the classification and potential explanation of the aggressive behaviour of this non-homogeneous group of MFH.