Figure 3.

CHI3L1 is expressed by unique type of cells in colons from patients with UC who have dysplasia. A and B: A colonic biopsy specimen obtained from a patient with UC who has high-grade dysplasia is shown (H&E stain, A: objective, 10×, B: objective, 40×). The area indicted by a rectangle in A corresponds to B. C and D: Serial sections of the same case were stained with rabbit anti-CHI3L1 antibody (objective, 40×). Arrows show triangular-shaped cells (C) and Paneth cells (D) stained positively with CHI3L1. E and F: Colonic biopsies from patients with UC who had remote dysplasia were stained with anti-CHI3L1 antibody (objective, 40×). Arrows demonstrate scattered (F) and clustered (E) neuroendocrine-like cells in colonic crypts with intense CHI3L-1 expression. G–L: H&E sections of a colonic resection (G) and a liver biopsy (J and K) from a patient with UC in whom colonic mucinous adenocarcinoma (not shown) and high-grade neuroendocrine carcinoma (G) developed, followed by liver metastasis (J and K). The area indicated by a rectangle in J corresponds to K. In J, the hepatic parenchyma is completely replaced by neuroendocrine carcinoma (arrows) and desmoplastic stroma (G: objective, 10×; J: objective, 4×; and K: objective, 40×). H, I, and L: The area indicated by a rectangle in H corresponds to I. Serial sections stained with anti-CHI3L1 antibody show diffuse CHI3L-1 expression in tumor cells (I and L). Arrows in I demonstrate presumable neuroendocrine granules with strong CHI3L1 staining (H: objective, 20×; I: objective, 60×; and L: objective, 40×).