TFE3 and renal cell carcinoma: Xp11.2 renal cell carcinomas are defined by at lest six different translocations involving Xp11.2 chromosome, all of which result in a gene fusion involving the TFE3 (transcription factor E3) gene.7–16 This subtype of renal cell tumour occurs predominantly in the paediatric group where it accounts for 20–40% of paediatric renal cell carcinoma.