QUANTITATIVE-ANALYSIS OF TRYPTASE AND CHYMASE CONTAINING MAST-CELLS IN BENIGN AND MALIGNANT BREAST-LESIONS

The aim of our work was to study the number and distribution of trypta se- and chymase-containing mast cells in benign and malignant breast l esions. Tryptase positivity reflects the total number of mast cells, w hereas chymase is not present in all mast cells. Active forms of trypt ase and chymase were demonstrated enzymo histochemically in 30 benign and 98 malignant fresh frozen breast lesions, which were graded and an alysed morphometrically and statistically. The exclusive presence of t ryptase and chymase in mast cells was confirmed in 5 cases by a sequen tial double-staining method. In benign lesions, the number of mast cel ls exhibiting tryptase activity was similar to that of chymase active mast cells. Malignant tumours, however, had 2 to 3 times more tryptase -containing than chymase-containing mast cells, while the number of ma st cells with tryptase activity was significantly higher (p < 0.02) th an in benign lesions, In malignant lesions, tryptase-containing mast c ells were concentrated at the tumour edge, i.e., the ''invasion zone,' ' whereas chymase-containing mast cells were not increased in this are a. (C) 1997 Wiley-Liss, Inc.