In both the SPOTLIGHT and GLOW clinical trials, the prevalence of CLDN18.2-positive cancer was 38.4%.5,6 In the SPOTLIGHT trial, 42% of HER2-negative patients showed CLDN18.2-positive status.6 However, single-institution studies have reported CLDN18.2 prevalence rates of 14%–88% owing to various testing protocols and interpretations of CLDN18.2 immunohistochemistry (IHC).8–21 To date, there are no comprehensive real-world CLDN18.2 biomarker data that could help identify patients who may benefit from treatment with zolbetuximab or other targeted therapies. Here, CLDN18 is linked to cancer.