DNA copy number profiles of gastric cancer precursor lesions
© Buffart et al; licensee BioMed Central Ltd. 2007
Received: 25 April 2007
Accepted: 01 October 2007
Published: 01 October 2007
Chromosomal instability (CIN) is the most prevalent type of genomic instability in gastric tumours, but its role in malignant transformation of the gastric mucosa is still obscure. In the present study, we set out to study whether two morphologically distinct categories of gastric cancer precursor lesions, i.e. intestinal-type and pyloric gland adenomas, would carry different patterns of DNA copy number changes, possibly reflecting distinct genetic pathways of gastric carcinogenesis in these two adenoma types.
Using a 5K BAC array CGH platform, we showed that the most common aberrations shared by the 11 intestinal-type and 10 pyloric gland adenomas were gains of chromosomes 9 (29%), 11q (29%) and 20 (33%), and losses of chromosomes 13q (48%), 6(48%), 5(43%) and 10 (33%). The most frequent aberrations in intestinal-type gastric adenoma were gains on 11q, 9q and 8, and losses on chromosomes 5q, 6, 10 and 13, whereas in pyloric gland gastric adenomas these were gains on chromosome 20 and losses on 5q and 6. However, no significant differences were observed between the two adenoma types.
The results suggest that gains on chromosomes 8, 9q, 11q and 20, and losses on chromosomes 5q, 6, 10 and 13, likely represent early events in gastric carcinogenesis. The phenotypical entities, intestinal-type and pyloric gland adenomas, however, do not differ significantly (P = 0.8) at the level of DNA copy number changes.
Gastric cancer is the second most frequent malignancy worldwide and the prognosis of this malignancy remains very poor . Gastric cancer incidence and mortality rates differ between different countries within the European Union . In the Netherlands it ranks fifth as a cause of cancer death, with approximately 2,200 new cases each year . Surgery with curative intent is the treatment of choice in advanced cases of gastric cancer, whereas local endoscopic mucosectomy can be curative in early gastric cancer. Detection and removal of gastric neoplasias in an early or even premalignant state will contribute to reduce death due to gastric cancer. To achieve this goal, better tests for early detection of gastric cancer are needed, and an improved understanding of the biology of gastric cancer progression is crucial in this respect.
According to the Correa model, pathogenesis of intestinal-type gastric adenocarcinoma follows a pathway of chronic active gastritis due to Helicobacter pylori infection, leading to mucosal atrophy, intestinal metaplasia followed by intraepithelial neoplasia and finally invasive adenocarcinoma . Genetic characterization of tissue samples in intraepithelial neoplasia stage would substantially contribute to our understanding of the molecular pathogenesis of gastric cancer. However, these lesions are only rarely detected, possibly due to rapid progression through this stage towards cancer, and are usually present only in parts of biopsy specimens, hampering genomic analysis of these lesions. Analysis of alternative precursor lesions could therefore, at least partly, be a substitute. Development of gastric cancer through an adenoma stage, although less common, is such alternative route. These adenomas are occasionally detected during gastroscopy and present as large lesions that histologically show intra-epithelial neoplasia, which makes them suitable for genomic analysis. Gastric adenomas have a direct malignant potential and account for approximately 20% of all epithelial polyps [5, 6]. Gastric adenomas can have a classic tubular, tubulovillous, or villous morphology with a predominantly intestinal-type epithelium, but can also appear as pyloric gland adenomas . Pyloric gland adenomas arise from deep mucoid glands in the stomach and are strongly positive for mucin 6 [7, 8]. A substantial number of gastric adenomas already show progression to adenocarcinoma. On first diagnosis around 30–40% of all pyloric gland adenomas already show a focus of carcinoma [9, 10]. For intestinal-type adenomas this number is lower and varies from 28,5% for villous adenomas and 29.4% for tubulovillous type adenomas to only 5.4% in the tubular adenomas . Both adenocarcinomas, ex intestinal-type adenomas and ex pyloric gland adenomas, show glandular structures, in contrast to diffuse type gastric cancer.
