Prithwish Ghosh, MBBS1, Bhaskar Roy1, Bryan Linn1, Tiffany L. Mangels-Dick1, Yuri Hanada, MD1, Kenneth K. Wang, MD, FACG2; 1Mayo Clinic, Rochester, MN; 2Mayo Clinic College of Medicine, Rochester, MN
Introduction: Esophageal adenocarcinoma has a poor prognosis if discovered in advanced stage. At the current time,endoscopic therapy is used for treatment of Barrett's esophagus which is the only known precursor for esophageal carcinoma.Endoscopic therapy for early esophageal cancer is also performed but there is the potential of metastatic disease with even at the T1 stage. The ability to use immune checkpoint inhibitors to treat this would be useful to prevent the need for chemotherapy or surgical resection. Although immunotherapy was disappointing for advanced metastatic esophageal cancer we assessed the presence of PDL1 in early cancers. Methods: ESD,EMR, or biopsy samples were taken from patients that previously consented to allow future use of their specimens.Samples from 15 patients with BE with LGD (5), HGD (5) and early EAC (5) were taken.These were patients that were diagnosed with BE previously and above the age of 18. They were given an unique coding identifier for this study and their information was de-identified when we recorded the data to maintain privacy.5 mm of tissue sections were immune stained using PD1 (Abcam,Cambridge,MA) and PDL1 ( Millipore, St.Louis, MO) markers and images were scanned using MoticEasyScan digital slide scanner (Motic,San Francisco, CA) and the average integrated intensity of positive signal was normalized against the total tissue area. Results: Positive intensity of the PD1 stained samples of all 15 patients for BE with LGD, BE with HGD and early stage EAC are 29.96±9.49, 46.26±19.78 and 39.53±31.46 respectively (Figure 1).The intensity was enumerated by combining the positive integrated intensity of the DAB signal, normalized by the total area of the tissue.Antibody was calibrated against the human tonsil tissue as positive control and no primary antibody as negative control.Positive intensity of the PDL1 stained samples of all 15 patients for BE with LGD, BE with HGD, and early stage EAC are 8.99±1.01, 9.31±0.31 and 9.48±0.15 respectively(Figure 2a and 2b). Discussion: From this study we saw PD 1 ligand expression is present on both low grade and high grade Barrett's tissue and early esophageal cancer.This may open up an opportunity in the treatment of Barrett's esophagus and early esophageal cancer.In patients with invasive disease that are poor surgical candidates,immune checkpoint inhibitors may offer an opportunity for therapy that is better tolerated than traditional chemotherapy and radiation.
Figure 1.Bar diagram of positive intensity of PD1 stained sample
Figure 2a.Bar diagram of positive intensity of PDL1 stained sample
Figure 2b. Expression of PDL1 marker on esophageal tissue section
Disclosures: Prithwish Ghosh indicated no relevant financial relationships. Bhaskar Roy indicated no relevant financial relationships. Bryan Linn indicated no relevant financial relationships. Tiffany Mangels-Dick indicated no relevant financial relationships. Yuri Hanada indicated no relevant financial relationships. Kenneth Wang indicated no relevant financial relationships.