| Research Abstract |
1)At first, glands from the non-neoplastic pyloric mucosa in 50 advanced gastric cancer cases were isolated. Then, they were divided into a single gland according to the gastric, gastric and intestinal mixed-and intestinal types, respectively. We tried to extract DNA from it and analyze the replication error for the amplified DNA using several microsatellite markers, but could not, probably because of insufficiency of good and enough DNA.
2)For 70 advanced gastric cancer cases, immunohistochemical analyses of phenotypic expression and expression of hMLH1 gene in carcinoma cells were done using formalin-fixed, paraffin embedded sections. Seventeen cases showed decreased hMLH1 gene expression. They included 4 gastric, 2 gastric and intestinal mixed-, 6 intestinal, and 5 unclassified types, respectively. Consequently, no apparent correlation was identified between the phenotypic expression of cancer cells and genomic instability.
3)For above cases, the expression of hMLH1 gene was also immunohistochemically investigated both in the normal and in the intestinal metaplastic mucosa surrounding the tumors. In a few cases, it was mildly decreased in the intestinal metaplastic epithelium of gastric and intestinal mixed-type, but no decrease was found in the normal epithelium.
4)Considering the result of 3), further analyses for RER were not performed both in the intestinal metaplastic and in the normal epithelium using the microdissection method.
5)The RER analyses for gastric cancer cells in 20 advanced cases revealed no apparent correlation among the phenotypic expression, microsatellite instability, and immunohistochemical expression of hMLH1 gene.
6)The above results could not clarify the interrelationship between genomic instability and cellular differentiation disorders of intestinal metaplastic cells or cellular differentiation status of gastric cancer cells.
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