Fatty acid synthase is highly expressed in carcinoma, adenoma and in regenerative epithelium and intestinal metaplasia of the stomach

Aims: To investigate the relation of fatty acid synthase (FAS) expression to the clinicopathological characteristics of gastric cancers and gastric tumorigenesis. Methods and results: PAS expression was examined immunohistochemically in 626 gastric cancers, 51 gastric adenomas, and non-neoplastic epithelium 3 contiguous with cancer tissue including normal foveolae, intestinal metaplasia, regenerative epithelium, and gastric glands. PAS expression was found in more than 700 of gastric cancers. Interestingly, it occurred preferentially in differentiated carcinomas, male cases, and in patients over 51 years old. Although previous reports showed that PAS expression is closely related to cancer progression, in gastric cancers PAS expression had no relationship with prognosis, cancer progression as indicated by depth of invasion, venous and lymphatic permeation, and distant metastasis. Gastric tubular adenoma and intestinal metaplasia, which are thought to be associated with well-differentiated gastric carcinomas, showed a frequency of PAS expression similar to that of differentiated carcinomas; however, normal foveolae and gastric glands showed no or less PAS expression. Conclusions: PAS expression occurs at the early stage of tumorigenesis and plays important roles in the formation of precancerous foci rather than in the progression of carcinoma of the stomach.