title: Expression pattern of keratin subclasses in pancreatoblastoma with special emphasis on squamoid corpuscles.
abstract: Expression patterns of keratins (K), both simple epithelia-type (K7, K8, K18, K19) and complex/stratified epithelia-type (K1, K4, K5/6, K10, K13, K14, K15, K16, K17), and epithelial membrane antigen (EMA) were immunohistochemically studied in six pancreatoblastomas (PBL). In all six tumors, areas with overt acinar differentiation (AA), solid areas without any specific differentiation (SO), and squamoid corpuscles (SC) were diffusely positive for K8, K18, and K19. The AA and SO in all the tumors were diffusely positive for K7, but the SC were negative or displayed only scattered reactivity for K7. In three tumors, the AA and the SC showed scattered reactivity for K5/6. No reactivity for other complex/stratified epithelia-type K was found in any of the examined tumor. All tumors were reactive for EMA with consistent predominancy in the SC. Ultrastructurally, well-developed desmosome-tonofilament complexes were only partially observed in tumor cells comprising the SC. These results implied that (i) the SC usually lack a character of complete squamous metaplasia; and (ii) the SC have a characteristic phenotype (K8/K18/K19/EMA-positive, K7-negative or scatteredly positive) that can potentially be useful to delineate the SC in PBL.
authors.affiliation: Department of Pediatrics, Tokyo Medical University, Tokyo.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Nishimata
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kato
authors.forename: Mio
authors.initials: M
authors.lastname: Tanaka
authors.forename: Rieko
authors.initials: R
authors.lastname: Ijiri
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Toyoda
authors.forename: Hisato
authors.initials: H
authors.lastname: Kigasawa
authors.forename: Yokatsu
authors.initials: Y
authors.lastname: Ohama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakatani
authors.forename: Kenji
authors.initials: K
authors.lastname: Notohara
authors.forename: Yasutsugu
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Horie
authors.forename: Akinori
authors.initials: A
authors.lastname: Hoshika
authors.forename: Yukichi
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000096:biosynthesis*; D008297:Male; D008854:Microscopy, Electron; D018396:Mucin-1 / Q000032:analysis; D010179:Pancreas / Q000737:chemistry / Q000473:pathology / Q000648:ultrastructure; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D018396:Mucin-1; D007633:Keratins