High levels of RAI3 expression is linked to shortened survival in esophageal cancer patients.

Expression of the retinoic acid-induced protein 3 (RAI3) has been suggested to predict clinical outcome in a variety of malignancies. However, its role in esophageal cancers remains unclear. Immunohistochemical RAI3 staining was analyzed on tissue microarrays containing 359 esophageal adenocarcinomas (EAC) and 254 esophageal squamous cell carcinomas (ESCC). RAI3 immunostaining was typically absent or weakly detectable in the membranes in benign esophageal tissues. RAI3 staining was higher in malignant than in benign esophagus epithelium. High-levels of RAI3 staining were found in 79.2% of interpretable EACs and 55.9% of ESCCs. In EACs, strong RAI3 staining was associated with advanced pathological tumor stage (p < .0001), high UICC stage (p < .0001), high tumor grade (p = .0133), and positive lymph nodal status (p = .0002). Additionally, high RAI3 staining predicted shortened overall survival of EAC and ESCC patients (p = .0298 and p = .0227). RAI3 overexpression is associated with poor prognosis in esophageal cancers. We propose that RAI3 overexpression might play a biologically relevant role of RAI3 in esophageal cancers.