Altered Retinoblastoma (RB) Protein Expression in Human Malignancies

Abstract

Abstract

Dysfunction of the retinoblastoma (RB) gene has implicated not only in the development of retinoblastoma but also in the initiation and/or progression of some of the most common human malignancies. The RB gene encodes a nuclear phosphoprotein of ∼110 kDa. With a modified antigen-retrieval method, several polyclonal and monoclonal anti-RB antibodies are now available for demonstration of RB protein in formalin-fixed, routinely processed pathological specimens. Differing from the uncertainty about p53 immunoreactivity, the immunohistochemical assay for RB protein has proved to be a sensitive and reliable method for detecting RB gene inactivation. Furthermore, although the literature remains controversial, there is growing evidence suggesting that RB protein status is potentially a prognostic marker in urothelial carcinoma and perhaps also in some other types of human neoplasms. More definitive studies, however, must be conducted before the RB gene can be considered a prognostic factor in clinical practice.