The Clinical Significance and Relationship of p53 and p21 (p21) in Bladder Cancer

Jeong, Young Beom; Kim, Hyung Jin; Lee, Dong Geun

Abstract

PURPOSE: p53 and p21 act as a cell cycle regulator. p21 has been thought to be an important mediator of p53-induced cell cycle arrest. p53 alterations can induce the uncontrolled growth of tumor cells by loss of p21 expression in cancer patients. The objective of this study was to characterize the alterations of p53 and p21 expression and to assess the relationship between p53 and p21 in bladder cancer patients.
MATERIALS AND METHODS
p53 and p21 expressions were evaluated immunohistochemically in 97 patients of bladder cancer according to grade, stage and recurrence. We compared p53 expression with p21. Nuclear expression was scored as negative, patchy(<20%), heterogeneous(20-75%) or homogeneous(>75%).
RESULTS
p53 was expressed in 34(35.1%) of 97 patients and p21 in 23 patients(23.7%). p53 expression was significantly related with grade(18.2% in lower grade vs. 71% in higher) and stage(18.2% in superficial vs. 57.1% in invasive). p21 was not expressed in 74(76.3%) of 97 patients and not correlated with grade and stage. Recurrence in superficial bladder cancer was lower for patients with p53-negative(27%) than patients with p53-positive(64.3%). There was no correlation between loss of p21 expression and recurrence. Inverse expression of these two proteins was seen in 39 patients(40.2%).
CONCLUSIONS
These results suggest that p21 is induced by p53-dependent pathway, but that there may also indicate p53-independent pathways of induction. p53 could be a reliable indicator of recurrence in superficial bladder cancer.