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Jackson CL, Hang S, Hansen K, He M, Sung CJ, Quddus MR, Xiong M, Wang Y, Patel NR, Lawrence WD, Xiong J. Endometrial Adenocarcinomas With Significant Mucinous Differentiation: A Characterization of Intratumoral Heterogeneity of KRAS Mutations in Mucinous and Endometrioid Histologic Components. Int J Gynecol Cancer 2019; 28:241-247. [PMID: 29303928 DOI: 10.1097/igc.0000000000001168] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE KRAS mutations are frequently seen in malignancies with mucinous morphology. In our previous study, mucinous endometrial carcinomas were associated with a significantly higher frequency of KRAS mutations as compared with matched conventional endometrioid carcinomas. This study expands our previous report by exploring possible intratumoral heterogeneity for KRAS gene mutations in the mucinous components of mucinous carcinomas (MCs) and endometrioid carcinomas with significant mucinous differentiation (ECSMD) versus their associated "usual" endometrioid components. MATERIALS AND METHODS KRAS-positive cases from our previous report were studied, including 10 MCs and 10 ECSMDs. The specimens were microscopically dissected to separately isolate morphologically mucinous and endometrioid components. Direct DNA sequencing for KRAS mutations at codons 12 and 13 using capillary electrophoresis were performed. RESULTS KRAS mutations were detected in the endometrioid components of 8 (80%) of 10 MCs and 3 (30%) of 10 ECSMDs. The endometrioid component of the ECSMD group was less frequently associated with KRAS mutation than the endometrioid component of the MC group, even when the mucinous component of the same tumor contained a mutation; the difference is statistically significant (P < 0.05). CONCLUSIONS Our current study shows that intratumoral heterogeneity for KRAS gene mutation was associated with ECSMD, but less frequently with MC. It is possible that when the mucinous component predominates, qualifying for an MC, KRAS mutations appear to be widespread, irrespective of the mucinous or nonmucinous differentiation of the tumor cells. The findings suggest that multiple samples for KRAS tests may be useful, especially in endometrioid carcinoma with significant mucinous differentiation.
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Sebagh M, Bosselut N, Santos AD, Allard MA, Ruiz A, Saffroy R, Cherqui D, Vibert E, Castaing D, Adam R, Cunha AS, Lemoine A. Rare genetic heterogeneity within single tumor discovered for the first time in colorectal liver metastases after liver resection. Oncotarget 2018; 9:21921-21929. [PMID: 29774112 PMCID: PMC5955166 DOI: 10.18632/oncotarget.25119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 03/21/2018] [Indexed: 02/07/2023] Open
Abstract
Effective individualized treatment of patients with colorectal liver metastases (CLM) requires tumor genotyping, usually based on the analysis of one single sample per patient. Therapy failure may partially be explained by sampling errors and/or intratumoral genetic heterogeneity. We aimed to demonstrate intratumoral genetic heterogeneity in CLM and enable pathologists to select tumor tissue for genotyping. All the tumors of 86 patients who underwent liver resection for a single CLM were reviewed. Of the 86 patients, 66 patients received chemotherapy and 20 patients did not receive chemotherapy before liver resection. All the tumor areas sampled were analyzed for KRAS, BRAF, PIK3CA, and NRAS mutations. The mutational status was tested in 74 cases, 7 cases had no tumoral cells due to complete responses and 5 blocks were unavailable. Of the 59/74 CLM with > 1 sample, 56 showed the same mutational status between the samples. The remaining 3 cases (5% of all cases) showed genetic heterogeneity for KRAS in 2 and BRAF in 1 patient. Genetic heterogeneity correlated with lower rate of viable tumor cells (p=0.009) and higher rate of mucin pools (p=0.013). We demonstrate for the first time the existence of genetic intratumoral heterogeneity in 5% of CLM. In routine practice, this low incidence does not require the genotyping of additional tumor samples. The correlation between the genetic heterogeneity and some histological components of the CLM should be verified by further in situ mutation assay.
