Transforming Growth Factor-β Binding Receptor Endoglin (CD105) Expression in Esophageal Cancer and in Adjacent Nontumorous Esophagus as Prognostic Predictor of Recurrence

Abstract

We hypothesized that the potent neovascularization marker endoglin (CD105), by differentially highlighting a subset of microvessels (MV) in esophageal cancer (EC), could provide better prognostic/therapeutic information than the panendothelial marker CD34, which also highlights MV. Endoglin messenger ribonucleic acid (mRNA) expression in normal, malignant, and adjacent nontumorous esophagus tissue was quantified by real-time reverse-transcription polymerase chain reaction (RT-PCR). Sections of formalin-fixed, paraffin-embedded tissues were analyzed immunohistochemically for CD105 and CD34. MV density was counted following a standard protocol. Circulating soluble endoglin levels were determined in patient and control sera, and compared with clinical outcome. CD105 mRNA was upregulated by a median factor of 2.89 in ECs versus controls. In 28% of patients, CD105 mRNA was upregulated by a median factor of 2.65 in adjacent non-tumorous versus normal tissue. In tumor tissues, CD105 was stained negatively or positively only in a subset of MV. CD34 always showed positive extensive MV staining. In adjacent nontumorous esophagus, CD105 rarely showed diffuse MV staining, while CD34 stained blood-vessel endothelial cells in all non-neoplastic tissue. CD105 expression was high in residual highly dysplastic Barrett's-type mucosa associated with some adenocarcinomas. No statistically significant difference in endoglin serum levels appeared between patients and normal subjects. Correlation with clinicopathological data showed higher intra-tumor MV-CD105+ scores at more-advanced clinical stages. High-scoring MV-CD105+ patients had significantly shorter disease-free and overall survival; MV-CD34+ density was not survival related. Diffuse CD105 expression in adjacent nontumorous esophagus predicted poorer disease-free and overall survival. Our findings could help identify EC patients who may benefit from targeted anti-angiogenic therapies.