Pedram Argani
The MiT subfamily of transcription factors includes TFE3, TFEB, TFEC and MITF. Gene fusions involving two of these transcription factors have been well characterized in two subtypes of renal cell carcinoma (RCC): TFE3-rearranged RCC (also known as Xp11 translocation RCC) and TFEB-rearranged RCC (which typically harbour a t(6;11)(p21;q12) translocation). TFE3 and TFEB have overlapping functional activity, which explains why these two subtypes of translocation RCC have many morphologic similarities and express similar downstream targets. Therefore, these two neoplasms are grouped together under the heading of 'MiT family translocation RCC'. TFE3-rearranged PEComas and TFEB-amplified RCC are more recently described related neoplasms harbouring alterations in these same genes. This review summarizes our current knowledge of these molecularly defined neoplasms, and differential diagnostic considerations.