<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">SALLER, JAMES J.</style></author><author><style face="normal" font="default" size="100%">MORA, LINDA B.</style></author><author><style face="normal" font="default" size="100%">NASIR, AEJAZ</style></author><author><style face="normal" font="default" size="100%">MAYER, ZACHARY</style></author><author><style face="normal" font="default" size="100%">SHAHID, MOHAMMAD</style></author><author><style face="normal" font="default" size="100%">COPPOLA, DOMENICO</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Expression of DNA Mismatch Repair Proteins, PD1 and PDL1 in Barrett’s Neoplasia</style></title><secondary-title><style face="normal" font="default" size="100%">Cancer Genomics - Proteomics</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2022</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2022-03-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">145-150</style></pages><doi><style  face="normal" font="default" size="100%">10.21873/cgp.20310</style></doi><volume><style face="normal" font="default" size="100%">19</style></volume><issue><style face="normal" font="default" size="100%">2</style></issue><abstract><style  face="normal" font="default" size="100%">Background/Aim: Cancers with a microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) status respond to immune checkpoint inhibition (ICI). Regardless of the tumor type, MSI-H/dMMR status is a reliable biomarker for ICI responsiveness. This study aimed at determining the MSI-H status in precursor lesions to esophageal adenocarcinoma (EAC) such as Barrett’s esophagus (BE) and BE with either low-grade dysplasia (LGD) or high-grade dysplasia (HGD). Patients and Methods: We performed immunohistochemical staining (IHC) for PMS2, MSH6, PD1, and PD-L1. Results: All cases of BE (50), LGD (48), and HGD (50) had intact PMS2 and MSH6 nuclear expression; were negative for PD1; and had a PD-L1 combined positive score (CPS) score &lt;1. One EAC case (2%) was negative for PMS2 nuclear expression. One HGD case (2%) and two EAC cases (4%) were PD1 positive (CPS score &lt;1 applied to PD1). One EAC case (2%) had a CPS score &gt;1, and one EAC case (2%) was MSI-H. MSI-H tumors usually show PD-L1 expression, although the MSI-H EAC in this study had a PD-L1 CPS score of &lt;1. Conclusion: Further studies investigating EAC and its precursor lesions for PD1, PD-L1, and dMMR status may be informative regarding the immunogenicity of the evolution of EAC.</style></abstract></record></records></xml>