Immunohistochemical Study of p53 and RB Tumor Suppressor Gene Protein in Carcinoma of the Parotid Gland.

The development and progression of cancer are known to be regulated by various oncogenes and tumor suppressor genes. We investigated the expression of p53 and RB proteins in 13 cases of parotid carcinomas, which cases were admitted to the Department of Otorhinolaryngology, Gifu University School of Medicine from January 1989 to September 1998. These cases were investigated by immunohistochemical techniques using p53 and RB monoclonal antibodies. The results were as follows:1) p53 protein nuclear staining was shown in 8 of 13 cases. A significant difference in the expression of p53 proteins was observed between high grade carcinoma groups and low grade carcinoma groups (Fisher's exact test; p=0.03). These results suggest that expression of p53 protein is related to the malignant grade of parotid gland carcinomas.2) RB protein nuclear staining was shown in 7 of 13 cases. A significant difference in the expression of RB protein was not observed between high grade carcinoma groups and low grade carcinoma groups (Fisher's exact test; p=0.27). Expression of RB protein did not appear to be related to malignant grade of parotid gland carcinomas.