OVEREXPRESSED CYCLIN D1 PROTEIN RELATED TO P53 AND RETINOBLASTOMA PROTEINS IN TRANSITIONAL-CELL CARCINOMA OF THE URINARY-TRACT

We employed immunohistochemical methods to investigate the overexpress ion of cyclin D1 protein as well as p53 protein and retinoblastoma pro tein (pRb) in 57 patients with transitional cell carcinoma (TCC) of th e urinary tract, in order to determine their frequency and significanc e, and also association with the clinicopathological behavior of this tumor. Nuclear immunostaining with cyclin D1 antibody revealed 7 homog eneously stained tumors (12.3%), including 4 heterogeneous pRb express ions, of which only one was also positive for p53. Positive immunostai ning with each antibody to p53 or pRb was obtained in 15 (26.3%) and 4 9 (86%) tumors, respectively. The 49 pRb-positive tumors included 6 ho mogeneous and 43 heterogeneous nuclear immunostaining patterns. The re maining pRb-negative 8 tumors included 5 cyclin D1-negative tumors. Th e prevalence of p53 staining was higher in high-grade (P<0.05) and inv asive types of tumors (P<0.05) than the other types studied. On the ot her hand, no significant relationship was found between cyclin D1- or pRb-immunoreactivity and clinicopathological factors. These findings p rovide evidence for infrequent cyclin D1 protein overexpression in TCC independently associated with p53 protein and/or pRb overexpression.