Alkaline phosphatase isoenzymes in detection and follow up of breast cancer metastases.

Alkaline phosphatase isoenzymes in bone and liver metastases of breast cancer were determined in 637 patients and during follow up in 116 patients, by agarose gel electrophoresis. The activity of total alkaline phosphatase, gamma glutamyl transferase, CEA and CA 15-3 was also determined. The sensitivity of bone alkaline phosphatase in bone metastases detection was 39%, of electrophoresis (total alkaline phosphatase and specific isoenzymes) 48% and of enzymes and tumor markers together 85% (n = 62). For liver metastases gamma glutamyl transferase had the best sensitivity (100%, n = 19). Even though positive predictive value was only 6%, the sensitivity of liver alkaline phosphatase was 58% and of electrophoresis 94%. The determination of alkaline phosphatase isoenzymes is a non-invasive, in-expensive, reproductable and rapid method to detect progressive disease in breast cancer, especially in combination with the tumor markers CA 15-3 and CEA.