PT  - JOURNAL ARTICLE
AU  - JAMES J. SALLER
AU  - LINDA B. MORA
AU  - AEJAZ NASIR
AU  - ZACHARY MAYER
AU  - MOHAMMAD SHAHID
AU  - DOMENICO COPPOLA
TI  - Expression of DNA Mismatch Repair Proteins, PD1 and PDL1 in Barrett’s Neoplasia
AID  - 10.21873/cgp.20310
DP  - 2022 Mar 01
TA  - Cancer Genomics - Proteomics
PG  - 145--150
VI  - 19
IP  - 2
4099  - http://cgp.iiarjournals.org/content/19/2/145.short
4100  - http://cgp.iiarjournals.org/content/19/2/145.full
SO  - Cancer Genomics Proteomics2022 Mar 01; 19
AB  - 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 <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 <1 applied to PD1). One EAC case (2%) had a CPS score >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 <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.