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Affiliation(s)
- Mylène Sebagh
- AP-HP Hôpital Paul Brousse, Laboratoire d'Anatomie Pathologique, Villejuif, France.,Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France
| | - Nelly Bosselut
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul Brousse, Département d'Oncogénétique, Villejuif, France
| | - Alexandre Dos Santos
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France
| | - Marc-Antoine Allard
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France.,Inserm, Unité 935, Université Paris-Saclay, Villejuif, France
| | - Aldrick Ruiz
- AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France.,University Medical Center Utrecht, Department of Surgery, Utrecht, The Netherlands
| | - Raphaël Saffroy
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul Brousse, Département d'Oncogénétique, Villejuif, France
| | - Daniel Cherqui
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France
| | - Eric Vibert
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France
| | - Denis Castaing
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France
| | - René Adam
- Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France.,Inserm, Unité 935, Université Paris-Saclay, Villejuif, France
| | - Antonio Sa Cunha
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul-Brousse, Centre Hépato-Biliaire, Villejuif, France
| | - Antoinette Lemoine
- Inserm, Unité 1193, Université Paris-Saclay, Villejuif, France.,Univ Paris-Sud, UMR-S 1193, Université Paris-Saclay, Villejuif, France.,DHU Hepatinov, Villejuif, France.,AP-HP Hôpital Paul Brousse, Département d'Oncogénétique, Villejuif, France
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Kershaw SK, Byrne HM, Gavaghan DJ, Osborne JM. Colorectal cancer through simulation and experiment. IET Syst Biol 2013; 7:57-73. [DOI: 10.1049/iet-syb.2012.0019] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Sophie K. Kershaw
- Department of Computer ScienceComputational Biology GroupWolfson Building, Parks RoadOxfordOX1 3QDUK
| | - Helen M. Byrne
- Department of Computer ScienceComputational Biology GroupWolfson Building, Parks RoadOxfordOX1 3QDUK
- OCCAM, Mathematical Institute24-29 St. Giles’OxfordOX1 3LBUK
| | - David J. Gavaghan
- Department of Computer ScienceComputational Biology GroupWolfson Building, Parks RoadOxfordOX1 3QDUK
- Department of BiochemistryOxford Centre for Integrative Systems BiologySouth Parks RoadOxfordOX1 3QUUK
| | - James M. Osborne
- Department of Computer ScienceComputational Biology GroupWolfson Building, Parks RoadOxfordOX1 3QDUK
- Department of BiochemistryOxford Centre for Integrative Systems BiologySouth Parks RoadOxfordOX1 3QUUK
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Kaneko Y, Kuramochi H, Nakajima G, Inoue Y, Yamamoto M. Degraded DNA may induce discordance of KRAS status between primary colorectal cancer and corresponding liver metastases. Int J Clin Oncol 2013; 19:113-20. [PMID: 23299277 DOI: 10.1007/s10147-012-0507-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Accepted: 12/02/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND KRAS mutation is widely accepted as a strong, negative predictive marker for anti-epidermal growth factor receptor antibodies, including cetuximab and panitumumab. Previous reports demonstrated approximately 100 % concordance of KRAS status between primary colorectal cancer and liver metastases; however, mismatched KRAS status still occurs. METHODS KRAS status was evaluated in 105 pairs of formalin-fixed primary colorectal cancer and corresponding liver metastases specimens by direct sequencing. DNA quality of patients displaying mismatched KRAS status between primary tumors and metastases was assessed using a Bioanalyzer. RESULTS KRAS status was successfully analyzed in 90/105 patients (85.7 %). The concordance rate between primary tumors and metastases was 88.2 % in synchronous metastases (n = 76) and 100 % in metachronous metastases (n = 14). Discordance in KRAS status was observed in nine patients. Independent method validation revealed only five samples showed the same KRAS status between the two methods. DNA quality assessment by a Bioanalyzer revealed that the median length of DNA samples in the peak concentration of the mismatched group was significantly shorter than those in the control group (153.5 vs 276.5 bp, P = 0.0059). In addition, the median value of the percentage of degraded DNA (0-200 bp) in each sample in the mismatched group was significantly higher than the control group (35.5 vs 22 %, P = 0.020). These data suggest that the discordant results for these nine patients (18 samples) were due to low quality DNA, which may obscure polymerase chain reaction analysis, affecting sequencing reliability. CONCLUSION Quality control and assurance of KRAS genotyping is critical, and standardization of the methodology is warranted.
