Expression And Significance Of P16, CyclinD1 And PCNA Protein In Pancreatic Endocrine Tumors

Objective To evaluate the expression and significance of P16, cyclinDIand PCNA protein in pancreatic endocrine tumors. Methods SPimmunohistochemical staining was performed to detect the expression of P16, cyclinDI and PCNA protein in 32 cases of pancreatic endocrine tumors and15 cases of normal pancreas. Results There were expressions of P16 andcyclinDI in different degrees in normal pancreas and pancreatic endocrine tumors. The positive reaction of P16 was located in the nuclei and cytoplasm. The positive rate of P16 in normal pancreas was 86. 7%, and 28. l%in pancreatic endocrine tumors. The former was highly significantly higher than the latter (x2=14.06, P<0.01). No significance was found in the expression of P16 between benign and malignant tumors or functioning and nonfunctioning tumors(P>0.05). The positive reaction of cyclinDI was mainly located in the cytoplasm, and a small number of nuclei were also stained. Of 32 cases of pancreatic endocrine tumors, there were 18 cases which had overexpression of cyclinDI (++~+++), and the overexpressive rate was 56.3%. While no overexpression of cyclinDI was found in normal pancreas. There was high significance between them(x2=13.67, P<0.01). No significance was found in the overexpression of benign and malignant tumors or functioning and nonfunctioning tumors(P>0.05). The positive reaction of PCNA was located in the tumor nuclei. The mean PCNA labeling index(PCNA LI) of malignant pancreatic endocrine tumors was significantly higher than that of benign pancreatic endocrine tumors (t=3.074, P<0.01). No significance was found in the mean PCNA LI of functioning and nonfunctioning tumors (P>0.05). Of 23 cases of pancreatic endocrine tumors which had positive expression of cyclinDI, there were 20 cases which had negative expression of P16. Whereas six cases of pancreatic endocrine tumors were positive expression of P163in nine cases of pancreatic endocrine tumors with negative expression of cyclinDl. There was a negative correlation between the expression of cyclinDl and P16(x2=8.91, P<0.01). PCNA LI of pancreatic endocrine tumors which had overexpression of cyclinDl was significantly higher than that of pancreatic endocrine tumors which had negative or low expression of cyclinDl (t=2.940, P<0.01). No significance was found in the PCNA LI of pancreatic endocrine tumors with positive and negative expression of P16(P>0.05). Conclusions The deletion of P16 and overexpression of cyclinDlplay important roles in the tumorigenesis and development of pancreatic endocrine tumors. Furthermore, there may be cooperation with them. The high expression of PCNA and overexpression of cyclinDl correlate with the malignant transformation of pancreatic endocrine tumors. The joint examination of PCNA and cyclinDl can assess the transformation of pancreatic endocrine tumors.Postgraduate: Zhao Dahua(Department of Pathology)Directed by ' Li Yujun...