[Studies on the clinical significance of type III procollagen peptide in sera as a tumor marker in patients with ovarian tumors].

Usefulness of type III procollagen peptide (P-III-P) in sera as tumor marker was investigated in patients with ovarian tumors. A concentration of P-III-P in sera was measured by radioimmunoassay. The mean P-III-P values for 72 females as healthy controls were 8.5 +/- 2.7 ng/ml. Therefore, the cut-off value (Mean + 2 SD) was set at 13.9 ng/ml. The positive rates of healthy controls were 4.2%. For patients with benign ovarian tumors, the mean P-III-P values were 8.7 +/- 2.3 ng/ml, and the positive rates were 0%. For patients with ovarian tumors of borderline malignancy, the mean P-III-P values were 8.0 +/- 1.5 ng/ml, and the positive rates were 0%. In both of benign and borderline malignant cases, the false positive rates of tumor markers such as TPA, IAP, CA-125 and CA 19-9 were relatively high. For patients with malignant ovarian tumors, the mean P-III-P values were 19.7 +/- 9.9 ng/ml at pretreatment, 10.4 +/- 1.0 ng/ml at post-treatment and 17.3 +/- 1.9 ng/ml at recurrence. The positive rates were 69.2% at pre-treatment, 0% at post-treatment and 100% at recurrence. In relation of histology, the positive rates were particularly high in patients with serious cystadenocarcinoma and embryonal carcinoma. In conclusion, P-III-P in sera was very useful as tumor marker in diagnosis of malignant ovarian tumors, while it was not aided to detect the early cancers.