The Expression Of P53, PCNA, EGFR And Its Relationship To Clinicopathological Features And Prognosis Of Gastric Cancer

Background and objective:Gastric cancer is the second most frequency cancer in the world, the mortality rate of which is the highest in China. The prognosis of gastric cancer is influenced by mangy factors, with clinical stage, lymph node metastasis and the depth of invasion as the most important factors. There are limitations to understand biological behavior of gastric cancer simply based on morphologic characters. The development of molecular biology implies that the morphologic feature and biological behavior of gastric cancer are the result influenced by many oncogenes and tumor suppressor genes."Wild p53 gene is a tumor suppressor gene, regulating the growth and apoptosis the cell. Mutation, deletion and dysfunction of p53 gene exist widely in various humor tumors. Researches showed p53 protein was over-expressed in many malignancies such as breast cancer, lungcancer and bladder cancer. Proliferating cell nuclear antigen (PCNA) is a nuclear protein with a molecular weight of 36KD, with a close relationship to DNA replication and cellular proliferation, can be used as an indicator for the malignant degree and prognosis of tumors. Epidermal growth factor receptor (EGFR) is the product of proto-oncogene c-erbB-1, and is over-expressed in many tumors, including gastrointestinal tumor and brain tumor.In this study, immunohistochemistry method was used to detect the expression of p53, PCNA and EGFR in 78 cases of gastric cancer, the relationship between the expression of these three proteins and the invasion, metastasis and prognosis of gastric cancer was analyzed. The aim of this study was to investigate the impact of p53, PCNA and EGFR on the development of gastric cancer, and its role for the judgment of the prognosis of gastric cancer. Method:Surgically resected and pathologically proved cases of gastric cancer were collected. These patients have been followed up for 5 years by questionnaire and phone calls, 78 cases with complete clinical and follow-up information were included in this study, all the patients received neither radiocherapy nor chemocherapy before the surgery. Information related to patient's sex, age, tumor location, histological type, pathological stage, surgery approach and survival time wererecorded. All the paraffin-embedded tissues of 78 cases were serial sectioned with a thickness of 4μm. The specimen cases were immunostained to observe the expression of p53, PCNA and EGFR in gastric cancers cells. All the results were statistically analyzed with SPSS 12.0 software package. Result:Positive expression of p53 protein was found in 69.2% (54/78 cases) gastric cancers, its expression was related to distant metastasis of gastric cancer (p<0.05); while with no relation to patient's sex, age, tumor size, differentiate degree, the depth of invasion, lymph node metastasis (p>0.05) .Strong positive expression of PCNA protein was found in 21.8%(17/78 cases) of gastric cancer, its expression was related to thedifferentiation degree and metastasis of gastric cancer (p<0.05) , whilewith no relation to the patient's sex, age, tumor size, invasion degree,lymph node metastasis (p>0.05) .Positive expression of EGFR protein was found in 41.0% (32/78 cases) of gastric cancer, the expression of EGFR protein was related to the differentiation degree, the depth of invasion, lymph node metastasis and distant metastasis of gastric cancer (p<0.05 ) , while with no relation to the patient's sex, age and tumor size (p>0.05 ) .Cases with positive expression of p53,PCNA and EGFR, 3-yearsurvival period and 5-year survival period were decreased obviously (p<0.05) .Positive correlation of PCNA and EGFR was found (p<0.05) , but no relation was found between p53 and EGFR, p53 and PCNA(p>0.05). Conclusion:1. The expression of p53 protein in gastric cancer was related to the distant metastasis of gastric cancer.2. The expression of PCNA protein in gastric cancer was related to the differentiation degree and distant metastasis of gastric cancer.3. The expression of EGFR protein in gastric cancer was related to the differentiation degree, the depth of invasion, lymph node metastasis and distant metastasis of gastric cancer.4. The expression of p53, EGFR and PCNA negatively correlated to the prognosis of gastric cancer.5. The expression of PCNA in gastric cancer positively correlated to that of EGFR.6. Detection of the expression of p53, PCNA and EGFR simultaneously may be helpful for directing treatment and assessing the prognosis of the patient with gastric cancer...