Mutation And Expression Of MUS81 In Laryngeal Squamous Cell Carcinoma

IntroductionLaryngeal squamous cell carcinoma ( LSCC) is one of the prevalent tumor of head and neck. Clinical data showed that a tendency of increasing incidence in Northeast China recent years. Like other tumor, tumorigenesis of LSCC is a multiple gene participating in and complicated process of multistep. Tumor progress is strongly associated with abnormality of oncogenes , tumor suppressor genes, cell cycle regulator genes and DNA repair genes. It is very important for MUS81 to stabilize genome. Genetic studies indicate that MUS81 plays a role in recombinant intermediates which is produced during the repairing of DNA damage. It is yet unknown whether MUS81 is related with LSCC or not. Our study indicated that the mutation and expression of MUS81 was related to the tumorigenesis and progression of laryngeal squamous cell carcinoma.Materials and methods1. MaterialsLaryngeal squamous carcinomas ( LSCC) , benign lesion tissues and their paired adjacent normal laryngeal tissues (PANLs) were from the patients admitted to the First Affiliated Hospital of China Medical University. All human tissues were collected following signed patient consent. TRIZOL reagent and Taq DNA polymerase, Reverse - transcription kit and DNA purifaction kit were purchased from Promega company. Reagents for PCR - SSCP were purchased from MERCK and other reagens from Sigma company.2. Methods2. 1 Mutations of MUS81 exons 9 and 10 were detected by PCR - SSCP ( domain of MUS81 spanning exon9 to exon10) and DNA sequencing in 30 cases of LSCC , paired normal tissue as control.2. 2 The expression level of MUS81 mRNA was tested by RT - PCR in the same tissues .Results1. PCR - SSCP analyses of MUS81 in LSCC. There was the MUS81 E9 mutation in patients with tumor (26.67% , 8/30) and the MUS81 E10 mutation in patients with tumor (20% , 6/30) , and there was MUS81 E9 and MUS81 E10 in one patient with tumor(3.33% ,1/30). The resulting mutation indicated that three of all mutation was heterozygosity mutation which happened in MUS81 E9 and others was homozygosity mutation.2. Expression of MUS81 mRNA in LSCC. Semi - quantitative RT - PCR a-nalysis of MUS81 mRNA showed that 40% ( 12/30) of LSCC was down - regulated, compared with PANLs. Statistics analysis of MUS81 mRNA showed significant difference between tumor groups and PANLs groups (t = 2. 208, P <0. 05).3. x~2 test of MUS81 E9, MUS81 E10 mutation and expression have significant correlation. Statistics results indicated that the mutation of MUS81 is related to TMN(P <0.05) , but not to age and lymphoid node diversion. However, the expression of MUS81 is not related to TMN, age and lymphoid node diversion.Conclusion1. The mutation of MUS81 E9 and MUS81 E10 was first found in LSCC.2. The expression of MUS81 was first detected down -regulation in LSCC.3. x~2 test of MUS81 E9, MUS81 E10 mutation and expression have significant correlation. Statistics results indicated that the mutation of MUS81 is related to TMN(P <0.05) , but not to age and lymphoid node diversion. However, the expression of MUS81 is not related to TMN, age and lymphoid node diversion.