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Affiliation(s)
- Yuka Kaneko
- Department of Gastroenterological Surgery, Tokyo Women's Medical University, 8-1 Kawadacho, Shinjuku-ku, Tokyo, Japan
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5
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Buob D, Fauvel H, Buisine MP, Truant S, Mariette C, Porchet N, Wacrenier A, Copin MC, Leteurtre E. The complex intratumoral heterogeneity of colon cancer highlighted by laser microdissection. Dig Dis Sci 2012; 57:1271-80. [PMID: 22198706 DOI: 10.1007/s10620-011-2023-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/05/2011] [Indexed: 01/01/2023]
Abstract
AIMS To evaluate the utility of laser microdissection in the comparison of phenotypes and genetic alterations between colon cancer and corresponding liver metastasis in the context of intratumoral heterogeneity. METHODS Immunohistochemistry was performed on a series of 11 patients surgically treated for colon adenocarcinoma with liver metastases, using antibodies directed against six mucins. Immunohistochemistry was completed by laser microdissection of tumor zones with particular phenotype, luminal zone and invasion front of colon tumors. Microdissected samples were compared on the basis of microsatellite instability and alterations of CTNNB1, KRAS, and TP53. RESULTS Our study demonstrated varying mucin expression within tumors, suggesting the existence of phenotypic intratumoral heterogeneity. A common immunohistochemical profile was observed in individual tumors between tumoral subpopulations and corresponding metastases. Nevertheless, the phenotypic characteristics were distinct from one patient to another. Laser microdissection underlined that phenotypic heterogeneity could rely on genotypic heterogeneity, and that some genetic alterations were common to microdissected samples from primary colon tumors and liver metastases. CONCLUSION We illustrated intratumoral heterogeneity of colon cancer using laser microdissection, in combination with immunohistochemical and genotypic tools. This intratumoral heterogeneity could represent a major issue in the search of prognostic biomarkers.
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Affiliation(s)
- David Buob
- Department of Pathology, CHRU de Lille, Centre de Biologie Pathologie, Avenue Oscar Lambret, 59037 Lille Cedex, France.
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6
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Heterogeneous distribution of K-ras mutations in primary colon carcinomas: implications for EGFR-directed therapy. Int J Colorectal Dis 2011; 26:1271-7. [PMID: 21573767 DOI: 10.1007/s00384-011-1233-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/03/2011] [Indexed: 02/04/2023]
Abstract
PURPOSE K-ras mutations predict resistance against epidermal growth factor receptor (EGFR)-directed therapy of metastatic colorectal cancer (CRC). The purpose of this study was to analyze the distribution of K-ras mutations in primary tumors and corresponding sentinel lymph nodes (SLNs) from colon cancer patients. METHODS Tumor biopsies and SLNs from 158 patients with non-metastatic colon cancer were analyzed for K-ras mutations in codons 12 and 13 by a sensitive and quantitative peptide nucleic acid clamp PCR assay. RESULTS Analyses of single fresh-frozen tumor biopsies revealed K-ras mutations in 67 (42%) of the patients. Apparently low levels of K-ras mutations in 13 of the mutated primary tumors and the presence of K-ras mutations in SLNs from seven patients with a wild-type primary tumor biopsy suggested possible intratumoral heterogeneity for 20 of the patients. To confirm this hypothesis, we analyzed tissue sections from all available formalin-fixed, paraffin-embedded (FFPE) tumor blocks from these 20 patients. Ten of the patients had a mixture of tissue sections positive and tissue sections negative for K-ras mutations, two patients had K-ras mutations in all sections, and eight patients had no detectable K-ras mutations in tumor FFPE tissue blocks. Among these eight patients, five had K-ras mutations detected in SLNs. Thus, evidence supporting a heterogeneous distribution of K-ras mutations was obtained for 15 patients. CONCLUSIONS Heterogeneous distribution of K-ras codon 12 and 13 mutations within primary tumor, or between primary tumor and lymph node metastases, was demonstrated for 15 (20%) of 74 colon cancer patients having K-ras mutations. This may have implications for tissue sampling routines with regard to EGFR-directed therapy of CRC, both in adjuvant and metastatic settings.
