The Expression And The Clinical Significance Of RAD9Gene In Human Colorectal Cancer By FQ-PCR

Objective:Colorectal cancer is one of the common gastrointestinalneoplasms,and its incidence rate is third leading in the global malignanttumors, fourth in China. Recently, with the development of the living standardof the people, and with the changes of dietary pattern and population aging,the incidence of colorectal cancer is gradually increasing. At present, the exactcause of colorectal cancer is not yet entirely clear.With the rapid developmentof molecular biology,it is generally accepted that colorectal cancer is multiplefactors and multi-stage complicated process, and the etiology of colorectalcancer is result of environmental and genetic factors, involving in thecumulative changes of many gene, for example, the activation of oncogenesand the mutations and inactivation of anti-oncogenes and mismatch repairgenes, especially the inactivation of anti-oncogenes plays an important role intumorigenesis.The RAD9gene was found firstly in fission yeast mutants, and it isan evolutionarily highly conserved gene. RAD9gene is an importantmember of DNA damage response system. This system is responsible forthe dealing with a variety of DNA damage and maintaining genomicstability. The RAD9gene plays a crucial role in controlling cell cyclecheckpoint, DNA damage repair and induction of apoptosis,which helpto maintain genomic stability and inhibit tumor cell proliferation.Therefore, the RAD9gene acts as anti-oncogene in tumor development.For example, studies have shown that the down-regulation of RAD9geneexpression was associated with some human cancer, such as skin cancer,gastric cancer.To explore the role of the RAD9gene in colorectal cancer,we investigated the expression level of RAD9mRNA in colorectal cancertissues and matched para-cancer tissues by using real-time flurecence quantitive PCR,combined with the pathological characteristics,whichdetermine the relationship between the expression of RAD9gene andprogression of colorectal cancer, and it may provide theoretical foundation forthe study of colorectal development and its clinical diagnosis and treatment.Method:We selected colorectal cancer tissue and matched para-cancer tissues (10cm from the border)from42patients with colorectal cancer. RAD9mRNAexpression level of human colorectal cancer tissue and matched para-cancertissues were detected by using real-time fluorescence quantitative PCR,GAPDH is designed as reference standard,and we comparativly observedexpression difference of colorectal cancer and normal tissues, combined withthe Ministry of Health colorectal cancer diagnostic and treatment standard(2010), and the experimental data were stratifiedly analyzed according to theclinical and pathological characteristics. We used the SPSS13statisticalsoftware to analyze the data, the difference was considered as significance if P<0.05.Results:1The different expression levels of RAD9mRNA were detected incolorectal cancer tissues and matched para-cancer tissues, and the expressionlevel of RAD9mRNA in85.71%(36/42) colorectal cancer tissues lower thanthe matched para-cancer tissues. After data conversion, the expression level ofRAD9mRNA in colorectal cancer tissues (0.65±1.12) is lower than that inpara-cancer tissues(4.93±7.99), the difference was statically significant (P<0.05).2The expression level of RAD9mRNA is not correlated with patients'gender, age, tumor size and tumor location, the difference was staticallysignificant (P>0.05).3The expression level of RAD9mRNA in colorectal cancer tissues withmetastasis of lymph node (0.30±0.51) lower than that without metastasis oflymph node (0.97±1.40), the difference was statically significant (P <0.05).4The expression level of RAD9mRNA in colorectal cancer tissues of stage Ⅲ+IV(0.30±0.49) lower than that the stage Ⅰ+II(1.01±1.43), thedifference was statically significant (P <0.05).5With the decline in the degree of differentiation,the expression level ofRAD9mRNA colorectal cancer tissues is decreasing, and there is a staticallysignificant difference among the group of different degree of differentiation(P<0.05), the expression level of RAD9mRNA in higher differentiation group(1.21±0.65) higher than that in lower differentiation group (0.19±0.11)(P<0.05), the expression level of RAD9mRNA in higher differentiation group(1.21±0.65) higher than that in middle differentiation group (0.73±0.97)(P<0.05),the difference between middle differentiation colorectal cancer group(0.73±0.97) and lower differentiation colorectal cancer group (0.19±0.11) isnot statistically significant (P>0.05).Conclusion:1The expression levels of RAD9mRNA in colorectal cancer tissueslower than that in para-cancer tissues, which suggested that expression level ofthe RAD9gene may be related to colorectal cancer development, the lowerexpression level of RAD9gene may lead to genomic instability and inhibitapoptosis of tumor cells, which promoted colorectal cancer progression.2The expression level of RAD9mRNA is not correlated with patients'gender, age, tumor size, tumor location.3With the metastasis of lymph node,the increase in stage and the declinein the degree of differentiation, which suggested that the expression level ofRAD9mRNA in colorectal cancer tissues are closely related to aggressivenessand transferability of colorectal cancer and the prognosis of patients.