Pancreatic neuroendocrine carcinomas reveal a closer relationship to ductal adenocarcinomas than to neuroendocrine tumors G3

doi:10.1016/j.humpath.2018.03.018

Human Pathology

Volume 77, July 2018, Pages 70-79

https://doi.org/10.1016/j.humpath.2018.03.018 Get rights and content

Highlights

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Neuroendocrine carcinomas harbored TP53 and KRAS mutations.
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Neuroendocrine tumors G3 are genetically different.
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Most KRAS-positive carcinomas also expressed markers of ductal differentiation.
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Neuroendocrine carcinomas are related to pancreatic ductal adenocarcinomas.

Summary

Pancreatic neuroendocrine carcinoma is a rare aggressive tumor commonly harboring TP53 and RB1 alterations and lacking neuroendocrine-related genetic changes such as mutations in MEN1 and ATRX/DAXX. Little is known about its genetic profile with regard to that of pancreatic ductal adenocarcinoma. We therefore conducted a detailed genetic study in 12 pancreatic neuroendocrine carcinomas of large cell (n = 9) and small cell type (n = 3) using massive parallel sequencing applying a 409-gene panel on an Ion Torrent system. The genetic data were compared with known data of pancreatic ductal adenocarcinoma and correlated with exocrine lineage marker expression. A similar analysis was performed in 11 pancreatic neuroendocrine tumors G3. Neuroendocrine carcinomas harbored 63 somatic mutations in 45 different genes, affecting most commonly TP53 (8/12 cases), KRAS (5/12 cases), and RB1 (loss of expression with or without deletion in 4/12 cases). Five carcinomas had both TP53 and KRAS mutations. Neuroendocrine tumors G3 only shared singular mutations in 5 different genes with neuroendocrine carcinomas, including TP53, CDKN2A, ARID1A, LRP1B, and APC, affecting 5 different cases. Most KRAS-positive neuroendocrine carcinomas also expressed MUC1 (4/5) and carcinoembryonic antigen (3/5) as markers of ductal differentiation. Our data indicate that almost half of the pancreatic neuroendocrine carcinomas are genetically and phenotypically related to pancreatic ductal adenocarcinoma, and might therefore respond to chemotherapies targeting the latter carcinomas.

Introduction

The G3 category of the 2017 World Health Organization (WHO) classification of pancreatic neuroendocrine neoplasms defines tumors with a Ki-67 index greater than 20% that are either well or poorly differentiated. The well-differentiated neuroendocrine neoplasms are called neuroendocrine tumors G3, and the poorly differentiated ones are called neuroendocrine carcinomas, either of small cell or of large cell type [1]. Neuroendocrine tumors G3 often evolve from G1/2 tumors after metastasizing to the liver during the course of the disease, but can also present as primary tumor in the pancreas [1], [2]. They show an organoid solid or trabecular endocrine growth pattern, and usually express hormones and the somatostatin receptor 2A. In contrast, pancreatic neuroendocrine carcinomas display irregular sheets of cells or solid structures, either of small cell or of large cell cytology, and are rarely somatostatin receptor 2A and hormone positive. In addition, they commonly show an abnormal nuclear expression of p53 and Rb1 that is usually lacking in neuroendocrine tumors [2]. These data suggest that neuroendocrine tumors and neuroendocrine carcinomas may be fundamentally different neoplasms, a distinction that has a strong impact on treatment strategies [1], [3].

It is not known which cells give rise to neuroendocrine tumors and neuroendocrine carcinomas in the pancreas. Candidates are cells belonging to either the neuroendocrine or the ductal-acinar cell lineage. Although the neuroendocrine tumors may be related to the neuroendocrine cell lineage, the neuroendocrine carcinomas could derive from the neuroendocrine cell lineage, the ductal-acinar cell lineage, or a still uncommitted cell lineage. In view of these possibilities, it is of interest to see whether there is a genetic relationship between neuroendocrine carcinomas and conventional ductal adenocarcinomas. Such an assumption is fostered by data from genetic studies in colorectal neuroendocrine carcinomas, suggesting that these special neoplasms are closely related to conventional colorectal adenocarcinomas [4], [5], [6], [7].

