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e21134 Background: Tryptase is a serin protease stored in mast cell granules that plays a role in tumour angiogenesis. Mast cells (MCs) can release tryptase following c-Kit receptor activation. On the other hand colo-rectal cancer (CRC) is a well-established angiogenesis dependent tumour and anti-angiogenic based therapy is a standard treatment in metastatic CRC. This preliminary study aims to assess tryptase serum levels in 51 CRC patients before and after radical surgery. Methods: In this study patients with stage B and C CRC (according to Astler e Coller staging system) were selected. Samples of blood were taken from CRC patients between 7 and 9 a.m.1 day before and 1 day after curative surgery. Venous blood was dispensed into a tube for serum (Becton Dickinson Hemogard Vacutainer Systems, Plymouth, UK). Tryptase levels were measured using the UniCAP Tryptase Fluoroenzymeimmunoassay (Pharmacia,Uppsala, Sweden). Primary tumour tissue were also evaluated in terms of MCs positive to tryptase by immunohistochemistry utilizing an anti-tryptase primary antibody (clone AA1; Dako, Glostrup, Denmark). Results: Mean ± s.d. tryptase level pre-tumour surgical resection was 6.37 ± 4.57 μg/L, and mean ± s.d. tryptase level post tumour surgical resection was 5.15 ± 3.82 μg/L. A statistically significant difference between pre-tumour surgical resection and post-tumour surgical resection tryptase level concentrations was found: p=0.000 by t-test. A statistically significant correlation between MCs positive to trypase and serum tryptase levels pre-surgical resection was also found (r=086; p=0.000) by Pearson’s analysis. Conclusions: This pilot report analyzes the possible significance of serum tryptase levels changes in CRC patients who underwent curative surgery. Our results demonstrated higher serum tryptase levels CRC patients suggesting the release of tryptase from MCs of primary CRC tissue. As expected, after radical surgical resection, serum tryptase levels had decreased. We suggest that tryptase may play a role as a new predictive biomarker in CRC patients. In this context several tryptase inhibitors such as gabexate mesilate and nafamostat mesilate might be evaluated as adjuvant treatment in clinical trials.

e21113 Background: Tryptase, a serine protease stored and released from mast cells granules has been identified as a new non-classical angiogenetic factor. Mast cells can release tryptase following c-Kit receptor activation. We have evaluated the correlations among the number of MCs positive to tryptase (MCDPT), the number of c-Kit receptor expressing cells (C-KREC) and microvascular density (MVD) in a series of 88 primary T1-3, N0-2 M0 female breast cancer by means of immunohistochemistry and image analysis methods. Methods: Six-micrometers thick serial sections of formalin-fixed and paraffin-embedded bioptic tumor samples were microwaved at 500 W for 10 min. and treated with a 3% hydrogen peroxide solution. Sections were incubated with primary antibodies: anti-tryptase (AA1; Dako, Glostrup, Denmark), anti-c-Kit receptor (A4502;Dako, Glostrup, Denmark) and anti-CD34 (QB-END 10; Bio-Optica Milan, Italy). In serial sections MVD, MCDPT and C-KREC were counted by means of image analysis at x400. Results: Data demonstrated a significantly (r= ranging from 0.71 to 0.91; p: ranging from 0.001 to 0.003 by Pearson’s analysis respectively) correlation between MVD, MCDPT and C-KREC to each other. Conclusions: Published in vitro data suggest that tryptase induce angiogenesis in vascular endothelial cells and breast cancer cells lines. According to these data we shown that MVD, MCDPT and C-KREC paralleled to each other suggesting a role in in vivo breast cancer angiogenesis. In this context several tryptase inhibitors such as gabexate mesilate or nafamostat mesilate might be evaluated in clinical trials as a new antiangiogenetic approach.

e21032 Background: Tryptase, a serine protease stored and released from mast cells (MCs) granules has been identified as a new nonclassical angiogenetic factor and it is an agonist of the proteinas...