[Molecular biological evaluation of prognostic parameters in GIST. Development of an integrative model of tumor progression].

Prognosis evaluation in gastrointestinal stromal tumors (GIST) is currently based on tumor diameter, mitotic counts and anatomic localisation. There are two risk classifications as well as the first ever TNM classification for GISTs, whereby the risk classification according to the Armed Forces Institute of Pathology (AFIP) has the best correlation with clinical follow-up according to own experiences. "Very low/low risk" GISTs are almost benign, while the majority of "high risk" GISTs metastasize and benefit from adjuvant therapy. Careful evaluation of mitotic counts in 50 high-power fields is of particular relevance for correct risk classification. Apart from these classical prognostic factors, many molecular genetic parameters with correlation to follow-up have been evaluated and may help to improve prognosis evaluation of GISTs in the future. Since most of the molecular genetic parameters are associated or even determined by the clinico-pathological parameters, an integrated model for tumor progression of GISTs is helpful to interpret the different factors in correlation to one another. In particular for "intermediate risk" GISTs, additional parameters are needed for improved prognosis evaluation.