In this study, we conducted a detailed molecular profiling of a relatively large cohort of these exceedingly rare neuroendocrine carcinomas of the pancreas and correlated the results with an immunohistochemical panel including exocrine lineage markers such as MUC1, MUC2, and carcinoembryonic antigen (CEA) [8]. The following questions were addressed: First, are neuroendocrine carcinomas genetically related to ductal adenocarcinomas? Second, are there also genetic similarities between neuroendocrine tumors G3 and ductal adenocarcinomas? Third, are neuroendocrine carcinomas homogeneous in their genetic profile or are there differences between small cell and large cell types?

Section snippets

Tissue recruitment

Formalin-fixed and paraffin embedded tissue blocks from 23 surgical resection specimens of primary pancreatic neuroendocrine neoplasms (12 neuroendocrine carcinomas and 11 neuroendocrine tumors G3) were retrieved from the files of the Consultation Center for Pancreatic and Endocrine Tumors, Technical University of Munich, as well as from the Department of Pathology, Technical University of Munich, Germany. Clinicopathological information was obtained from the medical charts and pathology

Clinical data and histologic features

Pancreatic neuroendocrine carcinomas were diagnosed in 12 patients, with a mean age at diagnosis of 55.4 years and a female-to-male ratio of 9:3 (Table 1). Nine of 12 tumors were subclassified as large cell neuroendocrine carcinomas and 3 of 12 as small cell neuroendocrine carcinomas (Tables 1 and 2). One of the large cell tumors contained a glandular, slightly PAS-positive component that accounted for more than 30% of all neoplastic cells and was therefore classified as a mixed neuroendocrine

Discussion

The data of our study support the notion that poorly differentiated pancreatic neuroendocrine neoplasms (neuroendocrine carcinomas) represent a tumor group that fundamentally differs from well-differentiated pancreatic neuroendocrine neoplasms (neuroendocrine tumors). Aside from their clinicopathological features (ie, aggressiveness, histologic architecture, hormone production, and syndromes), the 2 tumor groups are distinguished by their different genetic profiles that focus on genetic

Supplementary Data

The following are the supplementary data related to this article.

. Somatic mutations in neuroendocrine carcinomas and neuroendocrine tumors G3.

. Copy number variations in neuroendocrine carcinomas and neuroendocrine tumors G3.

Acknowledgments

We are grateful to Petra Meyer, the Comparative Experimental Pathology and the Next Generation Sequencing Core Facility for excellent technical assistance.

Statement of author contributions

B. K., M. J., N. P., and G. K. collected data, designed the study, conceived and carried out experiments, analyzed data, and wrote the manuscript. K. S. conceived and carried out experiments and analyzed data. A. M. S., A. K., B. S., G. Z., and W. W. collected and analyzed data. All authors approved the final version of the manuscript.

References (22)

B. Konukiewitz et al.
Somatostatin receptor expression related to TP53 and RB1 alterations in pancreatic and extrapancreatic neuroendocrine neoplasms with a Ki67-index above 20%
Mod Pathol
(2017)
M. Jesinghaus et al.
Colorectal mixed adenoneuroendocrine carcinomas and neuroendocrine carcinomas are genetically closely related to colorectal adenocarcinomas
Mod Pathol
(2017)
C. Woischke et al.
In-depth mutational analyses of colorectal neuroendocrine carcinomas with adenoma or adenocarcinoma components
Mod Pathol
(2017)
V. Endris et al.
Molecular diagnostic profiling of lung cancer specimens with a semiconductor-based massive parallel sequencing approach: feasibility, costs, and performance compared with conventional sequencing
J Mol Diagn
(2013)
R.V. Lloyd et al.
WHO classification of tumours of endocrine organs
(2017)
O. Basturk et al.
The high-grade (WHO G3) pancreatic neuroendocrine tumor category is morphologically and biologically heterogenous and includes both well differentiated and poorly differentiated neoplasms
Am J Surg Pathol
(2015)
L.H. Tang et al.
Well-differentiated neuroendocrine tumors with a morphologically apparent high-grade component: a pathway distinct from poorly differentiated neuroendocrine carcinomas
Clin Cancer Res
(2016)
A.O. Vortmeyer et al.
Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas
J Natl Cancer Inst
(1997)
R.H. Hruban et al.
Ductal adenocarcinoma of the pancreas
N. Pfarr et al.
Mutational profiles of Brenner tumors show distinctive features uncoupling urothelial carcinomas and ovarian carcinoma with transitional cell histology
Genes Chromosomes Cancer
(2017)

