E2F transcription factor 2 variants as predictive biomarkers for recurrence risk in patients with squamous cell carcinoma of the oropharynx

Because E2F transcription factor 2 (E2F2) promoter polymorphisms have been implicated in carcinogenesis and prognosis, we investigated associations between genetic variants in five E2F2 promoter polymorphisms and recurrence risk of squamous cell carcinoma of the oropharynx (SCCOP) in 1 008 patients. A log-rank test and multivariable Cox models were used to assess the associations. Compared with patients with variant genotypes of E2F2-rs2742976 and E2F2-rs3218123, patients with common homozygous genotypes had better disease-free survival (both log-rank, P < 0.001) and lower SCCOP recurrence risk (HR, 0.4, 95% CI, 0.3–0.6 and HR, 0.3, 95% CI, 0.2–0.5, respectively) after multivariable adjustment. Furthermore, among patients with HPV16-positive tumors, those with common homozygous genotypes of E2F2-rs2742976 and E2F2-rs3218123 had better disease-free survival rates (both log-rank, P < 0.001) and lower recurrence risk (HR, 0.1, 95% CI, 0.1–0.4 and HR, 0.1, 95% CI, 0.0–0.2, respectively) than patients with variant genotypes. However, no significant differences were found for the other three polymorphisms. After combining the risk genotypes of the five polymorphisms and using the high-risk group (2–5 risk genotypes) as the reference group, we found that the low-risk groups (0 or 1 risk genotype) had significantly lower recurrence risk among all patients (HR, 0.4, 95% CI, 0.3–0.6) and among HPV16-positive patients (HR, 0.2, 95% CI, 0.1–0.5). Our findings suggest that E2F2 polymorphisms may individually or jointly modify SCCOP recurrence risk, particularly for SCCOP patients with HPV16-positive tumors.