Inflammatory sarcomas. The cat as a good model of pathogenesis and therapy

Feline injection site sarcoma (FISS) is a particular form of soft tissue tumour associated to a chronic inflammatory process that probably acts a fundamental role in the tumour pathogenesis. Many analogies are observed between FISS and human nodular fasciitis (NF), a pseudosarcomatous lesion, and myxoinflammatory fibroblastic sarcoma (MFS), another characteristic soft tissues tumour of man. All these lesions are morphologically and clinically very similar, the possible causes proposed and investigated include trauma/inflammation, genetic predisposition, exposure to radiation or certain chemicals, all of which may stimulate the tissues to divide more rapidly than normal. In human cases, as recently described in cat, oncogenes, tumor suppressor genes, and other cellular genetic defects have been identified and these exhibit an association with connective tissue sarcomas. In the authors experience feline and human lesions are also similar for COX-2 protein expression and for NF-ĸB pathway activation. These similarities suggest that cat may represent a good model to study inflammatory-induced soft tissue proliferations in man and to investigate the role of the cell-mediated Th1 type and Nk immunoresponse in the control of tumour spread and recurrences, and in patients outcome.