Preoperative Biomarkers in Gastro-oesophageal Adenocarcinoma

Advances in sequencing technology have enabled characterization of molecular pathways of tumorigenesis for esophageal cancer and the development of efficacious targeted therapies. Routine preoperative biomarker assessment of esophageal adenocarcinoma is offered to identify the cohort of patients who respond favorably to the targeted therapies presently approved for the treatment of this cancer: HER2 monoclonal antibodies such as trastuzumab and PD-1/PD-L1 check point inhibitors (e.g., pembrolizumab, nivolumab, and dostarlimab). There are three molecular biomarkers which are regularly (routinely in the case of HER-2) utilized in esophageal adenocarcinoma to predict a response to targeted therapies: HER2 positivity for trastuzumab, and microsatellite instability/mismatch repair (MSI/MMR) status and PD-L1 expression for pembrolizumab.