The prevalence of variant alkaline phosphatase in hepatocellular carcinoma in southern African blacks

The prevalence of variant alkaline phosphatase in the serum of 335 southern African blacks with hepatocellular carcinoma was determined using polyacrylamide gel electrophoresis. The isoenzyme was detected in 2% (seven of 335) of the patients: it could not be found in the serum of 300 matched, healthy individuals or in 56 patients with various benign hepatic diseases. Variant alkaline phosphatase is thus of little use as a diagnostic marker of hepatocellular carcinoma in southern African blacks. The reported prevalence of this isoenzyme in hepatocellular carcinoma ranges between 3% and 31%. Higher frequencies usually are recorded in populations with a low incidence of the tumor, and the lowest frequencies have been found in Chinese patients. Our finding of variant alkaline phosphatase in only 2% of another high incidence population fits this trend. Patients with tumors that secreted the variant isoenzyme had a significantly higher serum total alkaline phosphatase activity than those with tumors lacking this property.