A key feature in the pathogenesis of most gastric cancers, as in many other solid cancers, is chromosomal instability, resulting in gains and losses of parts or even whole chromosomes . These chromosomal changes can be analyzed by comparative genomic hybridization (CGH). Several previous studies have detected genetic alterations in gastric adenomas using this technique, being gains on chromosome 7q, 8q, 13q, 20q, and losses on chromosome 4p, 5q, 9p 17p and 18q [13–16]. Although uncommon and only observed in adenomas with high grade intraepithelial neoplasia, high level amplifications have been detected on chromosomes 7q, 8p, 13q, 17q and 20q [13–16]. In gastric adenocarcinomas, consistently described chromosomal aberrations are gains on chromosome 3q, 7p, 7q, 8q, 13q, 17q and 20q and losses on chromosome 4q, 5q, 6q, 9p, 17p and 18q. High level amplifications have been repeatedly detected on 7q, 8p, 8q, 17q, 19q and 20q [14, 17–23]. Yet, chromosomal aberrations, or DNA copy number changes, are not uniform in gastric cancer . Subgroups with different patterns of DNA copy number alterations can be recognized, which have been shown to be associated with clinical outcome as well .
In the present study, we set out to study whether two morphologically distinct categories of gastric cancer precursor lesions, i.e. intestinal-type and pyloric gland adenomas, would carry different patterns of DNA copy number changes, possibly reflecting distinct genetic pathways of gastric carcinogenesis in the two adenoma types.
DNA copy number changes were observed in 10 out of 11 intestinal-type adenomas and 9 out of 10 pyloric gland adenomas. The mean number of chromosomal events, defined as gains and losses, per tumour was 6.0 (range 0–18), including 2.9 (range 0–14) gains and 3.0 (range 0–7) losses. In intestinal-type adenomas, the mean number of chromosomal events per tumour was 6.5 (range 0–18) of which 3.4 (range 0–14) gains and 3.1 (range 0–7) losses, and in the pyloric gland adenomas the mean numbers were 5.4 (range 0–9), 2.4 (range 0–7) and 3.0 (range 0–7) respectively.
In the intestinal-type gastric adenomas, the most common aberrations observed were gains on chromosomes 8, 9q and 11q, and losses on chromosomes 5q, 6, 10 and 13. In four adenomas (36.4%), gain of chromosome 11q23.3 was observed with a common region of overlap of 2.6 Mb. Gain of chromosome 9q was observed in four adenomas (36.4%) with a 12.6 Mb common region of overlap located on chromosome 9q33.1-q34.13. Gain of chromosome 8 was observed in three adenomas (31%), two of which adenomas showed gain of whole chromosome 8, and the third adenoma showed a gain of chromosome 8p-q22.3 with an additional 28.7 Mb gain on chromosome 8q24.11-qter. In addition, gains were observed on chromosomes 1, 3, 6p, 7, 11p, 12p, 13q, 16, 17, 19, 20 and 22q. No amplifications were seen in the intestinal-type adenomas.
Overview of the DNA copy number changes in 11 intestinal-type adenomas
Segment size (Mb)
The most frequent aberration observed in pyloric gland adenomas were gains on chromosome 20 and losses on chromosomes 5q and 6. Gains on chromosome 20 were seen in four adenomas (40%). Three adenomas showed a 9.8 Mb gain of chromosome 20q13.12-q13.33, and gain of whole chromosome 20 was observed in the other adenoma. In addition, gains were seen on chromosomes 1, 3q, 5q, 7, 9q, 11q, 12q, 13q, 15q, 17 and 22q. One pyloric gland adenoma showed amplifications, located on 12q13.2-q21.1 and 20q13.3-q13.33.
