Assessment of p53 and HER-2/neu genes status and protein products in oral squamous cell carcinomas.

Identification of the genes involved in tumor initiation and progression has led to development of new markers and generated targets for new drugs. This study aimed to evaluate p53 and HER-2/neu genes status of and their protein products in oral cancer patients. Tumor specimens from 116 cases diagnosed with oral squamous cell carcinoma were analyzed. P53 and HER-2/neu immunoreactivity were studied. FISH analysis was performed to elucidate p53 and HER-2/neu gene status. Male cases represented 84% of the group. The majority of cases were between 51-60 years and moderately differentiated oral carcinoma had an incidence of 58.6%. Thirty-four cases showed p53 overexpression, negative immunoreaction was observed in 16.37% of cases. 66.38% of cases had p53 deletion, with an increased rate observed in neoplasms of the tongue. Immunohistochemical analysis of HER-2/neu receptor protein revealed that 76.72% were negative, 5.17% had weak immunostaining, 14.65% had +2 score, the others had +3 score. 24.1% of cases were analyzed using FISH technique, of which 25% were without amplification, but with polysomy for chromosome 17. 18.1% of total cases were amplified, with the rate HER-2/neu:CEP17 higher than 2. Of the 77 cases with a single p53 allele, 20 associated HER-2/neu amplification, 31 had positive anti-HER-2/neu immunoreaction, but did not have HER-2/neu:CEP17 rate >2. There was a significant association between HER-2/neu amplification and deletion of a p53 allele. These results could justify more extensive research to assess p53 and HER-2/neu gene status as significant prognostic factors in oral cancers.