Circulating levels of CSF-1 (M-CSF) a lymphohematopoietic cytokine may be a useful marker of disease status in patients with malignant ovarian neoplasms.

We have previously reported our observations of epithelial tumor cell expression of transcripts and protein antigens of CSF-1 and transcripts of a protein closely related--if not identical--to the CSF-1 receptor in ovarian and endometrial neoplasms in vivo and in vitro. In the present communication, we extend these investigations to analyze the clinical utility of determinations of plasma CSF-1 concentrations in 125 samples from 33 patients with ovarian neoplasms and one patient with benign endometriosis. We observed that plasma CSF-1 levels in patients with active and recurrent neoplastic disease were markedly elevated and follow changes in disease status in individual patients. These and other results presented in this communication suggest that not only could CSF-1 be a useful circulating tumor marker in ovarian carcinoma patients, but also that in combination with measurements of other markers--such as CA-125--determinations of plasma CSF-1 levels might actually improve the accuracy of "tumor marker"-based assessments of disease status in patients with malignant ovarian neoplasms.