Loss of cell adhesion is a critical event in the development of tumour invasiveness and metastases. Although loss of cadherin expression has been demonstrated to be associated with increased invasiveness and metastatic potential in some tumours, others, including renal carcinoma, show no such correlation. The aim of this study was to demonstrate that cell adhesion could be lost in phorbol ester-treated renal epithelial cells and renal tumour cells without loss of A-CAM expression. The model used has been shown previously to mimic changes that occur in the progression of renal carcinoma. We found that A-CAM expression persists on the lateral surfaces of phorbol ester-treated cells even though these cells lose cell-cell adhesion. Similar findings were seen in renal carcinoma cells in culture. We conclude that loss of cell adhesion between tumour cells may other either by loss of cadherins or as a result of loss cadherin function occurring as a consequence of cell transformation.