title: Galectin-4 expression in carcinoid tumors.
abstract: Galectins (Gal) are an evolutionarily conserved family of 15 carbohydrate-binding proteins (lectins) that are widely distributed in normal and neoplastic cells in a wide range of organisms. They have roles in inflammation, cell adhesion, tumor progression, and metastasis. The function and distribution of Gal-3 and Gal-1 are well characterized, but less information is available about Gal-4. Recent studies have localized Gal-4 in the enterochromaffin cells of the porcine and murine small intestine. We examined the expression of Gal-4 in primary and metastatic human ileal carcinoid tumors as well as in carcinoid tumors of the stomach, lung, and rectum. A total of 44 primary and 42 ileal metastatic carcinoid tumors were examined by immunohistochemistry using tissue microarrays (TMA) with monoclonal antibodies to Gal-4, Gal-3, and Gal-1. Pulmonary (n = 7), rectal (n = 6), and gastric (n = 6) carcinoids were examined with larger tissue sections. A total of 18 pancreatic neuroendocrine tumors were also examined with larger tissue sections. Western blots of three ileal carcinoids were also done. Gal-4 was most highly expressed in the ileal carcinoids and the levels of expression tended to be higher in primary ileal carcinoids compared to the metastatic tumors (p = 0.069). All 18 pancreatic neuroendocrine tumors were negative for Gal-1, Gal-3, and Gal-4. Western blot showed a 32 kDa band for Gal-4 in the ileal carcinoids. Gal-3 and Gal-1 were not detected in the metastatic ileal carcinoids by Western blotting. Gastric carcinoids also expressed Gal-4, but very few pulmonary or rectal carcinoids were positive for Gal-4 (p = 0.002). Lower levels of Gal-1 and Gal-3 expression were present in ileal carcinoids compared to primary pulmonary and rectal tumors. These results show a differential distribution of Gal-4 in carcinoid tumors in different locations of the gastrointestinal tract and the lungs.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
authors.forename: Kandelaria M
authors.initials: KM
authors.lastname: Rumilla
authors.forename: Lori A
authors.initials: LA
authors.lastname: Erickson
authors.forename: Alan K
authors.initials: AK
authors.lastname: Erickson
authors.forename: Ricardo V
authors.initials: RV
authors.lastname: Lloyd
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D015153:Blotting, Western; D002276:Carcinoid Tumor / Q000378:metabolism*; D037483:Galectin 1 / Q000096:biosynthesis; D037502:Galectin 3 / Q000096:biosynthesis; D037541:Galectin 4 / Q000096:biosynthesis*; D006801:Humans; D007078:Ileal Neoplasms / Q000378:metabolism; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000378:metabolism; D012004:Rectal Neoplasms / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D037483:Galectin 1; D037502:Galectin 3; D037541:Galectin 4