Poorly differentiated mast cell tumour and neuro and genesis:lack of correlations between microvessel density and mast cell density

Angiogenesis, a multistep process regulated by positive and negative soluble factors, plays an important role for tumour progression (growth, invasiveness and metastasis).A mutuai stimulation occurs between tumour cells and neoplastic cells by paracrine mechanism. Host inflammatory cells can also secrete angiogenic factor. Severa/experimental researches suggest that increase of mast-cells density (MCD) is joined with increase of microvessel density (MVD). To evaluate the putative role of MCD in the angiogenic process we studied, for the first time, a series of 16 poorly differentiated grade 3 (G3) dog mastocytomas. Mast celi tumours (MCT) are common in dog with an incidence much higher than those found in human, consequently dog MCT can be a va/id mode/ to study angiogenic process. Seria/ sections for each MCT were processed both with toluidine bleu specific for MC identification and immunohistochemical method using the polyclonal antibody anti FVIII - RA as an endothelial marker. Slides were evaluated using an image analysis system (Quantimet 500 Leica). The three most vascular areas "hot spots" in each tumour tissue were selected and individuai vessels and individuai mast cells were counted at 400x. Both MVD and MCD means and standard deviation (s.d.) were determined both for each tumour and in the gfobal series. MVD and MCD means value were l 8 ± l l and l 06 ± 97 respectively. The regression anafysis (pearson's test) between MVD and MCD failed to show any correfation (p= n.s.). On these basis we speculate that cutaneous malignant mastocytomas are fow vascufarized tumour and neoplastic mast cel/s shoufd not playa major role in the angiogenic process.