The histoenzymatic activity of numerous hydrolytic and oxidative enzymes was determined in cryostat sections of fresh tissues obtained surgically from 15 patients with gastric carcinoma, 18 normal subjects, and 28 patients with chronic atrophic gastritis and intestinal metaplasia. T h e average enzyme activity in malignant cells was less than that found i n intestinal metaplasia but greater than that found in nonnal gastric surface epithelium. Stromal inflammatory cells exhibited activity for acid phosphatase and B-glucuronidase, and smooth muscle fibers stained for the lactic and succinic dehydrogenases and DPN and T P N diaphorases. These elements and the islands of intestinal metaplasia found in malignancy-bearing stomachs may contribute to the elevated levels of certain enzymes found biochemically in gastric secretions and tissue homogenates from patients with gastric carcinoma. Lactic dehydrogenase and the diaphorases were found in many carcinomata whereas succinic dehydrogenase was found in only one case. This pattern may be related to the high glycolytic rate cbaracteristic of most malignant tumors, including those arising in the stomach.
T HAS BEEN STATED THAT ELEVATED LEVELS OF I certain enzymes in the gastric juice may be of value in the diagnosis of primary gastric carcinoma.17t 27.42 Sources other than the malignant tissue itself, however, such as stro-ma1 elements or islands of intestinal metaplasia, might have contributed to such increased enzyme levels. As to the enzyme assay in homogenates of cancer tissue, tissues used as normal controls must be defined histologically since the enzyme histochemistry of the fundic and pyloric mucosa differs5 and homogenates from those areas may reflect these differences.