Cyclin D1 overexpression is associated with poor prognosis in oropharyngeal cancer

Objectives: To determine the biological characteristics of oropharyngeal squamous cell carcinoma (OpSCC) and related outcome. Design: Retrospective study. Methods: Patients (N=60) with primary OpSCC from 2000 to 2005 were retrospectively identified from Pathology database and the outcome was confirmed through chart review. Among these, 41 biopsy samples with enough tissues were retrieved to construct a tissue microarray for detection of the presence of high-risk human papillomavirus (HPV) using Chromogenic in situ hybridization (CISH) as well as the expression of p16 and cyclin D1 using immunohistochemistry. Main outcome measures: Disease-free survival. Results: Among 60 patients, 39 (65%) patients had no recurrence or died without disease at the last follow-up (disease-free survival or Group 1), and 21 (35%) patients had persistent disease or died of disease (progression-free survival or Group 2). Although follow-up time was twice as long in group 1 (4.7 +/- 2.2 vs. 2.0 +/- 1.6 years; P < 0.0001), there was no difference between the 2 groups in age, gender, smoking/alcohol habits, TNM staging and treatment modalities. Among those 41 cases with available tumour tissues, there was no difference in HPV status and p16 expression between the 2 groups but a significant difference in cyclin D1 expression (P = 0.05). Using Kaplan-Meir survival analysis and log-rank test, cyclin D1 overexpression was highly associated with a poor prognosis when comparing time to outcome (P < 0.0001). Conclusion: Cyclin D1 overexpression is a potential prognostic marker of OpSCC.