[Carcinoplacental alkaline phosphatase isoenzymes in malignant neoplasms]

A screening method for carcinoplacental alkaline phosphatase (CPAP) has been developed on the following principle: following the inactivation at 56 degrees C for sixty minutes, the sera with a residual activity are incubated in the presence of 5 mM L-phenylalanine. In case of L-phenylalanine inactivation by more than 60 per cent the serum is considered CPAP positive. Of 184 cancer patients 28 or 15.2 per cent were CPAP positive in the following order of malignancies: colon (46%), ovary (33%), liver (30%), stomach (16%), rectum (11%) and lungs (5.6%). By additional inhibition with 1 mM EDTA and acrylamide electrophoresis the "variant" of AP Regan was disclosed in two patients with primary and secondary cancer of the liver, respectively.