Analysis of hMSH2 Mismatch Repair Protein Expression in Dysplasia, Carcinoma In Situ and Invasive Squamous Cell Carcinoma of the Vocal Folds

Abstract

The expression pattern of hMSH2 mismatch repair protein during the progression of benign epithelium to vocal fold invasive squamous cell carcinoma has not been previously described. Nor has the correlation between the hMSH2 protein expression and the clinicopathologic features of the vocal fold dysplasia and carcinoma been examined. Hypothesis: “The progression of benign epithelium to invasive squamous cell carcinoma of the vocal folds is associated with reduction of the hMSH2 mismatch repair protein expression.” Methods: Vocal fold biopsies were obtained from 20 patients with mild and moderate dysplasia: 10 patients with severe dysplasia (squamous cell carcinoma in situ) and 20 patients with invasive squamous cell carcinoma. The expression pattern of hMSH2 protein was examined by using immunoperoxidase-staining methods and mouse monoclonal antibodies. The results were scored as the percentage of hMSH2 positively stained cells. Results: The mean values of hMSH2 positively stained cells decreased gradually with the transitions from normal epithelium to dysplasia and finally to invasive squamous cell carcinoma. There was a negative correlation between the expression of hMSH2 and the degree of dysplasia, that is, as the severity of the dysplasia increases at the microscopic level, there was a decrease in the expression values of the hMSH2 protein. Conclusions: We report, for the first time, that the reduced expression of the hMSH2 mismatch repair protein is related to the progression of the benign epithelium to invasive squamous cell carcinoma of the vocal folds.

Keywords:

• Mismatch repair
• Proteins and vocal folds