Since little is known about the abundance of RARs and RXRs protein in esophageal SCC in humans, the major focus of the present study was to determine protein levels of RARα, β, γ, and RXRβ in normal, macroscopically unaffected esophageal tissue and SCC of patients with untreated SCC and controls. This evidence concerns the gene RARA and esophageal squamous cell carcinoma.