[Biochemical studies on alkaline phosphatase isoenzyme profile in endometrial cancer]

Heat-stable ALP has been attracting attention as one of the oncodevelopmental proteins. ALP are now subdivided by biochemical methods into three major groups e.g. tissue-unspecific, intestinal and term placental isoenzymes. Furthermore, term placental ALP in cancer is classified into L-leucine insensitive-Regan and L-leucine sensitive-Nagao isoenzymes. In this paper, we report ALP isoenzyme profiles of normal endometrium and endometrial cancers. 21 cases of normal endometrium and 11 cases of endometrial cancer were examined, and the ALP activity of their butanol extracts was measured by Fishman's method. To identify the ALP isoenzyme pattern, biochemical methods such as 65 degrees C heat-treatment and amino acid inhibition tests were carried out. Most of the ALP in both normal endometrium and endometrial cancers showed biochemical characteristics of tissue-unspecific ALP isoenzyme. A very small amount of term placental isoenzyme was found in normal endometrium. In endometrial cancers, term placental isoenzyme was often found at a higher level than in normal endometrium. Nagao isoenzyme was also found to emerge in a few endometrial cancer cases. From these data it was suggested that the ALP isoenzyme of endometrium underwent a change and "enzyme deviation" occurred during the course of endometrial carcinogenesis and that the ALP isoenzyme deviation might have occurred due to a change in ALP isoenzyme gene expression accompanying cancerous change.