METCAM/MUC18 is a Biomarker and Therapeutic Target for Prostate Cancer.

BACKGROUND: METCAM/MUC18 may be a new serum biomarker for predicting malignant propensity of prostate cancer by using a modified lateral flow immune assay (modified LFIA), which used the extremely high affinity between biotin and streptavidin and two antibody combinations to increase the sensitivity and specificity of traditional LFIA. To increase the sensitivity and specificity to the highest degree, in this report we further improved this modified LFIA by using a new antibody combination, which includes a biotinylated home-made chicken antibody and a nano-gold conjugated rabbit antibody (MBS416853). MATERIALS AND METHODS: A calibration curve was established from two recombinant METCAM/MUC18 proteins (C-terminus GST as the positive control and NM-GST the negative control) and used for determining METCAM/MUC18 concentrations in 36 serum specimens from normal individuals and patients of benign prostatic hypertrophy (BPH) patients, prostatic intraepithelial neoplasia (PIN), and prostate cancer at various Gleason scores and after treatment. RESULTS: The data obtained were much better than the previously modified LFIA, traditional LFIA, and PSA test. Serum METCAM/MUC18 concentrations were higher in pre-malignant PIN patients than prostate cancer patients and both were higher than normal individuals, BPH patients, and treated patients. Serum METCAM/MUC18 concentrations were directly proportional to most serum PSA concentrations. CONCLUSIONS: The elevated serum METCAM/MUC18 concentration suggest that METCAM/MUC18 may be used as a novel biomarker for predicting the malignant potential of prostate cancer at the early premalignant (PIN) stage. Since METCAM/MUC18 could also drive the spreading of prostate cancer cells, METCAM/MUC18 may be a therapeutic target for the cancer.