Fig 2: Double immunofluorescence staining of delta‐like 3 (DLL3) and CHGA in normal stomach and duodenum. DLL3 and CHGA in the stomach (A) and duodenum (B). DLL3 is dyed green and CHGA red. Nuclei are dyed blue with DAPI. Lower panel, merged images, showing yellow fluorescence for co‐occurring antigens. White box: enlarged area of merged view. Scale bar: 10 μm

Fig 3: Delta‐like 3 (DLL3) expression in chromogranin A (CHGA)‐positive gastric cancer specimens. A, The expression of DLL3 in 4 CHGA‐positive gastric cancer tissue specimens and 2 GI‐MANEC tissue specimens. Detailed clinical information for each patient is shown in Table 1. Scale bar: 50 μm. B, The expression of DLL3 in a CHGA‐positive area of the serial tissue sections of gastric cancer specimens. The representative images of areas of cases 1 and 2 (case 1‐1 and case 2‐1) are shown. Left panel, the expression of DLL3; right panel, expression of CHGA; red box, the enlarged area. The lower panel shows the enlarged versions of each image. Scale bar: 100 μm

Fig 4: The expression levels of delta‐like 3 (DLL3) in gastrointestinal‐neuroendocrine carcinoma ECC cell lines. A, DLL3 mRNA expression in ECC cell lines, compared with that in other cancer cell lines (hepatocellular carcinoma cells, HepG2; and colon cancer cells, DLD‐1). The ratio of DLL3 expression to that of HepG2 was calculated, and the values are shown with HepG2 normalized to 1.0. Results are presented as the mean ± SD; ***P < 0.001. B, The protein expression level of DLL3 in these cells

Fig 5: The pattern of delta‐like 3 (DLL3) expression in the gastrointestinal (GI) tract. DLL3 expression in the stomach (A), duodenum (B), jejunum (C), ileum (D) and rectum (E). Left panel, the expression of DLL3; right panel, expression of IgG‐rabbit used as a negative control. F, The enlarged view of (A) and (E). Scale bar: 50 μm