Correlation Study Of K-ras Gene Mutation, P53 Protein Expression And Pathobiological Characteristics In Colorectal Cancer

Background:The morbidity and mortality of colorectal cancer are increasing over the world. At present, the pathogenesis and development mechanism of the colorectal is still unclear. It was reported that the development and metastasis of colorectal cancer was in relationship with activation of some oncogenes and transcription silencing of anti-oncogenes, such as P53 gene, nm23 gene and VEGF. Especially, K-ras gene and P53 protein are playing important role in the progress of colorectal cancer. Both of their detection can be used for determining prognosis of colorectal cancer.Objective:To evaluate the correlation between K-ras gene mutation, P53 protein expression and pathobiological behavior of colorectal cancer for supplying theoretical support for further illustration on molecular mechanisms.Methods:78-case clinicopathological data which from colorectal cancer from Jan.2008 to Aug.2010 in our department were collected to set up the database. We tested K-ras gene mutation and P53 protein, then analyzed K-ras gene mutation rate and P53 protein expression. Then the associations between K-ras mutation status, P53 protein expression and pathobiological characteristics in colorectal cancer were analyzed.Results: (1) K-ras gene mutation:26 cases were detected mutation in 78 cases of colorectal cancer specimens. The mutation rate was 33.3%.19 cases of mutation occurred in codon 12.The mutation rate was 24.4%. The major mutation way is GGT→GAT (35.7%).7 cases occurred in codon 13. The mutation rate was 9%. The mutation way is totaly GGC→GAC (26.9%). K-ras gene is all single basic group point mutation. The major mutation way is G→A (76.9%).(2) P53 protein expression:62 cases were tested overexpression in 78 specimens. The expression rate was 79.5%. The positive expression rate was 24.2% (15/62). The moderately positive expression rate was 4.8% (3/62). And the strong positive expression rate was 71% (44/62).(3) K-ras mutation and its correlation with gender, age, location of primary tumor, tumor form, histology type of tumor, lymph node metastasis and hepatic metastasis:The frequency of k-ras mutation is no significant statistical difference with gender age, location of primary tumor, tumor form, lymph node metastasis (P>0.05). The frequency of k-ras mutation is significant statistical difference with histology type of tumor, and hepatic metastasis (P<0.05).(4) P53 protein expression and its correlation with gender, age, location of primary tumor, tumor form, histology type of tumor, lymph node metastasis and hepatic metastasis:The expression of P53 protein is no significant statistical difference with gender age, location of primary tumor, tumor form, histology type of tumor, lymph node metastasis (P>0.05). The expression of P53 protein is significant statistical difference with hepatic metastasis (P<0.05). Conclusion:(1) The experimental results showed:the k-ras gene and P53 protein are correlated with the occurrence of colorectal cancer.The rate of k-ras gene mutation in colorectal cancer in our department was 33.3%. The rate of P53 expression was 79.5%.(2) The mutations are mainly located in codon 12/13. The codon 12 mutation rate was 24.4%. The major mutation way is GGT→GAT (50%). The codon 13 mutation rate was 9%. The mutation way is totaly GGC→GAC (26.9%). K-ras gene is all single basic group point mutation. The major mutation way is G→A (76.9%).(3) K-ras gene mutation is correlated with histology type of tumor. K-ras gene mutation becomes more likely as the differentiation is more worse; And the K-ras gene mutation is also correlated with hepatic metastasis. The frequency of K-ras mutation is no correlated with gender, age, location of primary tumor, tumor form, and lymph node metastasis.(4) P53 protein expression is correlated with hepatic metastasis. P53 protein highexpression becomes more likely as hepatic metastasis. The expression of P53 protein is no correlated with gender, age, location of primary tumor, tumor form, histology type of tumor, and lymph node metastasis.