K. Wang et al.

ANNOVAR: functional annotation of genetic variants from high-throughput sequencing data

Nucleic Acids Res

(2010)

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Citation Excerpt :
Instead, mutation in TP53 and/or abnormal immunolabeling of p53 protein were identified in 56–95% of PanNECs (Tang et al., 2016a, 2016b; Yachida et al., 2012; Konukiewitz et al., 2018). Konukiewitz et al. and Yachida et al. reported that these mutations were missense, nonsense, or frameshift mutations (Yachida et al., 2012; Konukiewitz et al., 2018). In several series of PanNETs, no p53 abnormal protein expression was noted (Jiao et al., 2011; Tang et al., 2016a, 2016b; Lam and Lo, 1998).
Pancreatic neuroendocrine neoplasms (PanNENs) are the neuroendocrine neoplasms with greatest rate of increase in incidence. Approximately 10% of PanNENs arise as inherited tumour syndromes which include multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 4, von Hippel–Lindau syndrome, neurofibromatosis type1, tuberous sclerosis complex 1/2, Cowden syndrome, and Glucagon cell hyperplasia and neoplasia as well as familial insulinomatosis. In sporadic PanNENs, driver mutations in MEN1, DAXX/ATRX and mTOR pathway genes are associated with development and progression in pancreatic neuroendocrine tumours. The other changes are in VEGF pathway, Notch pathway, germline mutations in MUTYH, CHEK2, BRCA2, PHLDA3 as well as other genetic alterations. On the other hand, pancreatic neuroendocrine carcinomas share similar genetic alterations with ductal adenocarcinomas, e.g., TP53, RB1 or KRAS. In addition, microRNA and changes in immune microenvironment were noted in PanNENs. Updates on these genetic knowledges contribute to the development of management strategies for patients with PanNENs.

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^☆: Disclosures: There is no conflict of interest to declare. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

¹: Shared first authorship.

²: Member of the German Cancer Consortium (DKTK).

³: Shared last authorship.

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Original contributionPancreatic neuroendocrine carcinomas reveal a closer relationship to ductal adenocarcinomas than to neuroendocrine tumors G3☆

Highlights

Summary

Introduction

Section snippets

Tissue recruitment

Clinical data and histologic features

Discussion

Supplementary Data

Acknowledgments

Statement of author contributions

Mod Pathol

Mod Pathol

Mod Pathol

J Mol Diagn

WHO classification of tumours of endocrine organs

The high-grade (WHO G3) pancreatic neuroendocrine tumor category is morphologically and biologically heterogenous and includes both well differentiated and poorly differentiated neoplasms

Am J Surg Pathol

Well-differentiated neuroendocrine tumors with a morphologically apparent high-grade component: a pathway distinct from poorly differentiated neuroendocrine carcinomas

Clin Cancer Res

Concordance of genetic alterations in poorly differentiated colorectal neuroendocrine carcinomas and associated adenocarcinomas

J Natl Cancer Inst

Ductal adenocarcinoma of the pancreas

Mutational profiles of Brenner tumors show distinctive features uncoupling urothelial carcinomas and ovarian carcinoma with transitional cell histology

Genes Chromosomes Cancer

ANNOVAR: functional annotation of genetic variants from high-throughput sequencing data

Nucleic Acids Res

Original contribution
Pancreatic neuroendocrine carcinomas reveal a closer relationship to ductal adenocarcinomas than to neuroendocrine tumors G3☆