Human papillomavirus type 16 infection and local lymph node metastasis in patients with squamous cell carcinoma

Human papillomavirus (HPV) infection is known to be an independent etiologic factor for oral squamous cell carcinoma (OSCC). Especially, HPV-16 is associated with a significant risk of developing OSCC. The most important prognostic factor in OSCC is local lymph node metastasis (LNM); therefore, knowledge of LNM status is crucial for selecting proper treatment plans. However, it is not clarify relationship between HPV-16 infection and LNM in OSCC. The purpose of this study was to determine the role of HPV-16 infection in LNM in OSCC. We analyzed 130 cases of OSCC (100 cases of OSCC without LNM; 30 cases of OSCC with LNM). HPV-16 infection was detected by PCR, immunohistochemical examination and in situ hybridization. HPV-16 positivity rates among primary tumor (PT) specimens without LNM were 43.0 % (43/100), and HPV-16 positivity rates among PT specimens with LNM were 26.7 % (8/30). In addition, HPV-16 positivity rates in both PT and LNM specimens in 30 OSCC patients with LNM were 10 % (3/30). OSCC with HPV-16 DNA detected by PCR showed positive staining on immunohistochemical examination and in situ hybridization. The HPV-16 infection rate in OSCC with LNM was significantly lower than that for OSCC without LNM. In the case of OSCC with LNM, HPV-16 infection rates for both in PT and LNM were low. This suggests that HPV-16 positive cases had a significantly lower risk of LNM when compared with patients having HPV-16 negative OSCC. The results of the present study suggest that HPV status in OSCC is able to act as a marker for risk of LNM.