K-ras mutations in duodenal aspirate without secretin stimulation for screening of pancreatic and biliary tract carcinoma.
BACKGROUND
K-ras mutations at codon 12 (KRM) have been detected in over 80% of tissues and pure pancreatic juice (PPJ) samples from patients with pancreatic carcinoma (PCa) and are promising genetic tumor markers. Aspirating PPJ not only requires technical skill, but is also exhausting for patients. The authors attempted to evaluate whether the detection of KRM in the duodenal aspirate (DA) obtained immediately after endoscopic retrograde cholangiopancreatography (ERCP), an easier sample-collecting method than collecting PPJ, could be useful for the diagnosis of PCa and biliary tract carcinoma (BTCa).


METHODS
DA was collected endoscopically without secretin stimulation immediately after the ERCP procedure from 160 patients: 38 patients with PCa, 38 with chronic pancreatitis (CP), 22 with BTCa, 20 with adenomyomatosis of the gallbladder (AGB), 22 with cholecystolithiasis (CCL), and 20 control subjects. Mutant allele specific amplification (MASA), which is a highly sensitive method for detecting KRM, was performed, with the DNAs extracted from these samples by phenol-chloroform.


RESULTS
The incidence of KRM in DA by MASA was 25 (66%) of the 38 PCa cases, 12 (32%) of the 38 CP cases, and 12 (55%) of the 22 BTCa cases. There was no patient with positive KRM in DA among the 20 cases of AGB, 22 of CCL, and 20 control subjects. The sensitivity was 62% and the specificity 88% in this study design. The KRM incidence was found to be relatively high for the patients with PCa and BTCa by MASA, which is a highly sensitive method, although the incidence of KRM in DA from the patients with PCa was not as high as the incidence in their PPJ with secretin stimulation.


CONCLUSIONS
MASA showed a relatively high incidence of KRM even in the DA, which was easily obtained from the patients with PCa and BTCa without secretin stimulation immediately after ERCP. These results suggest that the detection of KRM in the DA by MASA is useful for the screening of both PCa and BTCa.
Watanabe
H
H
Department of Internal Medicine and Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.
Ha
A
A
Hu
Y X
YX
Ohtsubo
K
K
Yamaguchi
Y
Y
Motoo
Y
Y
Okai
T
T
Toya
D
D
Tanaka
N
N
Sawabu
N
N
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D001661:Biliary Tract Neoplasms / Q000175:diagnosis* / Q000235:genetics; D001707:Biopsy, Needle; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D004386:Duodenum / Q000473:pathology*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D005820:Genetic Testing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D012633:Secretin; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D004273:DNA, Neoplasm; D012633:Secretin