Overview of the DNA copy number changes in 10 pyloric gland adenomas
Segment size (Mb)
Given the heterogeneous phenotype of gastric cancer, the present study primarily aimed to compare copy number changes between intestinal-type adenomas and pyloric gland adenomas, in order to find leads towards genetic pathways involved in the pathogenesis of gastric cancer. Adenoma-to-carcinoma progression is observed in 30–40% of the pyloric gland adenomas and in approximately 5–30% of the intestinal-type adenomas (varying from about 5% in tubular adenomas to almost 30% for tubulovillous and villous adenomas) [9–11], indicating the direct malignant potential of these two adenoma types and making gastric adenomas a suitable model for detecting early events in gastric carcinogenesis.
Pyloric gland adenomas constitute a recently recognized entity [8, 26]. To the best of our knowledge, this type of adenomas has never been analyzed by array CGH before. The mean number of events in this type of adenoma was 5.4 (0–9), with 2.4 (0–7) gains and 3 (0–7) losses. This is comparable with the mean number of aberrations in intestinal-type adenomas (6.5 (0–18), 3.4 (0–14) and 3.1 (0–7) respectively). In pyloric gland adenomas, frequent events were gain on chromosome 20 and losses on chromosomes 5q and 6, while intestinal-type adenomas mainly showed gain on chromosomes 8, 9q, and 11q, and losses on chromosomes 5q, 6, 10 and 13. In the present study, gain of chromosome 7 was less common than found previously . Although these frequently altered regions differ between the two types of adenomas, hierarchical cluster analyses did not separate the groups. In addition, CGH Multiarray Region did not reveal any significant differences after correction for multiple comparisons. This lack of statistically significant differences could be due to the limited sample size combined with the fact that in general, adenomas show little chromosomal aberrations. On the other hand, it could simply be that these morphologically different entities do not differ in terms of chromosomal gains and losses. Finding no significant differences at the chromosomal level does not preclude other genetic and biological differences such as mutation or promoter methylation status of specific genes.
Aberrations already detected in adenomas may be early events in the stepwise process of accumulating changes which may cause progression of adenoma to carcinoma. As expected, the mean number of chromosomal events was lower in adenomas compared to the carcinomas [13, 14, 27]. Moreover, high level amplifications are uncommon in adenomas, while carcinomas frequently show high level amplifications [13, 16].
The aberrations found in both intestinal-type and pyloric gland adenomas, such as losses on chromosome 5q, are also frequently detected in gastric carcinomas [15, 19, 28]. Previous CGH results showed a significantly higher number of chromosome 5q losses in intestinal-type carcinoma compared to diffuse type carcinoma . Chromosome 6, also lost in both types of adenomas, frequently is deleted in gastric carcinomas as determined by LOH studies [30, 31]. Moreover, chromosome 6q deletion has been reported to be involved in an early stage of gastric carcinogenesis, since chromosome 6q deletions are frequently detected in early gastric cancer and also in intestinal metaplasia [31, 32]. Losses of chromosomes 10 and 13 have been previously observed in adenomas at lower frequencies. In gastric carcinomas, both gains and losses of chromosome 10 and 13 have been observed by previous CGH studies [15, 19, 21, 33]. Chromosome 10 harbors the oncogene FGFR2 (10q26) and tumour suppressor genes PTEN/MMAC1 (10q23) and DMBT1 (10q25-q26), both involved in carcinogenesis, which could explain the observation of both gains and losses of chromosomes 10 in gastric carcinomas [34–36]. Indeed chromosome 13 harbors tumour suppressor genes such as BRCA2 (13q12.3) and retinoblastoma gene (RB1) (13q14). In contrast, gain of chromosome 13q has been correlated to colorectal adenoma-to-carcinoma progression, and amplification of chromosome 13 has been observed in gastric adenomas with severe intraepithelial neoplasia [14, 37]. The precise role of chromosome 13 aberration in gastric cancer therefore remains to be resolved.
