The Study Of APC Gene Mutations In Sporadic Colorectal Cancers In Ning Xia

Objective To investigate mutations of APC gene in sporadic colorectal carcinomas ofNing Xia through The digital protein truncation test labeled with fluorescent Lys-t-RNA,DHPLC and direct sequencing, analysis its use and its correlation with parameters of clinicalpatholog, evaluate the feasibility of Non-radioactive protein truncation test （nrPTT） onDetection of translation-terminating mutations of APC gene, provide theoretical basis ofdiagnosis and treatment for early colorectal carcinoma.Method （1）150patients with colorectal cancer were selected at Ningxia medicaluniversity general hospital, The patients had no family history of any type of cancer, Theinformation of relevant clinical was collected.（2） APC exon1-14was investigated withDHPLC, the samples showing mutation were thereafter sequenced. APC exon15wasinvestigated with The digital protein truncation test labeled with fluorescent Lys-t-RNA fromcancer tissue from50sporadic colorectal cancers patients, the samples showing mutationwere thereafter sequenced. APC exon15was investigated with direct sequenceing fromcancer tissue from100sporadic colorectal cancers patients.（3）Comparison of differentgroups was analysised by Chi-Square Test with the SPSS l8.0statistics software. Differenceswere considered significant when the p value was less than0.05.Result （1） Through the DHPLC and direct sequenceing, Tirty-four of the100（34%）colorectal carcinom showed mutations, including two novel sequence variants（c.3374T>Cp.Val1125Ala, c.3811T>G p.Phe1271Val）,27of35（77.1%） mutations resulted in truncationof the APC protein, Nosense is the main mutations mutations（21/27）.（2） Thirty of the50（30%） colorectal carcinom showed truncating mutations. The mutation type of five sanples is Nonsense mutation（c.4099C>T, c.3925G>T, c.1450C>T, c.2976₂977insT）, which resultin a truncated gene Product.（3） No significant correlation was found between the frequencyof APC mutation and clinical pathological parameters of colorectal carcinomas （P﹥0.05）.（4）There was no significant difference in the detection rates of truncating mutation between Thedigital protein truncation test labeled with fluorescent Lys-t-RNA and direct sequencing（X²=0.083, P﹥0.05）, The nrPTT is raid and high-efficient.Conclusion （1） The mutations of APC gene are common alterations in sporadiccolorectal carcinoma in Ning Xia, and has regional characteristic; Truncating mutations ofAPC gene are the main pattern in sporadic colorectal carcinoma.（2） This paper also showedthat after adenoma to carcinoma, mutation of APC gene doesn’t influence the progression ofcarcinomas. The mutations in the APC gene are an early event in colorectal tumorigenesis andstable expression in colorectal tumor at various stages of development.（3） The digital proteintruncation test labeled with fluorescent Lys-t-RNA is rapide, sensitive, high-throughput,Non-radioactive and direct screening procedure of gene mutations.