Abnormal Profile of Serum Proteinase Inhibitors in Cancer Patients

Abstract We reported previously that an antitryptic glycoprotein, EDC1 ( M r 27,500), which is immunologically related to the normal serum proteinase inhibitor, inter-α-trypsin inhibitor (IATI), is excreted in large quantities in the urine of metastatic cancer patients. We have now measured immunoreactive titers of urinary EDC1 and five serum proteinase inhibitors (including IATI) in 16 patients with hematological cancers, 9 patients with various solid tumors, and 32 healthy subjects. The mean urinary EDC1 levels were 22-fold greater in all cancer patients as compared to normals [187.0 ± 136.6 (S.D.) versus 8.4 ± 8.2 mg/g creatinine; p 1 -proteinase inhibitor (also called α 1 -antitrypsin), α 1 -antichymotrypsin, and C1 inactivator averaged 152, 237, and 165% of the normal values, respectively ( p 2 -macroglobulin levels were unchanged, and immunoreactive IATI levels were depressed (75% of the normals; p 1 -proteinase inhibitor level, the serum antitryptic capacity of the cancer group averaged only 50% of the normal group ( p 1 -proteinase inhibitor in the cancer group is functionally inert.