Most frequent copy number gains were observed on chromosomes 8, 9q, 11q and 20. Especially gains of chromosomes 8 and 20 are consistent with previous (array) CGH studies in both gastric adenomas and gastric carcinomas [13–16, 19, 25], implicating this as early events in tumourigenesis. Although gain of chromosome 11q has not been described as a frequent event in adenomas, in carcinomas gain or amplification on chromosome 11q is common [13–16]. In the present study gain of chromosome 11q was frequently observed in the adenomas, implying the malignant potential of these adenomas.
These data indicate that gains on chromosomes 8, 9q, 11q and 20 and losses on chromosomes 5q, 6, 10 and 13 are early events in gastric carcinogenesis. Despite the phenotypical differences, intestinal-type and pyloric gland adenoma do not differ significantly at the level of DNA copy number changes.
Tumour and patient information
Grade of dysplasia
Grade of dysplasie
Genomic DNA obtained from peripheral blood from ten normal individuals was pooled (either ten females or ten males, depending on the gender of the patient from which the adenoma was obtained) and used as control reference DNA.
Array CGH was performed essentially as described previously . Briefly, 300 ng tumour and reference DNAs, sex-mismatch as experimental control, were labelled by random priming (Bioprime DNA Labelling System, Invitrogen, Breda, NL), each in a volume of 50μL. Non incorporated nucleotides were removed using ProbeQuant G-50 microcolumns (Amersham Biosciences). Cy3 labelled test genomic DNA and Cy5 labelled reference DNA were combined and co-precipitated with 100μg of human Cot-1 DNA (Invitrogen, Breda, NL) by adding 0.1 volume of 3 M sodium acetate (pH 5.2) and 2.5 volumes of ice-cold 100% ethanol. The precipitate was collected by centrifugation at 14,000 rpm for 30 minutes at 4°C, and dissolved in 130 μl hybridization mixture containing 50% formamide, 2 × SCC and 4% SDS. The hybridization solution was heated for 10 minutes at 73°C to denature the DNA, followed by 60–120 minutes incubation at 37°C to allow the Cot-1 DNA to block repetitive sequences. The mixture was hybridized on an array containing approximately 5000 clones spotted in triplicate and spread along the whole genome with an average resolution of 1.0 Mb. The clones are comprised of the Sanger BAC clone set with an average resolution along the whole genome of 1.0 Mb , the OncoBac set , and selected clones of interest, obtained from the Children's Hospital Oakland Research Institute (CHORI). The selected clones comprise a collection of BAC clones on chromosome 6 filling the gaps larger than 1 Mb, and full-coverage contigs on specific regions on chromosomes 8, 13 and 20. Hybridization was performed in a in a hybridization station (Hybstation12 – Perkin Elmer Life Sciences, Zaventem, BE) and incubated for 38 h at 37°C. After hybridization, slides were washed in a solution containing 50% formamide, 2× SCC, pH 7 for 3 minutes at 45°C, followed by 1 minute wash steps at room temperature with PN buffer (PN: 0.1 M sodiumphosphate, 0.1% nonidet P40, pH 8), 0.2× SSC, 0.1× SCC and 0.01× SCC.
Image acquisition and data analysis
Images of the arrays were acquired by scanning (Agilent DNA Microarray scanner- Agilent technologies, Palo Alto, USA) and quantification of the signal and background intensities for each spot for the two channels Cy3 and Cy5 was performed by Imagene 5.6 software (Biodiscovery Ltd, Marina del Rey, CA, USA). Local background was subtracted from the signal median intensities and tumours to reference ratios were calculated. The ratios were normalized against the mode of the ratios of all autosomes. Clones with poor quality of one of the triplicates and hybridization with a standard deviation (SD) ≤ 0.22 and clones with > 50% missing values in all adenomas were excluded, leaving 4648 clones for further analysis. All subsequent analyses were done considering the clone position from the UCSC May2004 freeze of the Human Golden Path.
