Differing expression of bax and bcl-3 may influence the different cure rates in mouth and orophayrngeal cancer
AIM: To determine the reason for the differing cure rates of cancers between the mouth and oropharynx. MATERIALS AND METHODS: To achieve our aim we carried out immunohistochemistry on paraffin-embedded tissue from 31 oral and 38 oropharyngeal squamous carcinomas using the streptavidin-biotin/HRP method. RESULTS: The results from this study revealed the mean percentage of bax and bcl-2 expression was higher in the oropharyngeal samples (56.34% and 97.36%, respectively) than in the oral samples (6.6% and 82.38%, respectively). In the oral carcinomas bcl-2 was expressed in a higher percentage of cells than bax, and a high proportion of cases were bcl-2 positive in the absence of significant bax expression. In contrast the oropharyngeal cases showed a high percentage of cells expresssing both bcl-2 and bax. CONCLUSION: The predominance of anti-apoptotic bcl-2 over the pro-apoptotic bax may result in a survival advantage of the cells of oral carcinomas over the cells of the oropharynx. Tumours of the oral cavity have been found to be clinically more radioresistant than those of the oropharynx. These findings may have implications for radiotherapy treatment since the cells of oral carcinomas may already have a survival advantage and the carcinomas may be less likely to respond to treatment.
Andrews
N
(Departments of Otolaryngology and Pathology, Royal Liverpool University Hospital, Liverpool and J.K. Douglas Laboratory, Clatterbridge Centre for Oncology, Clatterbridge, UK).
Helliwell
T
Walker
C
Jones
AS