Genetic alterations of the transforming growth factor beta receptor genes in pancreatic and biliary adenocarcinomas

Cancer Res. 1998 Dec 1;58(23):5329-32.

Abstract

Transforming growth factor beta (TGF-beta) is an extracellular ligand that binds to a heterodimeric receptor, initiating signals that regulate growth, differentiation, and apoptosis. Many cancers, including pancreatic cancer, harbor defects in TGF-beta signaling and are resistant to TGF-beta-mediated growth suppression. Genetic alterations of DPC4, which encodes a DNA binding protein that is a downstream component of the pathway, most frequently occur in pancreatic and biliary carcinomas. We searched for other targets of mutation of the TGF-beta pathway in these cancers. We report somatic alterations of the TGF-beta type I receptor gene ALK-5. Homozygous deletions of ALK-5 were identified in 1 of 97 pancreatic and 1 of 12 biliary adenocarcinomas. A germ-line variant of ALK-5, presumably a polymorphism, was identified, but no somatic intragenic mutations were identified upon sequencing of all coding regions of ALK-5. Somatic alterations of the TGF-beta type II receptor gene (TGFBR2) were identified in 4 of 97 (4.1%) pancreas cancers, including a homozygous deletion in a replication error-negative cancer and three homozygous frameshift mutations of the poly(A) tract of the TGF-beta type II receptor in replication error-positive cancers. We also studied other related type I receptors of the TGF-beta superfamily. In a panel of pancreas cancers preselected for loss of heterozygosity at the ALK-1 locus, sequencing of all coding exons of the ALK-1 gene revealed no alterations. No homozygous deletions were detected in the ALK-1, ALK-2, ALK-3, or ALK-6 genes in a panel of 86 pancreatic cancer xenografts and 11 pancreatic cancer and 22 breast cancer cell lines. The rate of genetic inactivation of TGF-beta pathway members was determined in 45 pancreatic cancers. Eighty-two % of these pancreatic cancers had genetic inactivation of the DPC4, p15, ALK-5, or TGFBR2 genes. Our results indicate that the TGF-beta type I and type II receptor genes are selective targets of genetic inactivation in pancreatic and biliary cancers.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Activin Receptors
  • Adenocarcinoma / genetics*
  • Adenocarcinoma / ultrastructure
  • Aged
  • Biliary Tract Neoplasms / genetics*
  • Biliary Tract Neoplasms / ultrastructure
  • Carcinoma, Ductal, Breast / genetics*
  • Carcinoma, Ductal, Breast / ultrastructure
  • DNA-Binding Proteins / genetics
  • Female
  • Genes, p16
  • Humans
  • Loss of Heterozygosity
  • Male
  • Middle Aged
  • Mutation
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / ultrastructure
  • Protein Serine-Threonine Kinases / genetics
  • Receptor, Transforming Growth Factor-beta Type II
  • Receptors, Transforming Growth Factor beta / genetics*
  • Smad4 Protein
  • Trans-Activators / genetics
  • Transforming Growth Factor beta / genetics

Substances

  • DNA-Binding Proteins
  • Receptors, Transforming Growth Factor beta
  • SMAD4 protein, human
  • Smad4 Protein
  • Trans-Activators
  • Transforming Growth Factor beta
  • Protein Serine-Threonine Kinases
  • Activin Receptors
  • Receptor, Transforming Growth Factor-beta Type II