PRB1 and urinary bladder cancer: To examine the effect of MYC on pRB1 protein levels in patient specimens, we analyzed MYC and pRB1 protein levels in a tissue microarray (TMA) containing a cohort of bladder cancer samples (n = 40) using immunohistochemistry (IHC) and found that pRB1 expression was negatively correlated with MYC expression (Fig. 2j, k).