Fig. 1.

a CLDN18 expression in normal gastric glands. b High CDLN18 expression in a gastric cancer (the adenocarcinoma is covered by normal gastric glands, which show an intense CLD18 positivity). c Moderate CLDN18 expression in cancer glands. d Low CLDN18 expression. e A negative CDLN18 tumour near to positive CLDN18 normal gastric glands. f Low CLDN18 expression in signet-ring cell carcinoma surrounding a positive single normal gastric gland. g CDLN18 intratumour variability. h Moderate-to-strong nuclear and cytoplasmic CLDN18 positivity. (Original magnifications ×20; scale bar 100 µm)