MiT family metastatic carcinoma

Two types of tumors are included, each associated with the presence of fusion genes for two transcription factors (TFE3 and TFEB). xp11 translocation causes fusion of the TFE3 gene; t(6;11) causes MALAT1-TFEB fusion. This tumor is more common in childhood and accounts for only 6% to 4% of adult-onset renal cell carcinomas. t(6;11) renal cell carcinomas are less common than Xp11-translocated renal cell carcinomas. It is largely non-characteristic. Microscopically, Xp11-translocated renal cell carcinoma appears as a papilla formed by clear cells with scattered sand-like calcifications, whereas t(6;11) translocated renal cell carcinoma appears as a nest of cells of both sizes with basement membrane-like material deposited within. Immunohistochemistry showed decreased expression of epithelial markers such as CK, EMA, PAX8 and other tubular markers; Xp11 renal cell carcinoma: partial expression of melanin markers and TFE3; t(6;11) renal cell carcinoma showed constant expression of melanin markers such as HMB45, Melan A and Cathepsin K, TFEB. The fusion gene of TFE3 or TFEB was detected by FISH.