Microvessel surface correlates with ki67 expression in extragastrointestinal stromal tumours – A case series

Introduction. Neoplastic microenvironment represents a frequently studied subject in numerous studies. Angiogenesis, as a part of it, is a prognostic factor and a therapeutic target in several neoplastic diseases. Cases presentation. We describe the angiogenetic process in a small series of extra gastrointestinal stromal tumours (EGISTs) and corelate it with the proliferation index. We retrospectively searched our institutions databases for EGIST cases. The resulting data were reviewed by two pathologists. Immunohistochemistry (IHC) was performed to highlight the vascular structure of the tumours and determine the proliferative index using ki67 staining. Subsequently, the whole slide scanned digital images were used to assess micro vessel density and vascular surface. Statistical analysis of measurements data yielded a negative correlation between the tumour proliferative index and vascular surface normalized to examined surface of the tumour (r=-0.5506 and p=0.0051). A correlation between micro vessel density and proliferative index of the tumour could not be established in our series (p =0.035). Conclusions. Highly proliferative EGISTs have a reduced micro vessel surface compared to low grade tumours, possibly due to a limited development rate of the angiogenesis during the tumours’ growth. Due to the rarity of this sarcoma, our study is limited by the small number of cases, as well as by the preanalytical procedures performed on the tissue that may alter the vascular area in different manners. Further studies on larger series are needed to confirm our results and to investigate other morphological parameters, to assess the utility of anti-angiogenic therapies.