[Gastrointestinal stromal tumors]

Primary extragastrointestinal stromal tumor arising in the vaginal wall: Significant clinicopathological characteristics of a rare aggressive soft tissue neoplasm

Gastrointestinal (GI) stromal tumor is the most common mesenchymal neoplasm of the GI tract but also occurs with a lower frequency in extragastrointestinal regions and is called extragastrointestinal stromal tumor (EGIST). We report an unusual case of EGIST presenting as a vaginal mass. A 41-year-old woman presented with a gradually enlarging vaginal mass for the last 2 years. Physical examination revealed an elliptical, non-tender mass about 7.5 cm × 7 cm in size in the posterior vaginal wall and was resected completely. Under histological examination, the tumor showed a spindle cell type with coagulation necrosis, hemorrhage and high mitotic count. Immunohistochemical analysis revealed tumor cells were positive for DOG1, CD117, CD34 and p53 protein. Ki-67 labeling was 8%. Genetic analysis showed a deletion of exon 11 of the c-kit gene at codons 557-558. EGISTs should be kept in mind in the differential diagnosis in patients presenting with solid mass of the vaginal wall.

Biomarkers for anti-angiogenic therapy in cancer

Angiogenesis, the development of new vessels from existing vasculature, plays a central role in tumor growth, survival, and progression. On the molecular level it is controlled by a number of pro- and anti-angiogenic cytokines, among which the vascular endothelial growth factors (VEGFs), together with their related VEGF-receptors, have an exceptional position. Therefore, the blockade of VEGF signaling in order to inhibit angiogenesis was deemed an attractive approach for cancer therapy and drugs interfering with the VEGF-ligands, the VEGF receptors, and the intracellular VEGF-mediated signal transduction were developed. Although promising in pre-clinical trials, VEGF-inhibition proved to be problematic in the clinical context. One major drawback was the generally high variability in patient response to anti-angiogenic drugs and the rapid development of therapy resistance, so that, in total, only moderate effects on progression-free and overall survival were observed. Biomarkers predicting the response to VEGF-inhibition might attenuate this problem and help to further individualize drug and dosage determination. Although up to now no definitive biomarker has been identified for this purpose, several candidates are currently under investigation. This review aims to give an overview of the recent developments in this field, focusing on the most prevalent tumor species.