PTGIR and oropharynx cancer: Methylation statuses of the PTGIR and TBXA2R promoters were positively correlated with recurrence in patients with oropharyngeal cancer (OR, 2.99; 95% CI 1.13–7.92; P = 0.028 and OR, 5.21; 95% CI 1.63–16.67; P = 0.006, respectively) (Fig. 5).