HPV infection in Brazilian oral squamous cell carcinomapatients and its correlation with clinicopathological outcomes

This study aims to investigate human papilloma virus (HPV) frequency in Brazilian patients with oral squamous cell carcinoma (OSCC) in order to establish a clinicopathological profile. It will also examine the correlation between patient survival and HPV expression in primary tumors (PTs), and their matched samples (MSs) of recidives, lymph nodal metastasis (LNM) or necropsies. Eighty-seven PTs and their corresponding 87 MSs were tested for HPV infection by polymerase chain reaction (PCR) using general and type-specific HPV primers. The following data were obtained from patient medical files: primary site, age, gender, tobacco consumption, histological differentiation, recurrences, metastasis, disease-free survival (DFS) and overall survival (OS). Of the 87 patients investigated, 17 (19.5%) were found to have HPV DNA in their tumors. An investigation of all the paraffin-embedded specimens revealed the presence of HPV DNA in 18 of the 174 samples (10.4%), 10 (11.5%) from PTs and 8 (9.2%) from MSs. No virus was detected in the corresponding PT of 7 (8.1%) MSs, and only one patient demonstrated HPV DNA positivity in both samples. The HPV genotypes 16 and 18 were detected in 4 (22.2%) and 3 (16.7%) of the positive samples, respectively. Infection with both genotypes was found in 6 (33.3%) investigated samples, and the HPV genotype was unidentified in 5 (27.8%) samples. The tongue was the most prevalent infected anatomical site. We did not find any significant association between HPV infection and gender, age, histological differentiation, DFS or OS. A significant number of HPV samples were positive among non-smoking patients. Although a possible influence of the virus on tumoral induction cannot be ruled out, the low frequency of OSCC cases that contain HPV does not suggest that this virus has the same etiological influence on patients as tobacco consumption does.