Chen C, He X, Jing W Y, Qiu Y, Chen M, Luo T Y, Liu X Y, Chen H J, Zhang H Y, Bu H
Department of Pathology, West China Hospital, Sichuan University, Chengdu 610041, China.
Zhonghua Bing Li Xue Za Zhi. 2022 Mar 8;51(3):190-195. doi: 10.3760/cma.j.cn112151-20211029-00785.
To investigate the value of MDM2 RNA in situ hybridization (RNA-ISH) in diagnosing atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) and dedifferentiated liposarcoma (DDL). A total of 26 ALT/WDL/DDLs diagnosed from March 2017 to May 2019 in West China Hospital, Sichuan University, Chengdu, China and 18 control cases were included. MDM2 RNA-ISH was performed on all samples and compared with the fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) regarding their performance in detecting MDM2. All samples were detected successfully using the three methods. Among 26 ALT/WDL/DDLs, all cases showed MDM2 amplification and positivity for MDM2 RNA-ISH (26/26, 100%). Twenty-four (24/26, 92.3%) of the 26 tested cases were positive for MDM2 IHC while two of them were negative. Eighteen control cases were all negative for MDM2 FISH and RNA-ISH, and 15 (15/18) cases were negative for MDM2 IHC. The sensitivity and specificity of RNA-ISH were both 100%, and those of MDM2 IHC were 92.3% and 83.3%, respectively. Diffuse staining was identified in all MDM2 RNA-ISH positive ALT/WDL/DDLs, but identified in only 8/24 (33.3%) of the MDM2 IHC positive cases. Among the 11 ALT/WDL/DDL samples evaluated on tissue microarray, the positive rate of MDM2 RNA-ISH was 100% with diffuse staining in all cases. The positive rate of MDM2 IHC was 9/11 while only 1 of the 9 cases showed diffuse staining. The result of MDM2 RNA-ISH was identical to that of MDM2 FISH and was overall consistent with that of MDM2 IHC (Kappa=0.763, <0.001). In ALT/WDL/DDLs, results of MDM2 RNA-ISH are highly consistent with those of FISH. MDM2 RNA-ISH is more sensitive and more specific and has more diffuse positive signals than the IHC. The findings indicate that MDM2 RNA-ISH is highly valuable for the diagnosis and differential diagnosis of ALT/WDL/DDLs.
探讨MDM2 RNA原位杂交（RNA-ISH）在诊断非典型脂肪瘤性肿瘤/高分化脂肪肉瘤（ALT/WDL）和去分化脂肪肉瘤（DDL）中的价值。纳入2017年3月至2019年5月在四川大学华西医院诊断的26例ALT/WDL/DDL患者及18例对照病例。对所有样本进行MDM2 RNA-ISH检测，并与荧光原位杂交（FISH）和免疫组织化学（IHC）检测MDM2的性能进行比较。三种方法均成功检测所有样本。26例ALT/WDL/DDL中，所有病例MDM2 RNA-ISH均显示MDM2扩增且阳性（26/26，100%）。26例检测病例中24例（24/26，92.3%）MDM2 IHC阳性，2例阴性。18例对照病例MDM2 FISH和RNA-ISH均为阴性，15例（15/18）MDM2 IHC阴性。RNA-ISH的敏感性和特异性均为100%，MDM2 IHC的敏感性和特异性分别为92.3%和83.3%。所有MDM2 RNA-ISH阳性的ALT/WDL/DDL均见弥漫性染色，但MDM2 IHC阳性病例中仅8/24（33.3%）见弥漫性染色。在组织芯片评估的11例ALT/WDL/DDL样本中，MDM2 RNA-ISH阳性率为100%，所有病例均见弥漫性染色。MDM2 IHC阳性率为9/11，9例中仅1例见弥漫性染色。MDM2 RNA-ISH结果与MDM2 FISH结果一致，与MDM2 IHC结果总体相符（Kappa=0.763，<0.001）。在ALT/WDL/DDL中，MDM2 RNA-ISH结果与FISH结果高度一致。MDM2 RNA-ISH比IHC更敏感、更特异，且弥漫性阳性信号更多。研究结果表明，MDM2 RNA-ISH对ALT/WDL/DDL的诊断及鉴别诊断具有很高的价值。
