PTTG1 and esophageal squamous cell carcinoma: One study using RT-PCR of 48 cases of ESCC and its matched samples revealed that PTTG1 expression was upregulated in ESCC, and the average expression level in tumor tissue was 2.19 times than that of normal tissue (0.105 vs. 0.048) (Shibata et al., 2002).