SNFGE SNFGE
 
Thématique :
- Pancréas/Voies biliaires
Originalité :
Intermédiaire
Solidité :
A confirmer
Doit faire évoluer notre pratique :
Pas encore
 
 
Nom du veilleur :
Docteur Marine CAMUS DUBOC
Coup de coeur :
 
 
Gastroenterology
  2019/02  
 
  2019 Feb;156(3):647-661.e2.  
  doi: 10.1053/j.gastro.2018.10.029  
 
  Pathways of Progression From Intraductal Papillary Mucinous Neoplasm to Pancreatic Ductal Adenocarcinoma Based on Molecular Features.  
 
  Omori Y, Ono Y, Tanino M, Karasaki H, Yamaguchi H, Furukawa T, Enomoto K, Ueda J, Sumi A, Katayama J, Muraki M, Taniue K, Takahashi K, Ambo Y, Shinohara T, Nishihara H, Sasajima J, Maguchi H, Mizukami Y, Okumura T, Tanaka S  
  https://www.ncbi.nlm.nih.gov/pubmed/30342036  
 
 

Abstract

BACKGROUND & AIMS:

Intraductal papillary mucinous neoplasms (IPMNs) are regarded as precursors of pancreatic ductal adenocarcinomas (PDAs), but little is known about the mechanism of progression. This makes it challenging to assess cancer risk in patients with IPMNs. We investigated associations of IPMNs with concurrent PDAs by genetic and histologic analyses.

METHODS:

We obtained 30 pancreatic tissues with concurrent PDAs and IPMNs, and 168 lesions, including incipient foci, were mapped, microdissected, and analyzed for mutations in 18 pancreatic cancer-associated genes and expression of tumor suppressors.

RESULTS:

We determined the clonal relatedness of lesions, based on driver mutations shared by PDAs and concurrent IPMNs, and classified the lesions into 3 subtypes. Twelve PDAs contained driver mutations shared by all concurrent IPMNs, which we called the sequential subtype. This subset was characterized by less diversity in incipient foci with frequent GNAS mutations. Eleven PDAs contained some driver mutations that were shared with concurrent IPMNs, which we called the branch-off subtype. In this subtype, PDAs and IPMNs had identical KRAS mutations but different GNAS mutations, although the lesions were adjacent. Whole-exome sequencing and methylation analysis of these lesions indicated clonal origin with later divergence. Ten PDAs had driver mutations not found in concurrent IPMNs, called the de novo subtype. Expression profiles of TP53 and SMAD4 increased our ability to differentiate these subtypes compared with sequencing data alone. The branch-off and de novo subtypes had substantial heterogeneity among early clones, such as differences in KRAS mutations. Patients with PDAs of the branch-off subtype had a longer times of disease-free survival than patients with PDAs of the de novo or the sequential subtypes.

CONCLUSIONS:

Detailed histologic and genetic analysis of PDAs and concurrent IPMNs identified 3 different pathways by which IPMNs progress to PDAs-we call these the sequential, branch-off, and de novo subtypes. Subtypes might be associated with clinical and pathologic features and be used to select surveillance programs for patients with IPMNs.

 

 
Question posée
 
Les mécanismes par lesquels les TIPMP évoluent vers un adénocarcinome canalaire pancréatique ne sont pas clairs. Cette étude a comparé des modèles de mutations génétiques entre les TIPMP et les adénocarcinomes (ADK) concomitants identifiés sur une même pièce opératoire (30 pièces opératoires - analyse de l’expression de 18 gènes associés au cancer du pancréas ou gènes suppresseurs de tumeurs).
 
Question posée
 
Les auteurs ont constaté que les TIPMP progressaient vers des adénocarcinomes via trois voies différentes : une voie séquentielle (mêmes mutations génétiques sur la TIPMP et l’ADK concomitant, essentiellement dû gène GNAS), une voie ramifiée (mêmes mutations génétiques de Kras mais différentes pour GNAS), et une voie de novo (mutations différentes pour Kras).
 
Commentaires

Les informations sur les voies par lesquelles les TIPMP progressent vers un ADK sont essentielles afin de mieux comprendre la physiopathologie carcinologique des TIPMP, et à terme les utiliser dans la conception de programme de surveillance pour les patients.

 
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