OBJECTIVETo investigate the relationship between HPV-DNA status and p16 protein expression in oropharyngeal squamous cell carcinoma (OSCC) and their clinical significance.

METHODSSixty-six patients with oropharyngeal squamous cell carcinomas treated in the Cancer Hospital of Chinese Academy of Medical Sciences from Jan. 1999 to Dec. 2009 were included in this study. Their formalin-fixed and paraffin-embedded tumor tissue blocks met the eligibility criteria and were used in this study. A "sandwich" technique was used to prepare paraffin sections for HPV-DNA analysis. HPV-DNA was detected using the SPF10 LiPA25 version 1 assay. The expression of p16 protein was detected by immunohistochemistry. The survival rates of patients with different HPV-DNA and p16 protein status were analyzed.

RESULTSHPV-DNA was detected in 11 (16.7%) of all specimens. Expression of p16 protein was detected in 9 of the 11 patients with HPV-positive tumors, and in 12 patients of 55 HPV-negative tumors. The expression of p16 protein was highly correlated with the presence of HPV-DNA (P < 0.001). The tumors were classified into three groups based on the p16 protein expression and HPV-DNA status: group A (9 patients): HPV(+) and p16 protein(+); group B (14 patients): HPV-DNA(+)/p16 protein(-) or HPV-DNA(-)/p16 protein(+); and group C (43 patients): HPV-DNA(-)/p16 protein(-). The 3-year OS rates of these 3 groups were 100%, 77.8% and 42.0% (P = 0.001), and their DSS rates were 100%, 77.8% and 46.4%, respectively(P = 0.004).

CONCLUSIONSIn oropharyngeal squamous cell carcinomas, p16 protein expression is highly correlated with the presence of HPV-DNA, and might be a surrogate marker for HPV-positive OSCC. Combination of p16 protein and HPV-DNA status detection may help to more accurately stratify oropharyngeal carcinomas and predict their prognosis.