Procollagen type III N-peptide and type IV collagen 7S-domain in the sera of breast cancer patients.

We investigated the usefulness of serum levels of procollagen type III N-peptide (P III P) and the type IV collagen, 7S-domain, (IV-C) as markers of recurrent and metastatic breast cancer. Serum P III P and IV-C levels were found to be significantly higher in patients who showed postoperative recurrence, with 76.9% of P III P-positive cancer bearing patients and 68.0% of IV-C-positive cancer bearing patients having metastases in the bone and/or liver. Furthermore, 66.7% of all patients with metastases in the bone and/or liver were P III P-positive and 75.6% were IV-C-positive. Patients with liver metastases were either P III P- or IV-C-positive, and the levels were higher than those in patients with bone metastases. Thus, a positive correlation of serum P III P and IV-C levels was observed. These findings suggest that both serum P III P and IV-C levels are useful markers of recurrent and metastatic breast cancer, especially of disease in the bone and/or liver.