A Space-Time Continuum for Immunotherapy Biomarkers in Gastroesophageal Cancer?

In an annotated series of gastroesophageal adenocarcinomas differences in PD-L1 expression and tumor mutation burden occur between both paired contemporaneous primary and metastatic biopsies and pre/posttreatment samples. This work has implications for optimizing patient selection, serial testing, need for mechanistic understanding, and may underlie variable responses to checkpoint inhibitors in gastroesophageal cancers.See related article by Zhou et al., p. 6453.