Although tumor heterogeneity of FGFR2 expression is highly prevalent and presents a limitation for screening accuracy [20], it can potentially be overcome using ctDNA sequencing in liquid biopsy, as this technique successfully identified FGFR2-positive cases that were negative on biopsy (7.7% (28/365) with ctDNA sequencing vs. 2.6%, 3.4%, and 4.4% with tissue analysis, as described in the publicly available tissue-based databases: the GI-SCREEN studies, The Cancer Genome Atlas (TCGA), and Memorial Sloan Kettering Cancer Center (MSKCC) [29]. The gene discussed is FGFR2; the disease is neoplasm.