Little is known about the role of molecules involved in cell-cell interacti
ons during the progression of renal cell carcinoma (RCC). We investigated t
he expression of plakoglobin (a component of the cadherin-catenin adhesion
system) in 94 samples of normal kidney tissue from patients with RCC, in 10
9 primary renal cell carcinomas and in 16 metastases by immunohistochemistr
y. Expression of plakoglobin was significantly diminished in tumor tissue,
particularly in metastatic lesions, as compared to normal kidney tissue (p<
0.001). Follow-up data were available from 87 patients. Patients with a dif
fuse plakoglobin expression (91-100% positive cells) in primary tumor tissu
e had a significant better survival rate than patients with a disturbed pla
koglobin expression (p<0.05) as determined by the log rank test. These resu
lts indicate that loss of plakoglobin may play an important role in maligna
nt transformation of renal cells. Plakoglobin expression status could give
additional information about the individual prognosis.