Receptor activator of nuclear factor kappaB (RANK) is expressed as a late event during malignant progression in Barrett's metaplasia

Receptor activator of NF-kappaB (RANK) activation induces several survival signals including nuclear factor kappaB (NF-kappaB) and activation and upregulation of Bcl-xL. The aim of this work was to determine whether RANK is expressed in oesophageal adenocarcinoma (EA) and its precursor, Barrett's metaplasia (BM). Sections of formalin-fixed and paraffin-embedded tissue from 23 oesophagectomy specimens showing EA and variable degrees of dysplasia in BM were immunohistochemically stained for RANK. All 23 carcinomas (100%) showed strong RANK immunoreactivity in most cancer cells. In 8 cases with high-grade dysplasia (HGD), RANK immunoreactivity was weaker and detected in a smaller percentage of cells. RANK was not detected in any area of BM that was negative for dysplasia (ND) (17 cases), or showed low-grade dysplasia (LGD) (9 cases). These results indicate that RANK is expressed as a late event during malignant progression in BM. Studies are needed to determine whether interfering with RANK signalling affects the survival of EA cells.