Serum tryptase, mast cells positive to tryptase and microvascular density evaluation in early breast cancer patients: possible translational significance

BACKGROUND: Tryptase is a serine protease released from mast cells that plays a role in tumor angiogenesis. In this study we aimed to evaluate serum tryptase levels in 105 female early breast cancer patients before (STLBS) and after (STLAS) radical surgical resection, mast cell density positive to tryptase (MCDPT) and microvascular density (MVD). METHODS: STLBS and STLAS were assessed using the UniCAP Tryptase Fluoroenzyme immunoassay. Tumor sections were immunostained with a primary anti-tryptase antibody and an anti-CD-34 antibody by means of immunohistochemistry. RESULTS: The mean ± 1 standard deviation STLBS and STLAS was 7.18 ± 2.63 μg/L, and 5.13 ± 2.21 respectively and a significant difference between mean levels was found (p = 0.0001) by student t-test. A strong correlation between STLBS and MVD (r = 0.81, p = 0.0001); STLBS and MCDPT (r = 0.69, p = 0.003); and MCDPT and MVD (r = 0.77; p = 0.0001) was found. CONCLUSIONS: Results demonstrated higher STLBS in breast cancer patients, indicating an involvement of MC tryptase in breast cancer angiogenesis. Therefore, serum tryptase levels may play a role as a novel surrogate angiogenic marker predictive of response to radical surgery in breast cancer patients. In this patients setting, it’s intriguing to hypothesize that tryptase inhibitors might be evaluated in clinical trials.