Comparison of mutations of ras oncogene in human pancreatic exocrine and endocrine tumors.
BACKGROUND
Ras oncogene mutations have been found in many human cancers; however, pancreatic endocrine tumors have rarely been studied. The purpose of this study was to analyze ras mutations in pancreatic endocrine tumors and to compare these results with the incidence of ras mutations in pancreatic exocrine cancers studied in our laboratory.


METHODS
Ras oncogene mutations were studied in 33 foregut endocrine tumors (pancreatic 31, duodenal submucosa 2). Eleven were insulinomas, 12 gastrinomas, 2 glucagonomas, and 11 others were nonfunctioning islet cell carcinomas. Thirteen were benign and 20 were malignant. These were compared with 65 pancreatic exocrine cancers. Tumors were microdissected from paraffin-embedded sections. DNA was extracted and amplified by polymerase chain reaction. Mutations were detected by a oligonucleotide hybridization method with sequence-specific phosphorus 32-radiolabeled probes.


RESULTS
No ras mutations were identified among the 33 pancreatic endocrine tumors. In contrast, 51 of 65 (78.5%) pancreatic exocrine cancers exhibited a ras mutation. Fifty were K-ras mutations and one unusual tumor exhibited a N-61 ras mutation.


CONCLUSIONS
Ras oncogene mutations do not play a role in the tumorigenesis of pancreatic endocrine tumors.
Yashiro
T
T
Department of Surgery, Howard Hughes Medical Institute, University of Chicago Pritzker School of Medicine, IL 60637.
Fulton
N
N
Hara
H
H
Yasuda
K
K
Montag
A
A
Yashiro
N
N
Straus
F
F
Ito
K
K
Aiyoshi
Y
Y
Kaplan
E L
EL
D007516:Adenoma, Islet Cell / Q000235:genetics*; D001345:Autoradiography; D001483:Base Sequence; D011905:Genes, ras; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D009693:Nucleic Acid Hybridization; D015345:Oligonucleotide Probes / Q000235:genetics; D010190:Pancreatic Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction
D015345:Oligonucleotide Probes