Transcription factor E3 (TFE3) is a protein expressed in many cell types that are encoded by the TFE3 gene. This gene may be involved in chromosomal translocations that occur in some cancers.Xp11 translocation renal cell carcinomas (RCC) are a recently recognized subset of RCC, characterized by chromosome translocations involving the Xp11.2 break point and resulting in gene fusions involving the TFE3 transcription factor gene that maps to this locus.¹ Alveolar soft part sarcoma (ASPS) is an uncommon soft tissue sarcoma of uncertain differentiation. The hallmark of ASPS is a chromosomal rearrangement at 17q25 and Xp11.² engendering an ASPSCR1-TFE3 fusion gene responsible for an aberrant transcription factor presumably enabling pathogenesis.^1-5