Array CGH smooth [42, 43], was used for automated detection of breakpoints to determine copy number gains and losses. Since variation in quality is observed in DNA obtained from formalin-fixed paraffin-embedded gastric tissues, different smoothing parameters were applied, depending on the quality of the hybridization. For array CGH profiles with a standard deviation smaller or equal to 0.15, between 0.15 and 0.20 or between 0.20 and 0.22, the applied smoothing parameters to determine gains and losses were 0.10, 0.15 and 0.20 respectively. Log2 tumour to reference ratio above 1 was regarded as amplification.
Unsupervised hierarchical cluster analysis was performed to analyze the distributions of the genomic profiles of all adenomas using TMEV software 3.0.3 . Based on normalized smoothed log2 tumour to normal fluorescence intensity ratios, a hierarchical tree was constructed using the parameters complete linkage and euclidean distance. Pearson Chi-square test was used for analyzing correlations between cluster membership and adenoma type (SPSS 11.5.0 for windows, SPSS Inc, Chicago, IL, USA). P-values less than 0.05 were considered to be significant.
Supervised analysis was used for identifying chromosomal regions specific for the two adenoma types using CGH Multiarray and CGH Multiarray Region [45, 46]. Based on normalized smoothed log2 tumour to normal fluorescence intensity ratios, p-values were calculated for the significance of difference of values for each clone between pyloric gland and intestinal-type adenomas, using a Wilcoxon test with ties. To correct for multiple testing, a permutation-based false discovery rate (FDR) was calculated .
We thank the Mapping Core and Map Finishing groups of the Wellcome Trust Sanger Institute for initial clone supply and verification. This work was financially supported by the Portuguese Foundation for Science and Technology (FCT), grant POCTI/CBO/41179/2001 and by Dutch Cancer Society grant-KWF 2004–3051.
- Parkin DM, Pisani P, Ferlay J: Global cancer statistics. CA Cancer J Clin. 1999, 49: 33-64, 1.PubMedView ArticleGoogle Scholar
- Black RJ, Bray F, Ferlay J, Parkin DM: Cancer incidence and mortality in the European Union: cancer registry data and estimates of national incidence for 1990. Eur J Cancer. 1997, 33: 1075-1107. 10.1016/S0959-8049(96)00492-3.PubMedView ArticleGoogle Scholar
- Visser O, Coebergh J, Schouten L, Dijck J: Incidence of Cancer in The Netherlands 1997. Utrecht. 2001Google Scholar
- Correa P, Haenszel W, Cuello C, Tannenbaum S, Archer M: A model for gastric cancer epidemiology. Lancet. 1975, 2: 58-60. 10.1016/S0140-6736(75)90498-5.PubMedView ArticleGoogle Scholar
- Oberhuber G, Stolte M: Gastric polyps: an update of their pathology and biological significance. Virchows Arch. 2000, 437: 581-590. 10.1007/s004280000330.PubMedView ArticleGoogle Scholar
- Stolte M, Sticht T, Eidt S, Ebert D, Finkenzeller G: Frequency, location, and age and sex distribution of various types of gastric polyp. Endoscopy. 1994, 26: 659-665.PubMedView ArticleGoogle Scholar
- Borchard F, Ghanei A, Koldovski U, Hengels KJ, Buckmann FW: Gastrale Differenzierung in Adenomen der Magenschleim. Immunohistochemische und elektronmikroskopische Untersuchen. Verh Dtsch Ges Pathol. 1990, 74: 528-524.Google Scholar
