Infrequent microsatellite instability in biliary tract cancer.
OBJECTIVE
Microsatellite instability (MSI) has been reported in several tumors. However, few reports are available concerning MSI in biliary tract cancers. We investigated MSI and allelic loss at the hMLH1 and hMSH2 gene loci in biliary tract cancers.


METHODS
We analyzed microsatellite alterations using 7 microsatellite markers in 38 cases of extrahepatic bile duct (EHBD) cancer and 16 cases of ampullary cancer using polymerase chain reaction and an automated fluorescent DNA sequencer.


RESULTS
A MSI prevalence of 13.2% (5/38) was observed for EHBD cancer and a prevalence of 12.5% (2/16) was observed for ampullary cancer. Loss of heterozygosity at the hMLH1 and hMSH2 gene loci were observed in 4% (1/25 informative cases) and 6.1% (2/33) of EHBD cancer cases, respectively; and in 11.1% (1/9) and 8.3% (1/12) of ampullary cancer cases, respectively. The cumulative survival rate of patients with MSI was significantly better than that of patients without MSI in EHBD cancer. However, MSI was not an independent prognostic factor.


CONCLUSIONS
Our results suggest that genetic defects in the DNA mismatch repair system and MSI do not play an important role in the majority of biliary tract cancers.
Department of Surgery I, School of Medicine, Iwate Medical University, Morioka, Iwate, Japan.
T
T
Suto
W
W
Habano
T
T
Sugai
N
N
Uesugi
S
S
Kanno
K
K
Saito
S
S
Nakamura
D048868:Adaptor Proteins, Signal Transducing; D000368:Aged; D001661:Biliary Tract Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality; D002352:Carrier Proteins; D004273:DNA, Neoplasm / Q000032:analysis; D004268:DNA-Binding Proteins; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats / Q000235:genetics*; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016019:Survival Analysis
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; C497172:MSH2 protein, human; D000070957:MutL Protein Homolog 1; D051718:MutS Homolog 2 Protein