Over the past decade, it has become increasingly clear that a subset of RCC are characterized by a variety of chromosomal translocations involving the TFE3 gene with a breakpoint at Xp11.2, resulting in fusion with one of several translocation partners, such as PRCC-TFE3, ASPL-TFE3, PSF-TFE3, CLTC-TFE3, and NonO-TFE320. The gene discussed is TFE3; the disease is renal cell carcinoma.