- Hamilton SR, Aaltonen LS: WHO Classification. Tumors of the gastrointestinal tract. Pathology and genetics. IARC Press, Lyon. 2000, --20.Google Scholar
- Stolte M: Clinical consequences of the endoscopic diagnosis of gastric polyps. Endoscopy. 1995, 27: 32-37.PubMedView ArticleGoogle Scholar
- Vieth M, Kushima R, Borchard F, Stolte M: Pyloric gland adenoma: a clinico-pathological analysis of 90 cases. Virchows Arch. 2003, 442: 317-321.PubMedGoogle Scholar
- Schmitz JM, Stolte M: Gastric polyps as precancerous lesions. Gastrointest Endosc Clin N Am. 1997, 7: 29-46.PubMedGoogle Scholar
- Lengauer C, Kinzler KW, Vogelstein B: Genetic instabilities in human cancers. Nature. 1998, 396: 643-649. 10.1038/25292.PubMedView ArticleGoogle Scholar
- Kim YH, Kim NG, Lim JG, Park C, Kim H: Chromosomal alterations in paired gastric adenomas and carcinomas. Am J Pathol. 2001, 158: 655-662.PubMed CentralPubMedView ArticleGoogle Scholar
- Kokkola A, Monni O, Puolakkainen P, Nordling S, Haapiainen R, Kivilaakso E, Knuutila S: Presence of high-level DNA copy number gains in gastric carcinoma and severely dysplastic adenomas but not in moderately dysplastic adenomas. Cancer Genet Cytogenet. 1998, 107: 32-36. 10.1016/S0165-4608(98)00092-2.PubMedView ArticleGoogle Scholar
- van Dekken H, Alers JC, Riegman PH, Rosenberg C, Tilanus HW, Vissers K: Molecular cytogenetic evaluation of gastric cardia adenocarcinoma and precursor lesions. Am J Pathol. 2001, 158: 1961-1967.PubMed CentralPubMedView ArticleGoogle Scholar
- Weiss MM, Kuipers EJ, Postma C, Snijders AM, Stolte M, Vieth M, Pinkel D, Meuwissen SG, Albertson D, Meijer GA: Genome wide array comparative genomic hybridisation analysis of premalignant lesions of the stomach. Mol Pathol. 2003, 56: 293-298. 10.1136/mp.56.5.293.PubMed CentralPubMedView ArticleGoogle Scholar
- Kimura Y, Noguchi T, Kawahara K, Kashima K, Daa T, Yokoyama S: Genetic alterations in 102 primary gastric cancers by comparative genomic hybridization: gain of 20q and loss of 18q are associated with tumor progression. Mod Pathol. 2004, 17: 1328-1337. 10.1038/modpathol.3800180.PubMedView ArticleGoogle Scholar
- Koo SH, Kwon KC, Shin SY, Jeon YM, Park JW, Kim SH, Noh SM: Genetic alterations of gastric cancer: comparative genomic hybridization and fluorescence In situ hybridization studies. Cancer Genet Cytogenet. 2000, 117: 97-103. 10.1016/S0165-4608(99)00152-1.PubMedView ArticleGoogle Scholar
- Sakakura C, Mori T, Sakabe T, Ariyama Y, Shinomiya T, Date K, Hagiwara A, Yamaguchi T, Takahashi T, Nakamura Y, Abe T, Inazawa J: Gains, losses, and amplifications of genomic materials in primary gastric cancers analyzed by comparative genomic hybridization. Genes Chromosomes Cancer. 1999, 24: 299-305. 10.1002/(SICI)1098-2264(199904)24:4<299::AID-GCC2>3.0.CO;2-U.PubMedView ArticleGoogle Scholar
- Takada H, Imoto I, Tsuda H, Sonoda I, Ichikura T, Mochizuki H, Okanoue T, Inazawa J: Screening of DNA copy-number aberrations in gastric cancer cell lines by array-based comparative genomic hybridization. Cancer Sci. 2005, 96: 100-110. 10.1111/j.1349-7006.2005.00016.x.PubMedView ArticleGoogle Scholar
