E-cadherin expression in renal cell cancer and its significance in metastasis and survival.

Decreased expression of E-cadherin (E-CD), a homotypic intercellular adhesion molecule, is considered to elicit detachment of tumour cells from primary lesions, which is the first stage of metastasis. Since renal cell cancer (RCC) shows a relatively high frequency of metastasis, we focused our interest on E-CD expression in RCC and its clinicopathological implications. We examined E-CD expression in normal kidney and RCC by immunohistochemical staining. In normal kidney, E-CD expression was localised in distal tubules and collecting ducts. In RCC, 20 of 106 primary lesions (18.9%) expressed E-CD, whereas none showed positive staining for eight metastatic lesions. There was a statistically significant correlation between loss of E-CD expression and advanced stages of RCC. Kaplan-Meier analysis showed better prognosis in the group with preserved E-CD expression than without E-CD expression (Cox-Mantel test, P = 0.022, the average follow-up was 32 months or until death). This study suggests that the patients with decreased E-CD expression may be associated with metastasis, resulting in poor prognosis. However, frequency of E-CD expression in RCC is lower than in other cancers, which may be derived from the localised distribution of E-CD expression in normal kidney.