To clarify possible role of
cysteine cathepsin H, B and L in the proteolytic processes that contribute to the progression of
tumor growth in the thyroid, we studied their activity in lysosomes isolated from the tissue of
papillary carcinomas. It was shown that for these
enzymes there is a dependence of the changes in their activity on a number of
biological characteristics of the
tumors. Thus, the sharp increase in the activity ofcathepsin H observed in lysosomes of tissue
carcinomas category T2 and T3, with intra-and ekstrathyroid and lymphatic invasion of
tumor cells. An increase in the activity of
cathepsin B is set in the lysosomes of tissue heterogeneous follicular structure, especially in the presence of solid areas, in comparison with typical papillary
tumors and in the lysosomes of tissue
carcinomas in intrathyroid and
cathepsin L-at extrathyroid invasion. A common feature of the
enzymes is to increase the activity of
cathepsins in lysosomes of tissue nonencapsulated
papillary carcinomas. These
enzymes probably do not take part in the invasion of
tumor cells into blood vessels and in the mechanisms of
tumor metastasis to regional lymph nodes. The latter shows no changes in the activity of
cathepsins in lysosomes of tissue
carcinomas category N1. The results indicate the different role of
cathepsin H, B and L in thyroid
carcinogenesis, where each
enzyme has its specific function.