Overexpression of cyclin D1, D3, and p21 in an infantile renal carcinoma with Xp11.2 TFE3-gene fusion.

Renal carcinomas harboring the TFE-3 translocation are rare and occur predominately in children and adolescents. Here, we report a case of infantile renal carcinoma with TFE3 translocation and show that the cell cycle is deregulated in this type of carcinoma. It is characterized by nuclear accumulation of cyclin D1 and D3 in combination with high levels of cyclin-dependent kinase inhibitor p21Cip1/Waf1 but without accumulation of p53, p16INK4a, or mdm2. The combined overexpression of p21, cyclin D1, and cyclin D3 was found exclusively in this type but not in other, more common types of renal carcinoma/oncocytoma (n=27). These results further underscore that renal carcinomas with Xp11. 2 translocations/TFE3-gene fusion represent a special type of renal neoplasm showing deregulation of specific cell cycle components. The analysis of further cases has to prove whether the derangement of the cell cycle is uniform and correlates with the specific type of molecular genetic derangement.