Analysis of abnormal alkaline phosphatase in patient with high alkaline phosphatasemia

: We describe here a 69-year-old male with high serum alkaline phosphatase (ALP) activity who was showed high alkaline phosphatasemia. High ALP level, 112.4 K.A. was found in his serum. But, except for ALP, all other laboratory data including cancer markers were within normal range in this case. An electrophoretic pattern of patient ALP isozyme without neuroaminidase digestion showed liver-type ALP, but the ALP isozyme pattern with neuraminidase digestion from Vibrio Cholerae was identified as bone-type ALP. Moreover, the patient ALP reacted with anti-bone ALP MoAb. The apparent molecular size of patient ALP was 160kDa similar to bone ALP. Furthermore, we investigated the multiformity of the sugar chain(s) of patient ALP by serious lectin affinity chromatographies. From these results, the increase of multiantennary complex type and/or bisecting GlcNAc type sugar chain(s) of ALP was shown in patient serum. These results suggested that the patient might have a distant metastasis as in a case of carcinoembryonic antigen described previously. Besides, patient urinary pyridinoline and deoxypyridinoline was high level comparing normal adult urine. From detailed bone survey, the patient was observed the bone metastasis of cancer. Thus, the measurement of ALP sugar chain subfractions may be useful for diagnosis of patient with bone metastasis of cancer.