Serum proteinase-like peptidase activities and proteinase inhibitors in women with breast disease.

The pre-treatment serum activities of several proteinase-like peptidases and the proteinase inhibitors, alpha 1-antitrypsin (alpha 1AT) and alpha 2-macroglobulin (alpha 2M), have been determined in 102 women with breast cancer and compared with those in 20 women with benign disease and in 30 healthy women of cancer bearing age. There were no significant differences in serum proteinase-like peptidase activities associated specifically with breast cancer. However, trypsin-like and plasmin-like activities were significantly lower than normal in women with breast disease. Serum alpha 1AT and alpha 2M levels were higher in patients with breast cancer than in healthy women or women with benign breast disease. These results indicate that, at presentation, breast cancer is not associated with abnormal serum levels of the proteinase-like peptidases studied, possibly as a result of an increase in the concentration of proteinase inhibitors.