Evaluation of a human pancreas-specific antigen by enzyme-linked immunosorbent assay.

A sensitive sandwich-type enzyme immunosorbent assay has been developed for quantitation of a new human pancreas-specific antigen (PaA). With this method, PaA at a concentration as low as 0.8 ng/ml can be detected. The assay was reproducible as shown by the coefficients of variation for within (4.8%) and between (6.1%) assays. Serum PaA levels from 51 healthy persons ranged from less than 4 to 34 ng/ml. Using 21.5 ng/ml (the upper 97.5 percentile of normal controls) as an upper limit, 42 of 60 pancreatic cancer (70%), 3 of 14 pancreatitis (21%) and 2 of 6 cholelithiasis (33%) had an elevated PaA. Very few patients with other cancers were shown to have an elevated PaA: 3/40 (8%) of lung cancer, 2/43 (5%) of colorectal cancer, 3/40 (8%) of prostate cancer and 1/39 (3%) of breast cancer. The sensitivity and specificity of the serum PaA test for the detection of pancreatic cancer were calculated to be 70% and 95%, respectively. These results indicate that PaA may be useful as an adjunctive tool in immunodiagnosis of pancreatic cancer.