- van Grieken NC, Weiss MM, Meijer GA, Hermsen MA, Scholte GH, Lindeman J, Craanen ME, Bloemena E, Meuwissen SG, Baak JP, Kuipers EJ: Helicobacter pylori-related and -non-related gastric cancers do not differ with respect to chromosomal aberrations. J Pathol. 2000, 192: 301-306. 10.1002/1096-9896(2000)9999:9999<::AID-PATH697>3.0.CO;2-F.PubMedView ArticleGoogle Scholar
- Weiss MM, Kuipers EJ, Hermsen MA, van Grieken NC, Offerhaus J, Baak JP, Meuwissen SG, Meijer GA: Barrett's adenocarcinomas resemble adenocarcinomas of the gastric cardia in terms of chromosomal copy number changes, but relate to squamous cell carcinomas of the distal oesophagus with respect to the presence of high-level amplifications. J Pathol. 2003, 199: 157-165. 10.1002/path.1260.PubMedView ArticleGoogle Scholar
- Wu CW, Chen GD, Fann CS, Lee AF, Chi CW, Liu JM, Weier U, Chen JY: Clinical implications of chromosomal abnormalities in gastric adenocarcinomas. Genes Chromosomes Cancer. 2002, 35: 219-231. 10.1002/gcc.10106.PubMedView ArticleGoogle Scholar
- Buffart T, Carvalho B, Hopmans E, Brehm V, Kranenbarg EK, Schaaij-Visser T, Eijk P, van Grieken N, Ylstra B, van de Velde CJ, Meijer G: Gastric cancers in young and elderly patients show different genomic profiles. J Pathol. 2007, 211: 45-51. 10.1002/path.2085.PubMedView ArticleGoogle Scholar
- Weiss MM, Kuipers EJ, Postma C, Snijders AM, Pinkel D, Meuwissen SG, Albertson D, Meijer GA: Genomic alterations in primary gastric adenocarcinomas correlate with clinicopathological characteristics and survival. Cell Oncol. 2004, 26: 307-317.PubMedGoogle Scholar
- Kushima R, Ruthlein HJ, Stolte M, Bamba M, Hattori T, Borchard F: 'Pyloric gland-type adenoma' arising in heterotopic gastric mucosa of the duodenum, with dysplastic progression of the gastric type. Virchows Arch. 1999, 435: 452-457. 10.1007/s004280050425.PubMedView ArticleGoogle Scholar
- Weiss MM, Kuipers EJ, Postma C, Snijders AM, Siccama I, Pinkel D, Westerga J, Meuwissen SG, Albertson DG, Meijer GA: Genomic profiling of gastric cancer predicts lymph node status and survival. Oncogene. 2003, 22: 1872-1879. 10.1038/sj.onc.1206350.PubMedView ArticleGoogle Scholar
- Oga A, Kong G, Ishii Y, Izumi H, Park CY, Sasaki K: Preferential loss of 5q14-21 in intestinal-type gastric cancer with DNA aneuploidy. Cytometry. 2001, 46: 57-62. 10.1002/1097-0320(20010215)46:1<57::AID-CYTO1038>3.0.CO;2-5.PubMedView ArticleGoogle Scholar
- Wu MS, Chang MC, Huang SP, Tseng CC, Sheu JC, Lin YW, Shun CT, Lin MT, Lin JT: Correlation of histologic subtypes and replication error phenotype with comparative genomic hybridization in gastric cancer. Genes Chromosomes Cancer. 2001, 30: 80-86. 10.1002/1098-2264(2000)9999:9999<::AID-GCC1062>3.0.CO;2-R.PubMedView ArticleGoogle Scholar
- Carvalho B, Seruca R, Carneiro F, Buys CH, Kok K: Substantial reduction of the gastric carcinoma critical region at 6q16.3-q23.1. Genes Chromosomes Cancer. 1999, 26: 29-34. 10.1002/(SICI)1098-2264(199909)26:1<29::AID-GCC4>3.0.CO;2-D.PubMedView ArticleGoogle Scholar
- Queimado L, Seruca R, Costa-Pereira A, Castedo S: Identification of two distinct regions of deletion at 6q in gastric carcinoma. Genes Chromosomes Cancer. 1995, 14: 28-34. 10.1002/gcc.2870140106.PubMedView ArticleGoogle Scholar
