IMMUNOFLUOROMETRIC ASSAY OF PEPSINOGEN-C AND PRELIMINARY CLINICAL-APPLICATIONS

We developed mouse monoclonal antibodies (Abs) against pepsinogen C wi th highly purified antigen isolated from gastric mucosa. The Abs were used to construct a two-site sandwich-type assay for pepsinogen C with time-resolved fluorometry as a detection technique. The assay has a d etection limit of 0.1 mu g/L and is precise (within-run and day-to-day CVs <11%). We used this assay to measure pepsinogen C in seminal plas ma, breast cyst fluid, amniotic fluid, male and female serum, serum fr om patients with prostate cancer, urine, breast tumor cytosolic extrac ts, breast milk, and cerebrospinal fluid. Highest pepsinogen C concent rations were in seminal plasma, followed by breast cyst fluid and amni otic fluid. We found no correlation between prostate-specific antigen concentrations and concentrations of pepsinogen C in serum of prostate cancer patients, and concluded that this marker is not useful for eit her diagnosing or monitoring prostatic carcinoma. The availability of a highly sensitive, reliable, and convenient method for quantifying pe psinogen C will allow investigations into the possible diagnostic valu e of this analyte in various clinical conditions, including benign bre ast diseases, breast cancer, fertility, and pregnancy.