Tenascin expression in inflammatory, dysplastic and neoplastic lesions of the human stomach.

We studied the expression of tenascin (Tn) in human stomach. In the normal mucosa of the antrum and body, Tn reaction was only seen in the muscularis mucosae, in the region of the pyloric sphincter and in the duodenum, a Tn-immunoreactive rim was seen underlying surface epithelial cells. Antral gastritis, irrespective of the degree of inflammation, showed a rim-like Tn expression under the surface epithelial cells but no Tn reaction was seen in mild chronic gastritis of the body. In some moderate and severe examples of chronic gastritis a delicate Tn-reactive line was seen to underline the surface epithelium focally and the neck regions of gastric pits. Discontinuous Tn immunoreactivity was sometimes seen beneath hyperplastic epithelium in both parts of the stomach. A Tn-immunoreactive line was seldom seen surrounding glands showing intestinal metaplasia. In both benign and malignant ulcers prominent Tn immunoreaction was seen at the base of ulcers extending deep into the underlying muscularis. Only severely dysplastic lesions displayed Tn in the lamina propria, in close association with capillaries. In early forms of diffuse gastric cancer (DGCA) raggedly increased Tn staining was seen in the lamina propria underlying affected surface epithelial cells. In advanced forms of DGCA consistent Tn expression was seen in the tumour stroma. A distinct Tn reaction was seen surrounding invasive tumour cell nests of intestinal type gastric cancer (IGCA) in the submucosa, whereas in early forms of the tumour enhanced Tn reaction was noted predominantly in the upper part of the lamina propria in the vicinity of dysplastic elements. Notably, while most invading DGCA tumour cell nests showed no Tn in the submucosa and muscle cell layer, invading IGCA islets showed prominent expression of Tn. The most conspicuous Tn enhancement in the stomach is seen in invasive tumours and in ulcers suggesting that Tn is an important stromal component in malignant growth and in lesions undergoing active repair and remodelling.