Study on expression of Cyclin D_1 protein and p16 protein in human gastric cancers

Objectives:To explore the correlation of Cyclin D 1 and p16 protein expression with carcinogenesis and biologic behavior of gastric cancers. Methods:The expression of Cyclin D 1 and p16 protein in human gastric cancers and normal gastric tissues was studied immunohistochemically on 70 paraffin embeded gastric cancer tissues.PCNA LI was used to analyze the correlation between the expression of the two proteins and the prognosis of human gastric cancers. Results:①Cyclin D 1 protein positive staining was seen in 47 cancers(67.1%),whereas no Cyclin D 1 expression was found in normal tissues( P 0.01).The percentage of positive Cyclin D 1 in well differentiated carcinomas(42.3%) was lower than that in poorly differentiated carcinomas( 80.6 %)( P 0.01), and lower than that in undifferentiated group (87.5%)( P 0.05).②The expression level of p16 protein was very significantly lower in cancer tissues(40%) when compared to that in their normal counterparts(65.7%)( P 0.01).As the cancer differentiated from well to poorly the cells immunostaining p16 positive decreased very significantly in number( P 0.01).③The expression of Cyclin D 1 and p16 are adversely correlated( P 0.01).All subjects were divided into two groups by mean PCNA LI(60.9%). In the group in which PCNA LI 60.9 %,the expression of Cyclin D 1 was higher than that in the other group( P 0.01).For p16,the expression was higher in the group in which PCNA LI60.9( P 0.01). Conclusions:These findings suggested that the expression of Cyclin D 1 and p16 contribute to the oncogenesis,differentiation and may be related to the prognosis in human gastric cancers.And the expression of Cyclin D 1 and p16 are adversely correlated.