Supplementary Figure 2.

Distinct gland types within biopsy specimens. (A) An H&E of a biopsy specimen displaying glandular architecture. (B, C) Double IHC for MUC2 (AP-blue) + MUC5AC (DAB-brown) and HD6 (AP-blue) + MUC6 (brown), respectively. (Ai, Bi, Ci) Higher-power views of a single mature intestinal gland that is HD6⁺ (∗), where all other glands are specialized, and HD5^– with gland bases is evidenced by MUC6 staining. (D) A second biopsy specimen shows glandular architecture with a gastric phenotype (H&E). (E) Double IHC for H⁺K⁺ATPase (DAB-brown) and pepsinogen (AP-blue) shows 2 areas: area 1 is positive for both markers and is therefore an atrophic corpus phenotype with both parietal and chief cells present (E and Ei), whereas area 2 only shows positivity for H⁺K⁺ATPase parietal cells (DAB-brown) and is therefore oxyntocardiac (E and Eii). (F) MUC5AC (DAB-brown) + MUC2 (AP-blue) IHC did not show the presence of goblet cells in this biopsy.