Oral cancer: the importance of the evaluation of p53 as a prognostic factor in the surgical and multidisciplinary treatment .

Objective - We have analysed concentrations of the p53 protein in advanced oral carcinomas immunohistochemically and genetically to detect the percentage of overexpression of this antioncogene that indicates a high probability of mutation. This would point to it being a useful prognostic factor, if we consider the importance of the relation between genetic alterations of p53 and poor overall survival. Methods - Seventy-five non-consecutive patients with oral squamous cell carcinoma and metastatic nodes were enrolled if there was homogeneity in histopathological grading (G2) of their tumours, and they were treated according to a multidisciplinary treatment plan (neoadjuvant chemotherapy, surgery, and postoperative radiotherapy). They were 57 men and 18 women (mean age 67, range 57-72 years) who were selected from a total of 420 patients with oral cancer who were under observation from January 1992 to January 2012. Monoclonal antibodies, extraction of DNA, and amplification of the polymerase chain reaction (PCR) were used for the immunohistochemical and genetic analyses. Results - There was a significant inverse correlation between p53 overexpression and response to chemotherapy and a stronger association between high P53 overexpression (%) and a genetic mutation of p53 (p = 0.0001). More than 50% overexpression indicated a strong probability of genetic mutation. There was a significant correlation between sex and site of tumour (p < 0.001). Three prognostic factors were significantly related to prognosis: site of tumour (p = 0.01), response to chemotherapy (p = 0.002), and immuno p53 (p = 0.0001). Conclusions - Our research addresses the need for improved understanding of the prognostic value of p53 in oral SCC.We can verify that in our group 50% of linked p53-antibodies in histopathological specimens seem to indicate a cut-off point. A tumour that is characterised by p53 overexpression of more than 50% indicates a poor prognosis. The oncogenic pattern supplies important elements for diagnostic and prognostic evaluation, in addition to classic screening. These elements are important considering that oral SCC are often at an advanced stage when they are diagnosed and require a multidisciplinary approach to treatment.