Correlation between sigma2 receptor protein expression and histopathologic grade in human bladder cancer

Sigma 2 (σ 2 ) receptor proteins are overexpressed in several tissues and tumour cell lines. Although the biomolecular mechanism of this overexpression must be elucidated, σ 2 receptor was considered a potential biomarker for monitoring solid tumour proliferation. In this study, we verified first σ 2 receptor overexpression by saturation analysis with radioligand in six human bladder cancer specimens, then if a possible correlation could be established between σ 2 overexpression and tumour tissue stage and grade. The results displayed that σ 2 receptor protein was normally expressed in human bladder and overexpressed in the case of high-grade transitional cell carcinomas. Moreover, these receptors were undetected in a low-grade squamous cell carcinoma and in a very rare form of anaplastic, large cells plasmacytoid cancer.