VGLL4 and esophageal squamous cell carcinoma: Decreased expression level of VGLL4 has been observed in multiple types of tumors including gastric cancer (Jiao et al., 2014), lung cancer (Zhang et al., 2014), breast cancer (Zhang et al., 2017), colorectal cancer (Jiao et al., 2017), and esophageal squamous cell carcinoma (ESCC) (Jiang et al., 2015).