Study For Expression And Relationship Of Pokemon Gene And P14～(ARF),p53 Protein In Human Colorectal Cancer

Background and objective:Colorectal cancer was considered a genetic disease would happen if there were defects in genes that would control cell differentiation. Recently in vitro study and animal experiments have show oncogene Pokemon could inhibit suppress gene ARF in specificity. Pokemon plays an important role in occurrence and development of tumor. P14ARF was encoded from INK4a-ARF, a cancer suppress gene. P14ARF could postpone the degradation of p53. The p53 is regulated by p14ARF in cell cycle regulation. P53 is a cancer suppress gene. It could transit stimulating information from outside of cell into gene, which could prevent cell from G1 to S phase and induce apoptosis. P53 is mutated in colorectal cancer and can be detected by immunohistochemical method. At present, researches about the relationship of p14ARF,p53 and colorectal cancer are more than Pokemon which can develop cancer through ARF-p53 pathway. The colorectaI cancer samples we collected were different in their pathological levels. In our study, the expression of Pokemon mRNA was detected by semi-quantitation RT-PCR and the expression of p14ARF and p53 protein was investigated by immunohistochemical test. We also analyze the relationship of the expression of Pokemon and the expression of p14ARF and p53 at the same time. We expected our study could provide molecular biology evidence of potential mechanism in occurrence, progressing of colorectal cancer.Methods:Thirty-nine cases with colorectal adenocarcinoma were included in the present study who were performed surgical resection in Tongji University affiliated Tenth Shanghai municipal Hospital April, 2005 to December, 2005. Those recurring colorectal cancers after operation and with primary malignant tumors of other organs were excluded. All cases did not take radiotherapy and/or chemotherapy before. The expression of Pokemon mRNA in cancer and para-cancer tissues was detected by semi-quantitation RT-PCR test. Pathological staging and histological grouping were identified by routine HE dying. The expression and distribution of p14ARF and p53 were investigated using immunohistochemical dying of SP method. For all statistical analysis, SPSS 10.0 software was used. The probability of less than 0.05 was assumed to be statistically significant (P＜0.05).Result:RT-PCR result: The result of RT-PCR showed that the expression of Pokemon mRNA was found both in colorectal cancer and para-cancer samples. The expression of Pokemon mRNA in colorectal cancer samples was higher than in para-cancer samples. The difference was significant in statistics. The expression amount was related with cancer differentiation.Immunohistochemistry result: The result of immunohistochemical dying showed that the expression of p14ARF and p53 protein was found both in colorectal cancer and para-cancer samples. The expression of p14ARF in colorectal cancer samples was lower than in para-cancer samples and the expression of p53 in colorectal cancer samples was higher than in para-cancer samples. The difference was significant in statistics. Expression of p14ARF and p53 was not related to differentiation degrees.Conclusion:1. The expression of Pokemon mRNA in colorectal cancer samples was higher than in para-cancer samples. This suggested that Pokemon gene expression is involved in colorectal cancer. The expression amount was related with cancer differentiation. This suggested that Pokemon gene expression maybe related with malignancy degree.2. The expression of Pokemon mRNA was negatively related with the expression of p14ARF both in colorectal cancer and para-cancer samples. This indicated the mechanism of Pokemon maybe through inhibiting ARF protein.3. The expression of Pokemon mRNA was not related with the expression of p53 both in colorectal cancer and para-cancer samples. This supposed Pokemon did not inhibit p53 directly. But it could not confirm Pokemon has no effect in p53 pathway.