MiT Family Translocation Renal Cell Carcinomas

These tumors are caused by two types of translocations involving TFE3 (transcription factor E3) and TFEB genes which are belong to the Microphtalmia-associated transcriptional factor family (MiT family) (2,3). TFE3 is located on Xp11.2, while TFEB is on chromosome 6. Tumors showing Xp11 translocation are much more common than those involving TFEB translocations. The most common subtypes of gene fusions are ASPSCR1-TFE3 and PRCC-TFE3 (1,3). t(6:11) RCC is the rare form of translocation RCCs which harbors gene fusion among TFEB and MALAT-1 (2). These gene rearrangements result in overexpression of several fusion proteins including TFE3 and TFEB which can be demonstrated with a nuclear labeling by immunohistochemistry as a sensitive and specific diagnostic method for each subtype.