Pathology Center, Seegene Medical Foundation, Seoul, Republic of Korea.
Department of Pathology and Translational Genomics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
Anticancer Res. 2023 Apr;43(4):1785-1795. doi: 10.21873/anticanres.16332.
BACKGROUND/AIM: The utility of mismatch repair (MMR) immunohistochemistry (IHC) and microsatellite instability (MSI) testing in uterine mesonephric-like adenocarcinoma (MLA) has seldom been reported. This study aimed to compare MMR IHC and MSI testing in uterine MLA.
We analyzed the MMR protein expression of 25 patients with MLA and compared the results with the MSI status.
Of the cases, one (4.0%) was initially interpreted to have a loss of mutS homolog 2 (MSH2) and mutS homolog 6 (MSH6) expression, and eight (32.0%) to have a loss of MSH6 immunoreactivity. Upon re-evaluation of the slides and repeat IHC, all cases were revealed to demonstrate at least focal (5-20%) immunoreactivity for MSH2 or MSH6. MSI testing revealed all cases to be microsatellite stable (MSS).
Uterine MLA is an MSS/MMR-proficient tumor. We observed complete concordance between MMR IHC and MSI testing. MMR IHC should be carefully interpreted, and discordant cases must be thoroughly reviewed. Repeat IHC and confirmatory MSI testing may be beneficial in resolving uncertain cases.
背景/目的：错配修复（MMR）免疫组化（IHC）和微卫星不稳定性（MSI）检测在子宫中肾样腺癌（MLA）中的应用很少有报道。本研究旨在比较子宫 MLA 中 MMR IHC 和 MSI 检测的应用。
我们分析了 25 例 MLA 患者的 MMR 蛋白表达情况，并将结果与 MSI 状态进行了比较。
其中 1 例（4.0%）最初被解释为缺失 mutS 同源物 2（MSH2）和 mutS 同源物 6（MSH6）表达，8 例（32.0%）被解释为缺失 MSH6 免疫反应性。重新评估切片并重复 IHC 后，所有病例均显示至少有 5-20%的 MSH2 或 MSH6 局灶性（focal）免疫反应性。MSI 检测显示所有病例均为微卫星稳定（MSS）。
子宫 MLA 是一种 MSS/MMR 功能正常的肿瘤。我们观察到 MMR IHC 和 MSI 检测之间完全一致。MMR IHC 应仔细解释，必须彻底审查不一致的病例。重复 IHC 和确认性 MSI 检测可能有助于解决不确定的病例。
