Introduction: In most cases the diagnostic workup of pleural mesotheliomas (MPM) starts with cytological examination of pleural effusion, but histology is needed to confirm the diagnosis. The introduction of BAP1 and MTAP immunohistochemistry have become a powerful tool to confirm the malignant nature of mesothelial proliferations also in cytological specimens. The objective of this study is to determine the concordance of BAP1, MTAP and p16 expression between cytological and histological samples of patients with MPM. Methods: Immunohistochemistry of BAP1, MTAP and p16 was performed on cytological samples and compared with the corresponding histological specimen of 25 patients with MPM. Inflammatory and stromal cells served as positive internal control for all three markers. In addition, samples of 11 patients with reactive mesothelial proliferations served as an external control group. Results: Loss of BAP1, MTAP and p16 expression was found in 68%, 72% and 92% of MPM, respectively. Loss of MTAP was associated with loss of p16 expression in all cases. Concordance of BAP1 between cytological and corresponding histological samples was 100% (kappa coefficient 1; p = 0.008). For MTAP and p16 kappa coefficient was 0.9 (p = 0.01) and 0.8 (p = 0.7788), respectively. Conclusions: Concordant BAP1, MTAP and p16 expression is found between cytological and corresponding histological samples, indicating that a reliable diagnosis of MPM can be made on cytology only. Of the three markers BAP1 and MTAP are most reliable in distinguishing malignant from reactive mesothelial proliferations


中文翻译：

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BAP1、p16 和 MTAP 免疫组织化学在胸膜间皮瘤细胞学和组织学样本中的应用

简介：在大多数情况下，胸膜间皮瘤 (MPM) 的诊断检查从胸腔积液的细胞学检查开始，但需要组织学检查来确认诊断。BAP1 和 MTAP 免疫组织化学的引入已成为确认细胞学标本中间皮增殖恶性性质的有力工具。本研究的目的是确定 MPM 患者细胞学和组织学样本中 BAP1、MTAP 和 p16 表达的一致性。方法：对25例MPM患者的细胞学样本进行BAP1、MTAP和p16的免疫组织化学检测，并与相应的组织学标本进行比较。炎症细胞和基质细胞作为所有三种标记物的阳性内部对照。此外，11 名具有反应性间皮增殖的患者样本作为外部对照组。结果：68%、72% 和 92% 的 MPM 中分别发现 BAP1、MTAP 和 p16 表达缺失。在所有情况下，MTAP 的缺失均与 p16 表达的缺失相关。细胞学样本和相应组织学样本之间的 BAP1 一致性为 100%（kappa 系数 1；p = 0.008）。MTAP 和 p16 kappa 系数分别为 0.9 (p = 0.01) 和 0.8 (p = 0.7788)。结论：在细胞学和相应的组织学样本之间发现一致的 BAP1、MTAP 和 p16 表达，表明仅通过细胞学即可对 MPM 做出可靠的诊断。三种标记物中，BAP1 和 MTAP 在区分恶性间皮增殖和反应性间皮增殖方面最可靠