Divergence of P53, PTEN, PI3K, Akt and mTOR expression in tonsillar cancer.

BACKGROUND

The purpose of this study was to investigate expression differences of p53, PTEN, PI3K, Akt and mTOR according to the human papillomavirus (HPV) infection and to evaluate clinical significance as prognostic markers in patients with locally advanced tonsillar cancer.

METHODS

Sixty-five patients were reviewed. Tissue microarrays were prepared from surgical specimens and stained with antibodies against p53, PTEN, PIK3CA, Akt and mTOR.

RESULTS

Twenty-six patients were HPV-positive. Expression of P53 as well as PIK3CA, Akt and mTOR were not significantly different between the 2 groups. However, total PTEN (nuclear and cytoplasmic PTEN) expression was significantly frequent in HPV-positive group. Both overall survival (OS) and disease-free survival (DFS) were significantly different between the 2 groups. Nuclear PTEN expression in the cancer area and pathological nodal stage were significantly correlated with DFS.

CONCLUSION

Our study suggests that the presence of PTEN expression with predisposition to nucleus more frequently observed in HPV-positive tonsillar cancers are significantly associated with favorable survival outcome, independent of activated PI3K/Akt/mTOR cell survival pathway.