The Detection And Analysis Of The Mutations On The D-loop Region Of Mitochondrial DNA In Laryngocarcinoma

Objective:Mitochondria are organelles that do not depend on the nucleargenome replication, transcription and translation.More and more studiesshow that abnormal change of mitochondrial DNA plays an importantrole in tumorigenesis. Because ofthe lack of the protection of the histone,and with a poor restoration system，mitochondrial DNA becomes thetarget of various damage factors, and especially the displacementloop(D-loop)region，which has a high mutation rate.The D-loop region ofmitochondrial DNA regulate transcription and replication ofmitochondrial DNA.Thereby we investigate the mutations on the D-loopregion of mitochondrial DNA in laryngocarcinoma， and study therelationship between laryngocarcinoma and the mutations on the D-loopregion of mitochondrial DNA．Methods:laryngocarcinoma and para-cancerous normal tissues were taken fromthe resected specimens of40patients with laryngocarcinoma whounderwent surgery in the Second Hospital of Jilin University. ThemtDNA displacement loop(D-loop)fragments and partial coding regionswere amplified by PCR．Direct sequencing was followed，the mutations were examined， summarized and analyzed the relations withlaryngocarcinoma.Result:In40samples,102polymorphisms were found,18(45％) tumorspresented somatic mtDNA mutations. Mutations are mainly concentratedin the HVⅠ region, the type of mutation is the substitution and insertionof a single base，20MSI were found,which mainly concentrated in D310.Conclusion:The D-loop region of mitochondrial DNA is a highly polymorphricand mutable region, detection the mutations on the D-loop region ofmitochondrial DNA may be used in the early diagnosis of the tumor.