ABSTRACT
PURPOSE: Serum levels of the polypeptide chemokine C-C motif ligand 2 (CCL2) have previously shown potential as a prostate cancer diagnostic and prognostic biomarker. Plasma CCL2 levels may be superior to serum levels as a biomarker because of their potentially lower signal-to-noise ratio. MATERIALS AND METHODS: Before initiating a large comparative study of plasma and serum CCL2 levels, we performed a prospective, diagnostic pilot study Of 133 individuals from a clinically relevant population. CCL2 plasma levels were measured using a validated assay kit. Plasma was obtained independently of digital rectal examination. RESULTS: In this pilot study, we found no relationship between CCL2 plasma values and risk of proven prostate cancer, whereas previous studies found a strong diagnostic relationship between CCL2 serum values and prostate cancer. CONCLUSION: Our contribution to the existing literature strengthens the idea that early in the pathological process, CCL2 mainly circulates in large, membrane-enclosed compartments, whereas plasma CCL2 levels increase markedly during disease progression. We conclude that whereas plasma CCL2 levels are not useful as a diagnostic measure, a ratio of CCL2 plasma to serum levels may prove useful as a marker of disease progression, which warrants further study.
