Preclinical data have shown that estrogen and selective estrogen receptor modulator treatment decreases tumor growth, proliferation and increase apoptosis in EAC and Barrett's esophagus cell lines [13, 14] and similar effects have been reported in vitro and in vivo for gastric [31, 32] and colorectal cancer [33] and esophageal squamous cell carcinoma (OSSC) [20, 34]. The gene discussed is ESR1; the disease is esophageal squamous cell carcinoma.