Immunohistochemical analysis of nm23 protein in transitional cell carcinoma of the bladder

To elucidate the clinical significance of the nm23 gene product in transitional cell carcinoma (TCC) of the bladder.

The immunoreactivity of nm23 protein and proliferating cell nuclear antigen (PCNA) were evaluated in paraffin-embedded tumour samples obtained from 74 patients with TCC of the bladder who underwent total cystectomy between 1981 and 1993 and compared with the histological findings and clinical outcome.

The immunoreactivity of nm23 protein was positive near basement membrane in normal transitional epithelium and superficial TCCs; it could also be positive at the invasive front of TCCs. The immunoreactivity of nm23 protein in TCCs was significantly higher than that in normal transitional epithelium and correlated significantly with the expression of PCNA and with histological grade. Similarly, immunoreactivity was significantly higher in invasive TCCs than in superficial TCCs; however, there was no significant difference between superficial TCCs and normal transitional epithelium. Immunoreactivity of nm23 protein was not associated with the early development of metastasis after radical surgery or with a favorable clinical outcome.

Immunoreactivity of nm23 protein appeared to be associated with the proliferation and progression of TCC of the bladder. The potential role of nm23 as a suppressor of the metastatic activity of tumours was less prominent, partly because of mutations of nm23 in TCCs of the bladder.