Regan isoenzyme in ovarian cancer: reappraisal with a new assay method.

A new assay method was designed to determine the Regan isoenzyme in sera of patients with ovarian carcinoma. An attempt was made to improve the specificity and sensitivity of the assay. Serum was heated at 65 degrees C for 2 hr to complete the inactivation of intestinal alkaline phosphatase, then incubated with 2'-AMP at 37 degrees C for 20 hr. Adenosine produced was then quantified by anion-exchange column chromatography. Seventy-nine percent of patients with ovarian carcinoma showed elevated activity of the Regan isoenzyme.