ABSTRACT
<p><b>OBJECTIVE</b>To investigate the association of mutations and expression of MUS81 gene with the tumorigenesis and progression of laryngeal squamous cell carcinoma (LSCC).</p><p><b>METHODS</b>PCR-SSCP and DNA sequencing were carried out to examine mutations at exons 9 and 10 of MUS81 gene in 42 LSCC samples, with paired adjacent normal laryngeal tissues (PANLs) as control. Semi-quantitative RT-PCR and Western blot were used to detect the expression of MUS81 gene in the specimens.</p><p><b>RESULTS</b>No mutation was detected in the control group. Among the 42 LSCC specimens, nineteen (45.2%) were found to harbor mutations, including 11(26.2%) occurring within exon 9, and 8 (19%) within exon 10. Seventeen (40.48%) samples showed lower mRNA level of the MUS81 gene (P<0.01), and same proportion of samples had lower protein level (P<0.01), suggesting that MUS81 gene was similarly down-regulated at both mRNA and protein levels in the LSCC samples. Furthermore, mutations of MUS81 gene did not significantly correlate with TNM stages, age and lymphoid node metastasis (P>0.05). Nor did the expression of MUS81 gene with the TNM stages, age and lymphoid node metastasis in LSCC (P>0.05).</p><p><b>CONCLUSION</b>Mutations and abnormal expression of MUS81 gene in the LSCC tissues were observed, which suggested that abnormalities of MUS81 gene may play an important role in the tumorigenesis of LSCC.</p>