Exploring P16 protein expression in gastric carcinoma and its precancerous lesions

Objective:To explore the P16 protein expression in primary gastric cancer and its pathological changes in order to find out the role in the progress of stomach carcinogenesis . Methods:Specimens from 43 normal gastric mucosa cases, 35 from intestinal metaplasia, 50 from gastric dysplasia, and 40 fresh tumor specimens were collected for this study. The expression of P16 protein in gastric mucosa in each phrase from normal ones to precancerous lesions resulting in gastric cancer were detected by immunohistochemical method (IHC). Results:Positive rate of P16 protein expression suggested a percentage of 86% in normal gastric mucosa cases, 69% in intestinal metaplasia, but 83%, 71% and 35% stood for mild, moderate and severe gastric dysplasia cases respectively. It was seen in gastric cancer with a percentage of 23%(intestinal type, 29% and diffuse type, 19%). The positive rate of P16 protein showed no significant difference among normal gastric mucosa, mild and moderate dysplasia, and the intestinal metaplasia (P0.05). No difference demonstrated between severe dysplasia and gastric cancer (P0.05), but there was between the positive rate of P16 protein in each former group (P0.05). Conclusion:The abnormality of P16 protein expression occurred in early stages and tends to increase with the multi-step gastric carcinogenesis.