Pathology of gastrointestinal stromal tumours with accent to prognostic criteria
This article is a review of actual consideration on pathomorphological and genetic parameters of GIST associated with their prognosis and prediction to target therapy. GIST are new separate oncological entities with well-determined morphological and molecular biological characteristics with oncogenic mutation of the tyrosine kinase and have good response to blocking tyrosine-kinase therapy. The different grade of malignancy and some deviation from conventional pathology (absence of KIT mutation, appearance of other mutation such as PDGFRA) require implementation of more accurate pathomorphological and genetic prognostic and predictive criteria with the respective changes in standard diagnostic practice. Large-scale studies indicated that the tumour localisation affects the risk of tumour recurrence and progression. Small intestinal tumours are more aggressive than gastric GIST and this should be included as a risk factor. This gave proof supporting the inclusion of the tumour site as an important parameter considered into the risk assessment of resected GIST. New ESMO recommendations for diagnostic procedures, treatment and follow-up include the obligatory site of tumour, its size and mitotic index. The presence of specific mutations has predictive role and the application of mutation analysis has been recommended in metastatic tumours. Many other biological and pathohistological characteristics are being investigated but their prognostic and predictive role has not been proven yet.