HOPX and esophageal squamous cell carcinoma: Subsequently, HOPX was shown to be downregulated in a wide range of human tumor types, including lung cancer [15], choriocarcinoma [14], head and neck cancers [52,54,63,64,65,66], esophageal squamous cell carcinoma [53], glioblastoma [38], human uterine endometrial cancers (HECs) [59], gastric cancer [55], colorectal cancer [60,61], and pancreatic cancer [62], suggesting a tumor suppressor role for HOPX.