Chitinase 3-like 1 (CHI3L1), one of mammalian members of the chitinase family, is expressed in several types of human cancer, and elevated serum level of CHI3L1 is suggested to be a biomarker of poor prognosis in advanced cancer patients. However, the overall biological function of CHI3L1 in human cancers still remains unknown. Studies were performed to characterize the role of CHI3L1 in cancer pathophysiology utilizing human colorectal cancer samples and human cell lines. Plasma protein and tissue mRNA expression levels of CHI3L1 in colorectal cancer were strongly upregulated. Immunohistochemical analysis showed that CHI3L1 was expressed in cancer cells and CHI3L1 expression had a significant association with the number of infiltrated macrophages and microvessel density. By utilizing trans-well migration and tube formation assays, overexpression of CHI3L1 in SW480 cells (human colon cancer cells) enhanced the migration of THP-1 cells (human macrophage cells) and HUVECs (human endothelial cells), and the tube formation of HUVECs. The knockdown of CHI3L1 by RNA interference or the neutralization of CHI3L1 by anti-CHI3L1 antibody displayed strong suppression of CHI3L1-induced migration and tube formation. Cell proliferation assay showed that CHI3L1 overexpression significantly enhanced the proliferation of SW480 cells. ELISA analysis showed that CHI3L1 increased the secretion of inflammatory chemokines, IL-8 and MCP-1, from SW480 cells through mitogen-activated protein kinase (MAPK) signaling pathway. Both neutralization of IL-8 or MCP-1 and inhibition or knockdown of MAPK in SW480 cells significantly inhibited CHI3L1-induced migration and tube formation. In a xenograft mouse model, overexpression of CHI3L1 in HCT116 cells (human colon cancer cells) enhanced the tumor growth as well as macrophage infiltration and microvessel density. In conclusion, CHI3L1 expressed in colon cancer cells promotes cancer cell proliferation, macrophage recruitment and angiogenesis. Thus, the inhibition of CHI3L1 activity may be a novel therapeutic strategy for human colorectal cancer.

We report a case of immunoglobulin G4 (IgG4)-related sclerosing disease involving the pancreas, liver and salivary glands. Massive infiltration of IgG4-expressing plasma cells was seen in the liver and submandibular lymph nodes. Interestingly, accumulation of IgG4-expressing plasma cells was also seen in the colon and terminal ileum. Peripheral blood mononuclear cells (PBMCs) isolated from this patient exhibited enhanced production of IgG4 and interleukin-10 upon stimulation with Toll-like receptor (TLR) ligands as compared with those from a healthy control. In contrast, production of tumour necrosis factor alpha and interferon gamma by PBMCs from this patient was markedly reduced. Since colonic mucosa is always exposed to TLR ligands derived from commensal organisms, the results of immunological studies suggest that enhanced T helper type 2 responses to intestinal microflora may underlie the immunopathogenesis in this patient with IgG4-related sclerosing disease.

Perivascular epithelioid cell (PEC) is a unique cell which expresses both myogenic and melanocytic markers, and forms PEComa. A 36-year-old woman presented with a 35 mm-diameter liver tumor. MRI showed poor fat component in the tumor. Contrast-enhanced ultrasonography using the newly developed enhancing reagent, Sonazoid, clearly demonstrated early-phase enhancement of the tumor and rapid drainage of the reagent to veins, suggesting a PEComa. Lateral segmentectomy of the liver was performed. Histologically, epithelioid tumor cells around the vessels were immunostained with both HMB-45 and alpha-smooth muscle actin, confirming the diagnosis of PEComa. No recurrence has been found for 18 months following the operation.

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A 59-year-old man treated with 5-fluorouracil and cisplatin for advanced oesophageal cancer presented abnormal behaviour and subsequently developed impairment of cognitive function, dysphagia and dysarthria on the fifth day of the treatment. Although brain computed tomography revealed no abnormal findings, brain magnetic resonance imaging using diffusion-weighted imaging clearly revealed the presence of a high signal intensity in the deep white matter of the bilateral cerebral hemispheres, including the corpus callosum symmetrically. A diagnosis of acute leukoencephalopathy was reached based on these findings. His clinical symptoms normalized four days after the discontinuation of the chemotherapy. Improvement in magnetic resonance imaging findings was delayed compared with that of clinical symptoms; however, the high signal intensity detected in the deep white matter had disappeared completely five months after the onset of symptoms. Early detection of drug-induced leukoencephalopathy is important as the clinical symptoms can be reversed by early discontinuation of the causative drug. Diffusion-weighted magnetic resonance imaging is a useful modality for the early detection and definitive diagnosis of this characteristic encephalopathy.