- Li BC, Chan WY, Li CY, Chow C, Ng EK, Chung SC: Allelic loss of chromosome 6q in gastric carcinoma. Diagn Mol Pathol. 2003, 12: 193-200. 10.1097/00019606-200312000-00003.PubMedView ArticleGoogle Scholar
- Peng DF, Sugihara H, Mukaisho K, Tsubosa Y, Hattori T: Alterations of chromosomal copy number during progression of diffuse-type gastric carcinomas: metaphase- and array-based comparative genomic hybridization analyses of multiple samples from individual tumours. J Pathol. 2003, 201: 439-450. 10.1002/path.1459.PubMedView ArticleGoogle Scholar
- Katoh M, Katoh M: FGFR2 and WDR11 are neighboring oncogene and tumor suppressor gene on human chromosome 10q26. Int J Oncol. 2003, 22: 1155-1159.PubMedGoogle Scholar
- Mori M, Shiraishi T, Tanaka S, Yamagata M, Mafune K, Tanaka Y, Ueo H, Barnard GF, Sugimachi K: Lack of DMBT1 expression in oesophageal, gastric and colon cancers. Br J Cancer. 1999, 79: 211-213.PubMed CentralPubMedView ArticleGoogle Scholar
- Wang JY, Huang TJ, Chen FM, Hsieh MC, Lin SR, Hou MF, Hsieh JS: Mutation analysis of the putative tumor suppressor gene PTEN/MMAC1 in advanced gastric carcinomas. Virchows Arch. 2003, 442: 437-443.PubMedGoogle Scholar
- Hermsen M, Postma C, Baak J, Weiss M, Rapallo A, Sciutto A, Roemen G, Arends JW, Williams R, Giaretti W, De Goeij A, Meijer G: Colorectal adenoma to carcinoma progression follows multiple pathways of chromosomal instability. Gastroenterology. 2002, 123: 1109-1119. 10.1053/gast.2002.36051.PubMedView ArticleGoogle Scholar
- Weiss MM, Hermsen MA, Meijer GA, van Grieken NC, Baak JP, Kuipers EJ, van Diest PJ: Comparative genomic hybridisation. Mol Pathol. 1999, 52: 243-251.PubMed CentralPubMedView ArticleGoogle Scholar
- Snijders AM, Nowak N, Segraves R, Blackwood S, Brown N, Conroy J, Hamilton G, Hindle AK, Huey B, Kimura K, Law S, Myambo K, Palmer J, Ylstra B, Yue JP, Gray JW, Jain AN, Pinkel D, Albertson DG: Assembly of microarrays for genome-wide measurement of DNA copy number. Nat Genet. 2001, 29: 263-264. 10.1038/ng754.PubMedView ArticleGoogle Scholar
- ensembl . 2007, [http://www.ensembl.org/Homo_sapiens/cytoview]
- informa. 2007, [http://informa.bio.caltech.edu/Bac_onc.html]
- Jong K, Marchiori E, van der Vaart AV, Ylstra B, Weiss MM, Meijer G: Chromosomal breakpoint detection in human cancer. In LNCN. 2003, 2611: 54-65.Google Scholar
- Jong K, Marchiori E, Meijer G, Vaart AV, Ylstra B: Breakpoint identification and smoothing of array comparative genomic hybridization data. Bioinformatics. 2004, 20: 3636-3637. 10.1093/bioinformatics/bth355.PubMedView ArticleGoogle Scholar
- tigr . 2007, [http://www.tigr.org/software]
- CGH Multiarray. 2007, [http://www.few.vu.nl/~mavdwiel/]
- van de Wiel MA, Smeets SJ, Brakenhoff RH, Ylstra B: CGHMultiArray: exact P-values for multi-array comparative genomic hybridization data. Bioinformatics. 2005, 21: 3193-3194. 10.1093/bioinformatics/bti489.PubMedView ArticleGoogle Scholar
- Manduchi E, Grant GR, McKenzie SE, Overton GC, Surrey S, Stoeckert CJ: Generation of patterns from gene expression data by assigning confidence to differentially expressed genes. Bioinformatics. 2000, 16: 685-698. 10.1093/bioinformatics/16.8.685.PubMedView ArticleGoogle Scholar
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.