Significance Of The Expression Of P53 Protein And Ki-67 Antigen In Appendiceal Mucinous Neoplasms And Pseudomyxoma Peritonei

Background and ObjectiveAppendiceal mucinous neoplasm is the main type of primary appendicealneoplasms. Tumors spread through inner wall of appendix to replace normal mucosa with the columnlike cells which excrete a great number of grume and differentiate well with different grades of atypia. Part of the cells can form sacculation structure. According to whether having infiltrate muscular layer or not, appendiceal mucinous neoplasms usually are divided into mucinous adenoma and mucinous adenocarcinoma. Appendiceal mucinous neoplasm has a particular clinical character. Its remedy and prognosis obviously differ from familiar colorectal cancer and adenocarcinoma of appendix. Pseudomyxoma peritonei syndrome (PMP) is one special pathological change which results from mucinous neoplasms invade peritoneal surface and involves organs in abdominal and pelvic cavity. It is presently recognized that pseudomyxoma peritonei syndrome is arised from appendiceal mucinous neoplasm.This study was to detect the expression of p53 protein and Ki-67 antigen in appendiceal mucinous neoplasms and pseudomyxoma peritonei, to investigate the relation between the expression of the foregoing ones and clinical characters of appendiceal mucinous neoplasms, and the significance of the foregoing ones in the occurrence and development of appendiceal mucinous neoplasms.Materials and MethodsA total of 42 samples of appendiceal mucinous neoplasms were selected by pathological diagnosis in the department of pathology of the PLA general hospital in the years from May, 1993 to October 2007, 30 of which were diagnosed as appendiceal mucinous adenocareinoma, 12 of which were diagnosed appendiceal mucinous adenoma. The 10 samples of comparison were obtained from simple appendicitis after surgery. By using immunohistochemical methods of PV6000, we detected the expression of p53 protein and Ki-67 antigen in appendiceal mucinous neoplasms and simple appendicitis respectively.ResultsThe positive rate of p53 protein and Ki-67 antigen were 31.0% and 45.2% in appendiceal mucinous neoplasms tissue, 40.0% and 53.3% in appendiceal mucinous adenocareinoma tissue, and 8.3% and 25% in appendiceal mucinous adenoma tissue respectively. The positive rate of the forgoing ones were 0% and 10.0% in appendicitis tissue comparatively. By comparison, the expressions of the foregoing ones in appendiceal mucinous neoplasms were all higher than those in appendicitis tissue. There were significant difference (P<0.05). The positive rate of p53 protein in appendiceal mucinous adenocareinoma was higher than that in appendiceal mucinous adenoma tissue (P<0.05). The significant difference was not noted between the expression of Ki-67 antigen in mucinous adenocareinoma and mucinous adenoma tissue.The positive rate of p53 protein was 45.5% in appendiceal mucinous neoplasms tissue with pseudomyxoma peritonei which was higher than that in tissue without PMP (15.0%) (P=0.033). The positive rates of Ki-67 antigen between the foregoing two tissues were not significantly different (P>0.05).In appendiceal mucinous neoplasms the positive rates of Ki-67 in the positive expression group of p53 protein and in the negative group were 76.9% and 31.0% (P=0.0057). Obviously the correlation was found between the expression of p53 protein and Ki-67 antigen. ConclusionsThe results showed that mutation of p53 gene play a significant role in the occurrence and development of appendiceal mucinous neoplasms and related to tumor's malignant transformation. The expression of Ki-67 antigen was found to have some relation to proliferation activity in appendiceal mucinous neoplasms, but was not one reliable index to detect the malignant degree. The expression of p53 protein was related with the expression of Ki-67 antigen. In the positive expression of p53 protein tissue, the proliferation activity of tumor cells was obviously higher. It's valuable that both p53 protein and Ki-67 antigen be used to evaluate the biological behavior of appendiceal mucinous neoplasms and predict the malignant degree.