['To evaluate the prognostic impact of p16 immunoreactivity in minimally invasive transitional cell bladder carcinomas (stage T1).', 'Multi-tissue-arrays containing 73 samples of T1 bladder carcinomas were stained immunohistochemically for p16. Additionally, p53 and Ki-67 antigen expression were examined. A multivariate analysis including other prognostically relevant factors like tumor grade and sub-stage was performed.', 'Loss of p16 expression occurred in 54% of cases and was significantly associated with reduced progression-free (p=0.018 by univariate analysis), but not with recurrence-free survival (p=0.341). Median Ki-67 antigen and p53 index were 51% (range, 1-93%) and 10% (range, 0-100%), respectively. Both indices correlated significantly (p=0.041 and p=0.024, respectively) with recurrence-free, but not with progression-free survival. Also tumor grade was significantly associated with tumor recurrence (p=0.006). By multivariate analysis, tumor grade (p=0.008) was identified as an independent predictor of tumor recurrence, whereas p16 expression (p=0.009) was identified as an independent predictor of tumor progression.'] Is p16 immunoreactivity an independent predictor of tumor progression in minimally invasive urothelial bladder carcinoma?