Immunohistochemical demonstration of cyclin D1 in bladder cancers as an inverse indicator of invasiveness but not an independent prognostic factor

Background: Cyclin D1 is essential for G1 progression through the cell cycle phase. It is a possible proto-oncogene whose aberrant expression may be responsible for the occurrence of some types of human neoplasms. The objective of the present study was to demonstrate immunohistochemically cyclin D1 expression in bladder cancer tissues and establish any relationship with the histologic findings and the clinical course. Methods: Tissue from 102 patients with bladder cancers and bladder tissue from five normal subjects were used for an immunohistochemical study of cyclin D1 using the avidin–biotin complex method. Results: Nuclear staining of cyclin D1 was found in 79 (77%) out of the 102 cases of bladder cancer. The five cases of normal epithelium had no immunostaining for cyclin D1. All grade 1 tumors were positive for cyclin D1. With the advance of tumor grade the incidence of cyclin D1 decreased. All pTa tumors stained positively for cyclin D1, whereas the positive staining rates of invasive tumors were 47% in pT1, 73% in pT2, 31% in pT3 and 0% in pT4 tumors. Although a univariate analysis revealed patients with lesions positive to cyclin D1 had more favorable survival rates than those with negative findings, a multivariate analysis showed that positivity for cyclin D1 is not an independent prognostic factor. No relationship was discovered between positivity for cyclin D1 and tumor recurrence in patients with superficial bladder cancers. Conclusions: These findings suggest that cyclin D1 demonstrated immunohistochemically could be used as an inverse indicator for the level of invasiveness of bladder cancer, but not as an independent prognostic factor.