Abstract
Translocation-associated renal cell carcinoma (t-RCC) is a relatively uncommon subtype of renal cell carcinoma characterized by recurrent gene rearrangements involving the TFE3 or TFEB loci. TFE3 and TFEB are members of the microphthalmia transcription factor (MiT) family, which regulates differentiation in melanocytes and osteoclasts, and MiT family gene fusions activate unique molecular programs that can be detected immunohistochemically. Although the overall clinical behavior of t-RCC is variable, emerging molecular data suggest the possibility of targeted approaches to advanced disease. Thus, distinguishing t-RCC from its morphologic, immunophenotypic, and molecular mimics may have important clinical implications. The differential diagnosis for t-RCC includes a variety of common renal neoplasms, particularly those demonstrating clear cell and papillary features; in addition, because of immunophenotypic overlap and/or shared molecular abnormalities (ie, TFE3 gene rearrangement), a distinctive set of nonepithelial renal tumors may also warrant consideration. Directed ancillary testing is an essential aspect to the workup of t-RCC cases and may include a panel of immunohistochemical stains, such as PAX8, pancytokeratins, epithelial membrane antigen, carbonic anhydrase IX, HMB-45, and Melan-A. Dual-color, break-apart fluorescent in situ hybridization for TFE3 or TFEB gene rearrangement may be helpful in diagnostically challenging cases or when molecular confirmation is needed.
摘要
易位相关的肾细胞癌(t-RCC)是一种较少见的肾细胞癌亚型,其特点是常常有TFE3基因或TFEB位点的基因重排。TFE3和TFEB是小眼转录因子家族成员(MIT),调节黑色素细胞和破骨细胞的分化,MIT家族基因融合激活独特的分子程序,可以采用免疫组化方法检测。虽然t-RCC总体临床行为是不同的,新近分子研究数据提示晚期疾病具有靶向治疗的可能性。因此,从形态学、免疫表型和分子表型相似病变中区分t-RCC可能具有重要的临床意义。对于t-RCC鉴别诊断包括各种常见的肾肿瘤,特别是显示透明细胞和乳头特征的肿瘤;此外,由于免疫表型有重叠和/或共同的分子异常(如:TFE3基因重排),鉴别诊断时也需考虑一些独特的非上皮性肾肿瘤。定向辅助检测是t-RCC病例鉴别诊断的一个必需手段,它可能包括一组免疫组化染色,如PAX8、PCK、EMA、碳酸酐酶IX、HMB-45和Melan-A。TFE3或TFEB基因重排双色荧光断裂位点原位杂交可能有助于挑战性病例的诊断或分子分型确认。
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