It can be difficult to differentiate diffuse malignant peritoneal mesothelioma (DMPM) from reactive mesothelial hyperplasia (RMH) or peritoneal dissemination of gynecologic malignancies, such as epithelial ovarian cancer (EOC), which cause a large amount of ascites. Detection of the homozygous deletion of p16/CDKN2A (p16) by fluorescence in situ hybridization (FISH) is an effective adjunct in the diagnosis of malignant pleural mesothelioma. The aim of this study was to investigate the ability of the p16 FISH assay to differentiate DMPM from RMH and EOC.
p16 FISH was performed in 28 DMPMs (successful in 19), 30 RMHs, and 40 EOC cases. The cutoff values of p16 FISH were more than 10% for homozygous deletion and more than 40% for heterozygous deletion.
According to the above criteria, nine (47.4%) of 19 successful DMPM cases were homozygous deletion positive, and three (15.8%) of 19 were heterozygous deletion positive, whereas all RMH cases were negative for the p16 deletion. In all four major histologic subtypes of EOC, neither p16 homozygous nor heterozygous deletions were detected. To differentiate DMPM from RMH or EOC, the sensitivity of the p16 homozygous deletion was 32% (9/28), and the specificity was 100%.
Our study suggests that p16 FISH analysis is useful in differentiating DMPM from RMH and EOC when homozygous deletion is detected.
本研究旨在研究p16 FISH在RMH 和EOC中区分DMPM的效能。应用p16 FISH检测了28例DMPMs（成功检测19例）、30例 RMHs和40 例EOC。
P16 FISH检测的阈值是超过10%的纯合性缺失和超过40%的杂合性缺失。依据上述标准，成功的19例DMPM中9例（47.4%）是纯合性缺失阳性，19例中3例(15.8%) 是杂合性缺失阳性，然而所有的RMH 病例 p16 缺失为阴性。在EOC 4种主要的组织类型中均未检测到p16 纯合或杂合性缺失。从RMH 或EOC中区分DMPM，p16 纯合缺失检测的敏感性是32%(9/28)，特异性是100%。
我们的研究显示当检测到同源性缺失时，p16 FISH 对从RMH和EOC 中区分DMPM十分有用。