Identification and characterization of a novel adenomatous polyposis coli mutation in adult pancreatoblastoma.

Shigeo Yamaguchi,Yuki Izumi,Takao Sekiya,Min Han,Yuki Fukumura,Tomomi Akita,Hideki Yamaguchi,Tomoaki Fujii,Chikamasa Yamashita,Shunsuke Kato

doi:10.18632/oncotarget.24017

Shigeo Yamaguchi, Yuki Izumi + Show 8 more

Open Access

https://doi.org/10.18632/oncotarget.24017

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Abstract

During next generation sequencing (NGS) analysis, many missense mutations were found in a well-known oncogene, many of which were variant of uncertain significance mutations. We recently treated an adult patient with pancreatoblastoma by chemotherapy. Using an NGS cancer panel, we found a previously unreported missense mutation in the 1835 codon of the adenomatous polyposis coli (APC) gene. We also found a heterogeneous mutation in the 1835 codon of the APC gene in the patient's germline by Sanger sequencing. Although this patient did not have a history of familial adenomatous polyposis, functional analysis suggested the R1835G mutant APC showed attenuated repression of Wnt/β-catenin signaling activity. This is the first report showing a novel APC missense mutation involved in the onset of adult pancreatoblastoma.

Highlights

Pancreatoblastoma is a rare malignant epithelial neoplasm of the pancreas with multiple lines of differentiation, including acinar differentiation and squamoid nests
We confirmed the mutation of the adenomatous polyposis coli (APC) gene by Sanger sequencing (Figure 2A) and the expression of APC protein by immunohistochemical staining (Figure 1G) in tumor tissue samples from the patient
After obtaining written informed consent from the patient, we analyzed her germ line APC gene from her saliva and found a heterogeneous mutation in the 1835 codon of the APC gene (Figure 2A). These data suggest that a loss of heterozygosity (LOH) of the APC gene occurred in the tumor, and the products of the APC missense mutation took part in tumorigenesis

Summary

Introduction

Pancreatoblastoma is a rare malignant epithelial neoplasm of the pancreas with multiple lines of differentiation, including acinar differentiation and squamoid nests. Less frequently, this tumor may exhibit endocrine and ductal differentiation and may contain a distinct mesenchymal component [1]. Pancreatoblastoma usually occurs in childhood and is the most prevalent malignant pancreatic tumor in the first decade of life [2]. It can be encountered in adults, such cases are so rare that fewer than fifty cases have been reported to date [3]. There have been only a few reports on the molecular features of pancreatoblastoma

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