Original articles
Recurrent chromosome changes in 62 primary gastric carcinomas detected by comparative genomic hybridization

https://doi.org/10.1016/S0165-4608(00)00306-XGet rights and content

Abstract

Comparative genomic hybridization (CGH) has been applied to detect recurrent chromosome alterations in 62 primary gastric carcinomas. Several nonrandom chromosomal changes, including gains of 8q (31 cases, 50%), 20q (29 cases, 47%) with a minimum gain region at 20q11.2–q12, 13q (21 cases, 34%) with a minimum gain region at 13q22, and 3q (19 cases, 31%) were commonly observed. The regions most frequently lost included: 19p (23 cases, 37%), 17p (21 cases, 33%), and 1p (14 cases, 23%). High copy number gain (DNA sequence amplification) was detected in 6 cases. Amplification of 8q23–q24.2 and 20q11.2–q12 were observed in 3 cases. Gain of 20q and loss of 19p were confirmed by fluorescence in situ hybridization using corresponding bacterial artificial chromosomes (BAC) clones from those regions. The gain and loss of chromosomal regions identified in this study provide candidate regions involved in gastric tumorigenesis.

Introduction

Gastric cancer is considered to be the second most common cancer worldwide [1], affecting approximately 24,000 persons in the United States in 1994 [2]. The prognosis for gastric adenocarcinoma is very poor, with 5-year survival rates ranging from 5% to 20% [3]. The development of new diagnostic, preventive, and treatment approaches requires a good understanding of the mechanisms of the complex multistep process of tumorigenesis in the gastric cancer. Although several studies have been performed to study the relationship between gastric cancer and known oncogenes and tumor suppressors (e.g., amplification of ERBB-2 [4], K-SAM [5], and C-MET [6], mutations of the TP53 [7], and APC [8] genes], very little information is available detailing recurring chromosome alterations in gastric cancer because of the difficulties in karyotype analysis with conventional chromosome banding techniques.

Comparative genomic hybridization (CGH) is an approach to analyze the entire genome for regional variations of DNA sequence copy number (gain, loss, and amplification of DNA sequences) in a single experiment [9]. In CGH, equal amounts of total genomic DNA from a tumor sample and a normal control tissue are labeled with green or red fluorochromes and simultaneously hybridized to normal metaphase chromosomes. After hybridization, the fluorescence ratio between tumor and normal DNA along each reference chromosome is measured and analyzed. This technique can detect recurrent copy number changes and may highlight chromosomal regions containing genes that contribute to cancer development and/or progression. Since it was developed, CGH has been applied to study genetic alteration in many solid tumors including gastric cancer 10, 11, 12. This report using CGH examines 69 primary gastric carcinomas with several recurring chromosomal alterations that include the gain of 3q, 8q, 13q, 20q, and the loss of 1p, 17p, and 19p. Gain of 20q and loss of 19p were confirmed by interphase fluorescence in situ hybridization (FISH) using corresponding bacterial artificial chromosomes (BAC) clones.

Section snippets

Primary tumor specimens and DNA extraction

All 69 cases in this study were untreated patients from whom primary tumor tissue was collected at the time of surgical resection at the Department of Surgery, Harbin Medical University (Harbin, China), Cancer Hospital, Sun Yat-Sen University of Medical Science (Guangzhou, China), and the Department of Surgery, Norman Bethune Medical University (Changchun, China). The clinical and histopathologic data are summarized in Table 1. Tumor tissue was selected by histopathologic examination on the

Comparative genomic hybridization analysis

Comparative genomic hybridization analysis was carried out on 69 cases of primary gastric cancers. Of 69 cases, 62 showed chromosome imbalances. Three histopathologic subtypes of gastric cancer were analyzed in this study, including adenocarcinoma (44 cases), signet-ring carcinoma (9 cases), and mucin-producing adenocarcinoma (9 cases). All changes in DNA sequence copy number for the entire genome detected in these 62 primary gastric cancers are listed in Table 1 and summarized in Fig. 1. Fig. 2

Discussion

In the present study, 62 primary gastric cancers were analyzed by comparative genomic hybridization. The findings in this study are in general agreement with previous LOH and CGH results. For example, gain of 8q, 20q, and loss of 1p, 17p, and 19p have been detected as frequent chromosomal alterations in gastric cancer in at least one of the previous CGH studies 10, 11, 12.

Over-representation of 8q and 20q was the most prominent feature in this study. Gain of 8q was detected in 31/62 cases

Acknowledgements

This study is supported in part by the Leung Kwok Tze Foundation and by a Chinese National Outstading Young Scientist Award (No. 39825511).

References (24)

  • D.M Parkin et al.

    Estimates of the worldwide frequency of sixteen major cancers in 1980

    Int J Cancer

    (1988)
  • C.C Boring et al.

    Cancer statistics 1994

    CA Cancer J Clin

    (1994)
  • N Peddanna et al.

    Genetics of gastric cancer

    Anticancer Res

    (1995)
  • J Yokota et al.

    Genetic alterations of the c-erbB-2 oncogene occur frequently in tubular adenocarcinoma of the stomach and are often accompanied by amplification of the v-erbA homologue

    Oncogene

    (1988)
  • A Horii et al.

    The APC gene, responsible for familial adenomatous polyposis, is mutated in human gastric cancer

    Cancer Res

    (1992)
  • H Kuniyasu et al.

    Aberrant expression of c-met mRNA in human gastric carcinomas

    Int J Cancer

    (1993)
  • G Tamura et al.

    Detection of frequent p53 gene mutations in primary gastric cancer by cell sorting and polymerase chain reaction single-strand conformation polymorphism analysis

    Cancer Res

    (1991)
  • Y Hattori et al.

    K-sam, an amplified gene in stomach cancer, is a member of the heparin-binding growth factor receptor genes

    Proc Natl Acad Sci USA

    (1990)
  • A Kallioniemi et al.

    Comparative genomic hybridization for molecular cytogenetic analysis of solid tumors

    Science

    (1992)
  • A Kokkola et al.

    17q12–21 amplicon, a novel recurrent genetic change in intestinal type of gastric carcinomaa comparative genomic hybridization study

    Genes Chromosom Cancer

    (1997)
  • M Nessling et al.

    Mapping of chromosomal imbalances in gastric adenocarcinoma revealed amplified protooncogenes MYCN, MET, WNT2, and ERBB2

    Genes Chromosom Cancer

    (1998)
  • C Sakakura et al.

    Gains, losses, and amplifications of genomic materials in primary gastric cancers analyzed by comparative genomic hybridization

    Genes Chromosom Cancer

    (1999)
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    These authors contributed equally to this work.

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