Argani Pedram
Department of Pathology, The Johns Hopkins University School of Medicine, The Johns Hopkins Hospital, 401 North Broadway, Weinberg 2242, Baltimore, Maryland 21231.
Semin Diagn Pathol. 2015 Mar;32(2):103-13. doi: 10.1053/j.semdp.2015.02.003. Epub 2015 Feb 4.
The MiT subfamily of transcription factors includes TFE3, TFEB, TFC, and MiTF. Gene fusions involving two of these transcription factors have been identified in renal cell carcinoma (RCC). The Xp11 translocation RCCs were first officially recognized in the 2004 WHO renal tumor classification, and harbor gene fusions involving TFE3. The t(6;11) RCCs harbor a specific Alpha-TFEB gene fusion and were first officially recognized in the 2013 International Society of Urologic Pathology (ISUP) Vancouver classification of renal neoplasia. These two subtypes of translocation RCC have many similarities. Both were initially described in and disproportionately involve young patients, though adult translocation RCC may overall outnumber pediatric cases. Both often have unusual and distinctive morphologies; the Xp11 translocation RCCs frequently have clear cells with papillary architecture and abundant psammomatous bodies, while the t(6;11) RCCs frequently have a biphasic appearance with both large and small epithelioid cells and nodules of basement membrane material. However, the morphology of these two neoplasms can overlap, with one mimicking the other. Both of these RCCs underexpress epithelial immunohistochemical markers like cytokeratin and epithelial membrane antigen (EMA) relative to most other RCCs. Unlike other RCCs, both frequently express the cysteine protease cathepsin k and often express melanocytic markers like HMB45 and Melan A. Finally, TFE3 and TFEB have overlapping functional activity as these two transcription factors frequently heterodimerize and bind to the same targets. Therefore, on the basis of clinical, morphologic, immunohistochemical, and genetic similarities, the 2013 ISUP Vancouver classification of renal neoplasia grouped these two neoplasms together under the heading of "MiT family translocation RCC." This review summarizes our current knowledge of these recently described RCCs.
转录因子的MiT亚家族包括TFE3、TFEB、TFC和MiTF。在肾细胞癌（RCC）中已鉴定出涉及这些转录因子中的两种的基因融合。Xp11易位性肾细胞癌在2004年世界卫生组织肾肿瘤分类中首次被正式认可，并且含有涉及TFE3的基因融合。t(6;11)肾细胞癌含有特定的α-TFEB基因融合，在2013年国际泌尿病理学会（ISUP）温哥华肾肿瘤分类中首次被正式认可。这两种易位性肾细胞癌亚型有许多相似之处。两者最初都在年轻患者中被描述且在年轻患者中不成比例地多见，尽管成人易位性肾细胞癌总体上可能比儿童病例更多。两者通常都有不寻常且独特的形态；Xp11易位性肾细胞癌经常有具有乳头结构和丰富砂粒体的透明细胞，而t(6;11)肾细胞癌经常有大小上皮样细胞和基底膜物质结节的双相外观。然而，这两种肿瘤的形态可能重叠，一种可模仿另一种。相对于大多数其他肾细胞癌，这两种肾细胞癌均低表达上皮免疫组化标志物，如细胞角蛋白和上皮膜抗原（EMA）。与其他肾细胞癌不同，两者均经常表达半胱氨酸蛋白酶组织蛋白酶k且经常表达黑素细胞标志物，如HMB45和Melan A。最后，TFE3和TFEB具有重叠的功能活性，因为这两种转录因子经常异二聚化并结合相同的靶点。因此，基于临床、形态学、免疫组化和遗传学相似性，2013年ISUP温哥华肾肿瘤分类将这两种肿瘤归为“MiT家族易位性肾细胞癌”类别。本综述总结了我们目前对这些最近描述的肾细胞癌的认识。
