Novel mutations in the polyadenine tract of the transforming growth factor beta type II receptor gene are found in a subpopulation of human pancreatic adenocarcinomas.
In this study, we determined the incidence of microsatellite instability (MIN) in pancreatic adenocarcinoma and determined whether MIN might target, for mutations, the simple nucleotide repeats of the transforming growth factor beta type II receptor (TGFBR2) gene. Forty-eight surgically resected pancreatic tumor tissue samples and two normal pancreas tissue samples were analyzed in this study. Microsatellite analysis was performed for six loci in 14 of the 48 tumor specimens for which we had matching normal genomic DNA. Only four of the 14 tumors (29%) were MIN-positive as determined by the presence of microsatellite variations in more than one locus. Interestingly, eight of the 14 specimens (57%) showed microsatellite variations or loss of heterozygosity at D18S34, suggesting that this locus may be a critical region of genetic instability in pancreatic tumorigenesis. Of the 48 tumors, only two (4%) showed mutations in the polyA region, one of the MIN-targeted sites of the TGFBR2 gene. DNA sequence analysis of these two specimens showed the presence of a two-base deletion in one tumor specimen and the other tumor specimen showed a base substitution in the polyA tract at codon 128 of the TGFBR2 gene. The fact that these mutations occurred in the polyA tract of some pancreatic tumors suggests that a subpopulation of these tumors may be susceptible to MIN-targeted mutations. The incidence of these mutations are low and similar to that reported for nonhereditary, sporadic colon cancers.
Venkatasubbarao
K
K
Department of Radiation Medicine, University of Kentucky, Lexington 40536-0084, USA.
Ahmed
M M
MM
Swiderski
C
C
Harp
C
C
Lee
E Y
EY
McGrath
P
P
Mohiuddin
M
M
Strodel
W
W
Freeman
J W
JW
D000230:Adenocarcinoma / Q000453:epidemiology / Q000235:genetics*; D003110:Colonic Neoplasms; D006801:Humans; D015994:Incidence; D018895:Microsatellite Repeats / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000453:epidemiology / Q000235:genetics*; D011061:Poly A / Q000235:genetics*; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics*; D017422:Sequence Analysis, DNA; D014407:Tumor Cells, Cultured
D018125:Receptors, Transforming Growth Factor beta; D011061:Poly A; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II