HPV infection has ‘distinct’ etiologic role in oral cancer
MedWire News: Infection with human papillomavirus (HPV) has a unique etiologic role in the development of oral squamous cell carcinoma (OSCC), study findings suggest.
Intriguingly, the study also found evidence that HPV-associated OSCC is a distinct form of oral cancer that carries a better prognosis than other forms of the disease.
The research was undertaken by Yaoh-Shiang Lin (Tri-Service General Hospital, Taipei, Taiwan) and co-workers and was designed to elucidate the role of HPV infection in oral carcinogenesis.
The team obtained tissue specimens from 65 patients with OSCC and analyzed them using molecular techniques including in-situ hybridization and immunohistochemistry.
Results, reported in the Journal of Oral Pathology and Medicine, showed that 24 cases (37%) tested positive for HPV on tissue microarray.
Interestingly, 14 of these cases also tested positive for p16INK4A, a tumor suppressor protein. There was a strong association between positive p16INK4A immunostaining and immunohistochemistry evidence for HPV infection, note the authors.
Additionally, 11 of the HPV-positive cases showed overexpression of p53, another tumor suppressor protein. Just three of the p53-positive cases were also positive for p16INK4A, however, and p53 overexpression was found in the majority of HPV-negative cases.
Lin's team then obtained clinicopathologic data for the 65 patients and looked for correlations with HPV infection.
They found that HPV status was unrelated to gender, age, location, status of lymph node metastasis, and histologic grading.
By contrast, HPV status was significantly correlated with tumor size/extent and with OSCC stage, such that HPV-positive tumors tended to be smaller and at an earlier stage than HPV-negative tumors.
Overall survival at 5 years was 38.5%. However, survival differed by HPV and p16INK4A status, being significantly better in patients with tumors that tested positive for either marker, and by p53 status, being significantly better in those with tumors that tested negative.
Discussing their findings, Lin et al note that oncogenic HPV infection has a well-established association with uterine cervical and anogenital carcinomas, whereas its relationship to OSCC is less clear.
"Based on our data, more than one-third of cases of OSCC showed evidence of HPV via immunohistochemistry," they write.
"Our data provide strong evidence that HPV are etiologically linked to a defined subset of OSCC. HPV-associated tests including in-situ hybridization and immunohistochemistry comprise distinct molecular techniques which may serve as clinically accessible markers."
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By Joanna Lyford