Regan isoenzyme: a carcinoplacental antigen.

Abstract

Summary The Regan isoenzyme3 of alkaline phosphatase of human cancer tissue first described in this journal (9) is a carcinoplacental antigen. The experimental evidence shows lines of identity between alkaline phosphatase antigens of placental and tumor tissue origin and corresponding rabbit antisera to these antigens. Also, the loss in the enzyme activity of the antigen in both antigen-antibody complexes is identical within the limits of experimental error as a function of dilution of antiserum. The reasons for considering Regan isoenzyme antigen carcinoplacental as opposed to fetal are presented.