Significance of aberrant (cytoplasmic/nuclear) expression of beta-catenin in pancreatoblastoma.

Abstract

This study concerns the significance of aberrant (nuclear/cytoplasmic) expression of beta-catenin in pancreatoblastoma (PBL). On immunohistochemistry, all seven PBLs examined showed nuclear/cytoplasmic expression of beta-catenin, predominantly in the squamoid corpuscles (SCs). In areas with acinar/ductular differentiation, few tumour cells displayed nuclear/cytoplasmic expression of beta-catenin and more than half of the tumour cells showed membranous expression. Two out of five (40%) tumours examined showed missense mutations in codons 33 and 37 of exon 3 of the beta-catenin gene. No mutation of the adenomatous polyposis coli (APC) gene was detected in two of the remaining three tumours. Amplifiable DNA for APC analysis was not obtained from the one other tumour. Immunoreactivity for cyclin D1, one of the nuclear targets of beta-catenin, was found predominantly in the SCs of the seven tumours. In contrast, the Ki-67 labelling index was 2-4% (median 3%) in the SCs and 8-18% (median 12%) in the other areas, indicating a negative correlation with nuclear cyclin D1 reactivity. These results imply that in PBLs, nuclear/cytoplasmic accumulation of beta-catenin and overexpression of its target gene cyclin D1 are not associated with the induction of tumour cell proliferation. Nuclear/cytoplasmic accumulation of beta-catenin may be related to the morphogenesis of the SCs that are considered most characteristic for PBL.

• Authors: Yukichi Tanaka, Keisuke Kato, Kenji Notohara, Yukio Nakatani, Tetsumi Miyake, Rieko Ijiri, Shigeo Nishimata, Yuji Ishida, Hisato Kigasawa, Yokatsu Ohama, Choutatsu Tsukayama, Yasutsugu Kobayashi, Hiroshi Horie
• Journal: The Journal of pathology (J Pathol) Vol. 199 Issue 2 Pg. 185-90 (Feb 2003) ISSN: 0022-3417 [Print] England
• PMID: 12533831 (Publication Type: Journal Article)
• Copyright: Copyright 2002 John Wiley & Sons, Ltd.

Chemical References

• CTNNB1 protein, human
• Cytoskeletal Proteins
• DNA, Neoplasm
• Neoplasm Proteins
• Trans-Activators
• beta Catenin
• Cyclin D1

Topics

• Child
• Child, Preschool
• Cyclin D1 (analysis)
• Cytoskeletal Proteins (analysis)
• DNA, Neoplasm (analysis)
• Female
• Genes, APC
• Humans
• Immunohistochemistry (methods)
• Male
• Mutation
• Neoplasm Proteins (analysis)
• Pancreatic Neoplasms (genetics, pathology)
• Sequence Analysis, DNA (methods)
• Trans-Activators (analysis)
• beta Catenin