Association between p53 status, human papillomavirus infection, and overall survival in advanced oral cancer after resection and combination systemic treatment

Our previous study on 75 cases of advanced oral squamous cell carcinomas (SCC) treated by neoadjuvant chemotherapy, radical surgery, and radiotherapy showed that overexpression of p53 of more than 50% indicated a strong probability of genetic mutation, and tumours that are characterised by this p53 pattern respond poorly to treatment and have a poor prognosis (p= 0.0001). We have studied the same cohort of patients retrospectively to investigate the incidence of human papillomavirus-16 (HPV16) infection, the relation to the overexpression or mutation of the p53 gene, and the association with overall survival. There were 57 men and 18 women, mean age 67 (range 57-72) years. HPV16 infectivity was found in 66 patients (88%) - 49/57 men (86%) and 17/18 women (94%). There was no significant difference between the sexes (p=0.32). The cumulative survival of the entire group after a follow-up of 38 months was 26% (SE 6.4). The log rank test indicated that the combination of HPV-16 infectivity and p53mutation was significantly related to prognosis (p=0.000). On the other hand HPV16 infectivity alone was not significantly related to prognosis (p=0.78) The incidence of HPV-16 infection decreased with increasing immune p53 expression (p=0.005), whereas that of the HPV16+p53mutation combination increased with increasing immune p53 expression (p=0.000). The results show the importance of the investigation of HPV and p53 expression to define prognosis in oral SCC.