Tissue microarray analysis of multiple gene expression in intestinal metaplasia, dysplasia and carcinoma of the stomach.

Aims: To study multiple gene expression patterns and their roles in the process of gastric carcinogenesis.
Methods and Results: Using a high-throughput tissue microarray technique, 169 specimens from gastric carcinomas, precursor lesions and normal mucosa were immunostained on a series of tissue chips for p53, p21(WAF1/CIP1) cyclin E, Bcl-2, c-met and mucin 5AC expression. The overexpression of p53 was observed in 10.7% of low-grade dysplasia (LGD), 38.1% of high-grade dysplasia (HGD) and 39.6% of intestinal type gastric carcinoma (IGC). Expression of p21(WAF1/CIP1) was found in 47.6% of incomplete intestinal metaplasia (IM), 36.7% of dysplasia (Dys) and 29.5% of IGC. The overexpression of cyclin E was more frequently present in carcinomas than in Dys (P < 0.05); moreover, high-level expression (> 25% in extent) of cyclin E was observed only among IGC. Abnormal Bcl-2 expression was present in 81.0% of incomplete IM, 69.4% of Dys and 22.9% of IGC. Along with progression of the lesion, the expression of c-met increased; in contrast, mucin 5AC decreased gradually.
Conclusions: The specific expression pattern in incomplete IM was mucin 5AC+/Bcl-2+/p53-/cyclin E-, while mucin 5AC-/cyclin E+ was specific for IGC. p53 was useful for distinguishing LGD from HGD. High-level expression of cyclin E might be an indicator for malignant transformation of dysplasia.