以比較基因雜交法和微衛星體分析研究與胰臟癌有關的基因變化特徵(3/3)
Other Title
Characterization of genomic alterations associated with pancreatic cancer by
comparative genomic hybridization and microsatellite analysis(3/3)
comparative genomic hybridization and microsatellite analysis(3/3)
Date Issued
2002
Date
2002
Author(s)
林肇堂
DOI
902314B002142
Abstract
About 90% of pancreatic tumors are adenocarcinomas with a ductal phenotype. They differ
from adenocarcinoma of the distal bile duct, ampulla of Vater and mucinous cystic carcinoma in
terms of clinical manifestations and prognosis. Increasing evidence indicates that pancreatic cancer
(PC) development is a multistep event proceeding from normal, preneoplastic lesions, to highly
malignant tumor accompanied by accumulations of multiple genetic alterations. Collectively, it was
believed that variability in the biologic characteristics of PC may be related to the profile of genetic
alterations. Delineating genes involved in development and progression of PC can reflect the
heterogeneity of their causes and subtypes. However, genetic changes underlying the initiation and
progression of PC lack systemic data. This is partly attributable to the limitation of current research
techniques such as manual microdissection and conventional cytogenetics. This project has been
designed to further investigate the chromosomal aberrations of PC, identify target genes for DNA
amplifications and losses in PC, clarify different genetic alterations in the development of PC, and
elucidate the relationship between genetic abnormalities and different subtypes of PC.
In the first year grant period, we have collected the following cases retrospectively and
prospectively. To obtain pure cancer cells for further DNA analysis, laser capture microdissection
(LCM) was performed in 15 cases with PC. K-ras mutations were investigated in the subsequently
extracted DNA and disclosed GGTàGAT point mutation at codon 12 in 9 cases (Table 1). These
results indicated LCM could be successfully applied to investigate PC. Different data were reported
about the k-ras mutation rate by using different methods or material in the literature (reference 13).
However, abdance of stromal cell DNA will easily contaminate the analysis of genetic alterations of
pancreatic cancers. Microdisseciton is strongly suggested in investigation of pancreatic cancers
nowadays. Our report is the first one which analyzed the “true” k-ras mutation rate in pancreatic
cancer using laser capture microdissection. Besides, the relative lower rate of k-ras mutation may
echo the newly classified category of PC, medullary caninoma of pancreas, which imply a different
caninogenesis (reference 14).
In the second year grant period, we performed immunohistochemical analysis of cell cycle
proteins, including p16, Rb, cyclin D and p53 in our specimens. The data showed 70%(21/30) of pc
with Rb changes; 40%(12/30) with mutant p53; 26.7%(8/30) with p16 changes and 26.7%(8/30)
with cyclin D changes. Besides, in the cancers of papilla of vater, 68%(17/25) was with Rb changes;
24%(6/25) with mutant p53; 4%(2/25) with p16 changes and 56%(14/25) with cyclin D changes
(Table 2). There is no obvious statistical difference between above 2 groups noticed. However,
further analysis of these genes is mandatory to elucidate the role of these genes in cancinogenesis of
pancreatic cancer.
In addition to continuously enrolling more specimens LCM-procured pure DNA of pancreatic cancer and noncancerous tissue were be further analyzed in the last year period. The comparative
genomic hybridization which we have established in gastric cancer (references 15-20) was applied
to study the genetic profiles of these samples and elucidate the clinicopathologic significance of
genetic abnormalities in the third year grant period. We found that chromosomes gains occurred
more frequently in 1p(36.4%), 2p(36.4%), 2q(36.4%), 3q(45.5%), 5p(63.6%), 7p(36.4%),
8q(45.5%), 9p(36.4%), 13q(54.5%), 18q(36.4%), 21q(36.4%), Xp(31.4%). In the other hands,
chromosome loss occurred more frequently in chromosome 1p(36.4%), 1q(27.3%), 2q(27.3%),
3p(27.3%), 7p(27.3%), 11q(36.4%), 16q(27.3%), 17p(63.6%), 17q(27.3%), 18q(45.5%), 19q(36.4%)
(Table 3).
In this project, we also noticed that some genomic DNA extracted from paraffin embedded
formalin fired tissues might be well- applicated by DOP-PCR followed by CGH. However, some
cases even though dealt with OCT might not be feasible in such applications. Therefore, some
valuable experiences in dealing with tissue observation and management also were obtained in this
grant period. We will keep on collecting suitable specimens and completing more data based on the
present results in the future.
Subjects
Pancreatic cancer
Genetic alterations
Laser capture microdiseection
Comparative
genomic hybridization
genomic hybridization
Microsatellite analysis
SDGs
Publisher
臺北市：國立臺灣大學醫學院內科
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
902314B002142.pdf
Size
127.21 KB
Format
Adobe PDF
Checksum
(MD5):4cacacc047e598e6b70ddf38c41df52c