This is further underscored by the extensive intratumoural heterogeneity in FGFR2b protein expression in GCs (55.5% of cases) [44], discordance in FGFR2 protein expression between primary and matched metastatic lymph node samples (28% of cases) [44], and the high false negative rates of detecting FGFR2 overexpression in a single tumour biopsy (up to 40% of cases), requiring increasing the number of diagnostic biopsies [95]. The gene discussed is FGFR2; the disease is neoplasm.