Expression Of Let-7a-1 Precursor And K-ras In Esophageal Carcinoma And Its Significance

Background and ObjectiveEsophageal carcinoma(EC) is one of the most common turmors of digestive tract which does great harm to people's health in China,especially in Henan,Jiangsu,Shanxi provinces.Many molecules and facters take part in the multistage process of carcinogenesis of esophague,but what and how many genes take part in the complicated regulating networks is not clear right now.MicroRNA(miRNA) are a great amount category of 21-23 nucleotide small noncoding RNA molecules that were discovered existing in many organism of nature world and inhibit gene expression through sequence-specific translational repression and/or degradation of cognate mRNA.t had conformed that miRNA regulate and control many complicated biological procedures.Especially the low expression of let-7miRNA in human's lung,colon and some other turmors may indicates that let-7 participate in cancergene of tumors as an anti-oncogene.And let-7 protect from growth of some tuor by suppression of Ras and c-myc oncogene in human lung cancer.To understand the roles of miRNA in EC,in this study,we analyzed the expression of let-7 and K-ras in 20 EC specimens.The analysis may be helpful for perfection and development of the complicated gene regulatory network of EC.Also,it may discover let-7 as a new cancer biomaker that could be useful for diagnosis,therapeutics and prognosis in EC.Materials and MethodsTo investigate the expression of let-7a-1 precursor and K-ras in EC,we collected 20 sets of esophageal cancer samples at the first affiliated hospital of Zhengzhou University,including tumor tissues, their correspongding benign mucosa tissues and the basic clinical information of the patients. TRIzol was used to isolate the Total RNA according to the instructions of manufacturer. RT-PCR was used to semiquantify the expression levels of let-7a-1 precursor and K-ras. Statistical comparisons were done by SPSS 16.0 software to evaluate where differentially expression of let-7a-1 precursor and K-ras in various biopathologic features associated with tumor speciments and the internal relations in each other in EC.ResultsThe positive expression rate of let-7a-1l precursor and K-ras was significantly lower and upper (over 2-fold) in EC was 40%(8/20) and 35%(7/20) respectively. However, no significant statistical difference in K-ras expression was observed between tumors and normal tissues (P>0.05). Also, the biological and pathological characteristics did not have any significant difference in let-7a-1 precursor and K-ras expression levels and there was no significant correlation between let-7a-1 precursor and K-ras in EC (P>0.05)ConclusionsLow expression of let-7a-1 precursor in EC indicated that let-7a-1 might participate in the carcinogenesis of esophageal cancer as an anti-oncogene.Oncogene K-ras,may not the target of let-7a-l,is not important in the carcinogenesis of EC.