PTTG2 and head and neck squamous cell carcinoma: PTTG3P expression was significantly correlated with PTTG1 as well as PTTG2, as was PTTG1 expression with PTTG2. Significant differences between expression levels of PTTG3P, PTTG1 and PTTG2 in head and neck squamous cell carcinomas patients were also observed in clinicopathological contexts.