AGK and esophageal squamous cell carcinoma: Importantly, AGK has been identified as a key oncogene that is highly expressed in a range of tumor types, such as prostate cancer (Spiegel and Milstien, 2005; Nouh et al., 2009; Zeng et al., 2009), breast cancer (Wang et al., 2014), cervical squamous cell carcinoma (Sun et al., 2016), and esophageal squamous cell carcinoma (ESCC) (Chen et al., 2013).