[654] P53 Expression and Proliferation Index Measured by Ki-67 Immunostaining in Gastric Pit Dysplasia.

Arong Kim, Min-Kyung Park, Kyung-Bin Kim, Joo-Yeon Kim, Nari Shin, Kyung-Un Choi, Do Youn Park, Gregory Y Lauwers. Pusan National University Hospital and Pusan National University School of Medicine, Busan, Korea; Massachusetts General Hospital, Boston

Background: Despite the wide acceptance of the chronic gastritis-intestinal metaplasia-dysplasia-carcinoma sequence, especially for intestinal type gastric adenocarcinoma, the precise detailed biologic characteristics of gastric pit dysplasia as one of precursor lesions of gastric cancer remains to be delineated.
Design: We have evaluated the surrounding gastric mucosa of 414 gastric cancers for the presence of gastric pit dysplasia (GPD) (dysplasia in pit with surface foveolar maturation). We investigated the p53 expression, Ki-67 immunohistochemistry for proliferation index for the characterization of GPD lesions compared to normal appearing mucosa. For the measurement Ki-67 and p53 expression, we subdivided gastric mucosa into three portions; upper, middle and lower thirds. We evaluated Ki-67 and p53- positive cells by counting the number of positive cells at least at least total number of 200 epithelial cells counted in each portion of gastric mucosa.
Results: We have found 21.0% (n=87) cases of GPD in adjacent gastric mucosa out of 414 gastric adenocarcinomas. p53 expression was evident in lower portion of gastric epithelial cells compared to adjacent normal appearing mucosa. Proliferation index measured by Ki-67 immunostaining was higher in lower third in GPD compared to in middle third in adjacent mucosa.

Ki-67 labelling index and p53 expression in gastric pit dysplasia of 39 cases of gastric adenocarcinoma
 P53 positive cells (%)Ki-67 positive cells (%
 Gastric pit dysplasiaAdjacent gastric mucosaGastric pit dysplasiaAdjacent gastric mucosa
Upper0.54±0.100.07±0.041.26±0.151.41±0.17
Middle*2.05±0.250.13±0.074.00±0.3412.85±0.93
Lower*8.23±1.060.20±0.1314.59±0.923.00±0.23
Data means means±standard errors and % of positive cells at least 200 gastric epithelial cells counted. * means p<0.05.


Conclusions: We suggest that gastric pit dysplasia is neoplastic and important candidate precursor of gastric adenocarcinoma and may represent another pathway for the pathogenesis of gastric adenocarcinoma, especially of intestinal type.
Category: Gastrointestinal

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 146, Tuesday Morning

 

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