Increasing expression of hypoxia-inducible proteins in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence.

Hypoxia-associated markers are involved in the progression of several malignancies, but are relatively unstudied in Barrett's carcinogenesis. Our aim was to assess the immunohistochemical expression of hypoxia-inducible factor (HIF)-1alpha, HIF-2alpha, erythropoietin (Epo), Epo receptor (Epo-R), Glut-1 and vascular endothelial growth factor (VEGF) along with Ki67/MIB-1 in the Barrett's metaplasia-dysplasia-adenocarcinoma sequence. Endoscopic biopsies of normal squamous epithelium (NSE) (n=20), columnar-lined oesophagus (CLO) (n=15), CLO with intestinal metaplasia (n=20), dysplasia (n=17) and Barrett's type adenocarcinoma (n=20) were obtained. Immunohistochemistry was performed on the paraffin-embedded tissue. A score was calculated for each marker (range 0-300) by multiplying intensity (none 0, weak 1, moderate 2, strong 3) by percentage of expression (range 0-100). Significant increases in the expression of HIF-2alpha (P=0.014), VEGF (P