The loss of retinoblastoma gene in association with c-myc and transforming growth factor-beta 1 gene expression in human bladder cancer

Abstract

Purpose: We investigate the roles and possible interactions of the retinoblastoma, transforming growth factor-beta 1 and c-myc genes in bladder cancer.

Materials and methods: The expression of these 3 genes was examined in 38 biopsy specimens of human bladder cancer by immunohistochemical analysis or Northern blotting.

Results: Loss of the retinoblastoma protein expression was most significantly correlated with high grade cancer. Over expression of c-myc or expression of transforming growth factor-beta 1 was less associated with tumor grade or stage, although c-myc over expression defined stage Ta against other stage tumors, since no stage Ta lesions had increased c-myc expression. Finally, loss of retinoblastoma gene function did not correlate with either c-myc or transforming growth factor-beta 1 expression.

Conclusions: These results further support that retinoblastoma gene inactivation is an important factor in the progression of bladder cancer, and suggest that transforming growth factor-beta 1 and c-myc are not regulators or are not regulated by retinoblastoma gene expression.