Reduced RBM3 expression is associated with aggressive tumor features in esophageal cancer but not significantly linked to patient outcome

BACKGROUND: RBM3 expression has been suggested as prognostic marker in several cancer types. The purpose of this study was to assess the prevalence and clinical significance of altered RBM3 expression in esophageal cancer. METHODS: RBM3 protein expression was measured by immunohistochemistry using tissue microarrays containing samples from 359 esophageal adenocarcinoma (EAC) and 254 esophageal squamous cell cancer (ESCC) patients with oncological follow-up data. RESULTS: While nuclear RBM3 expression was always high in benign esophageal epithelium, high RBM3 expression was only detectable in 66.4% of interpretable EACs and 59.3% of ESCCs. Decreased RBM3 expression was linked to a subset of EACs with advanced UICC stage and presence of distant metastasis (P = 0.0031 and P = 0.0024). In ESCC, decreased RBM3 expression was associated with advanced UICC stage, high tumor stage, and positive lymph node status (P = 0.0213, P = 0.0061, and P = 0.0192). However, RBM3 expression was largely unrelated to survival of patients with esophageal cancer (EAC: P = 0.212 and ESCC: P = 0.5992). CONCLUSIONS: In summary, the present study shows that decreased RBM3 expression is associated with unfavourable esophageal cancer phenotype, but not significantly linked to patient prognosis.