The TFE3 gene is located on chromosome Xp11.23. The TFE3 break apart FISH probe is designed to label both ends of the TFE3 gene, respectively. A 470 Kb orange probe is designed at the 3′ end of the TFE3 gene, and a 580 Kb green probe is designed at the 5′ end of the TFE3 gene.

Xp11.2 translocation renal cell carcinoma is common in children (approximately one-third of cases) but rare in adults. Most cases are already advanced at diagnosis, with no specific imaging features reported. Xp11.2 translocation RCC differs from other common renal cancers in being insensitive to adjuvant therapies such as immunotherapy, radiotherapy, and chemotherapy, and clinically often presents with perinephric lymph node metastasis. TFE3 protein is highly expressed in this type, but its specificity is only 79%, as high expression also occurs in granular cell tumors, adrenal cortical carcinoma, perivascular epithelioid cell tumors, and high-grade myxofibrosarcoma.