Objectives: Endothelin-1 (ET-1) and its receptors ET(A)R and ET(B)R, referred to as the Endothelin-axis, play an emerging role in cancer. We examined the ET-axis immunohistochemically in invasive bladder cancer.
Methods: Tumor specimens from 157 patients after cystectomy were stained immunohistochemically for ET-1, ET(A)R and ET(B)R. After semiquantitative analysis the staining results were correlated with clinicopathological parameters and survival rates.
Results: Overexpression of ET-1, ET(A)R and ET(B)R was identified in 26.8%, 58.8% and 76.9% of cases, respectively. No association with TNM staging and histologic grading was found. However, patients with ET(B)R expression tended to have organ-confined tumors (p=0.16) and no vascular invasion (p=0.09), the latter being statistically significant in the subgroup of G3 tumors (p=0.02). ET(B)R overexpression was associated with favorable disease-free survival (p=0.04).
Conclusions: The ET-axis is overexpressed in bladder cancer, ET(B)R predominating in this entity and being associated with a more favorable prognosis. Further studies are warranted to elucidate the role of the ET-axis as a molecular target in bladder cancer.