ABSTRACT
We have measured the activity of the cysteine proteinase cathepsin B, the inhibitory activity of cysteine proteinase inhibitors and the amounts of cathepsins B, H and L in normal sera and sera from patients with breast cancer, as well as in tissue homogenates of tumorous and non-tumorous samples. The amounts of cathepsin B, determined by ELISA in tumour sera (n = 17) were significantly higher than the amounts determined in normal sera (n = 20). On the other hand, the differences in the amounts measured in tumour sera were not significant when compared with the known histopathological characteristics. In cytosols of breast cancer tumour tissue in general, the level of cathepsin H was higher than those of cathepsins B and L in all samples tested. In the same samples, at least a 10-fold increase of cathepsin B (activity and quantity) was detected in matched pairs (n = 20) of carcinoma and normal tissue of the same breast (p less than 0.01). The amount of cathepsin B correlated with the degree of malignancy inside the histological subtypes of invasive ductal carcinoma (n = 90, p less than 0.01). In addition, a negative correlation of values for cathepsin B with the involvement of regional lymph nodes (n = 75, p less than 0.01) was found inside the same group. In contrast, the activities of cysteine proteinase inhibitors did not correlate with any of the known clinical data. Our data provide further indirect evidence for the involvement of cathepsin B in the processes of tumour growth and metastasis in breast carcinoma. The follow-up studies will verify the prognostic value of these findings.
Subject(s)
Breast Neoplasms/enzymology , Carcinoma, Intraductal, Noninfiltrating/enzymology , Cathepsins/metabolism , Cysteine Endopeptidases , Endopeptidases , Breast Neoplasms/metabolism , Carcinoma, Intraductal, Noninfiltrating/metabolism , Cathepsin B/metabolism , Cathepsin H , Cathepsin L , Cysteine Proteinase Inhibitors/metabolism , Cytosol/enzymology , Female , HumansABSTRACT
In 20 matched pairs, an increase of all cathepsins was measured in carcinoma tissue compared with normal tissue of the same breast. On contrary, the mean value for kininogen was almost 2 fold lower than mean value determined in normal cytosols. From all proteins tested, the amount of cathepsin B correlated mostly with the degree of malignancy inside the group of invasive ductal carcinoma (n = 90, p < 0.01).