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7
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Heterogeneity of KRAS status may explain the subset of discordant KRAS status between primary and metastatic colorectal cancer. Dis Colon Rectum 2011; 54:1170-8. [PMID: 21825899 DOI: 10.1097/dcr.0b013e31821d37a3] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND KRAS status is a useful predictive marker for anti-epidermal growth factor receptor antibody therapy. OBJECTIVE This study aimed to examine the concordance rate of KRAS mutation status between corresponding primary and metastatic colorectal cancer lesions, and also among multiple metastatic tumors. Furthermore, we examined the heterogeneity of KRAS mutations with respect to discordant KRAS status between primary and metastatic tumors. DESIGN AND SETTINGS This study was retrospective in design. PATIENTS Forty-three patients with primary tumors and 113 metastatic tumors were studied. MAIN OUTCOME MEASURES The KRAS mutational status was determined by the peptide nucleic acid clamp real-time polymerase chain reaction TaqMan assay. We also performed sequencing analysis to validate the KRAS mutational status. When KRAS status differed between primary and metastatic tumors, we examined the heterogeneity of KRAS status within individual primary tumors by microdissecting multiple samples in each patient. RESULTS The frequency of KRAS mutations in primary tumors was 34.9%. A high concordance rate of KRAS (88.4-91.7%) mutations was observed between primary and metastatic tumors. All 5 cases (11.6%) with discordant KRAS status had heterogeneous KRAS status in primary tumors. However, in 10 concordant cases all microdissected areas showed an identical KRAS mutational status within each patient. The KRAS mutational statuses in all multiple liver and/or lung metastatic tumors were the same as those of the primary tumor. LIMITATIONS We could not validate KRAS status in microdissected samples by the direct sequence method that was used in the present study, because the quantity of DNA was not sufficient to perform direct sequencing. CONCLUSION KRAS status in a primary site may be used for selecting patients who would benefit from anti-epidermal growth factor receptor therapy. However, KRAS status can be heterogeneous within a primary tumor, and thus different parts of such tumors should be examined for KRAS status to correctly predict the KRAS status in metastatic lesions.
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8
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Molinari F, Felicioni L, Buscarino M, De Dosso S, Buttitta F, Malatesta S, Movilia A, Luoni M, Boldorini R, Alabiso O, Girlando S, Soini B, Spitale A, Di Nicolantonio F, Saletti P, Crippa S, Mazzucchelli L, Marchetti A, Bardelli A, Frattini M. Increased detection sensitivity for KRAS mutations enhances the prediction of anti-EGFR monoclonal antibody resistance in metastatic colorectal cancer. Clin Cancer Res 2011; 17:4901-14. [PMID: 21632860 DOI: 10.1158/1078-0432.ccr-10-3137] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE KRAS mutations represent the main cause of resistance to anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MoAbs) in metastatic colorectal cancer (mCRC). We evaluated whether highly sensitive methods for KRAS investigation improve the accuracy of predictions of anti-EGFR MoAbs efficacy. EXPERIMENTAL DESIGN We retrospectively evaluated objective tumor responses in mCRC patients treated with cetuximab or panitumumab. KRAS codons 12 and 13 were examined by direct sequencing, MALDI-TOF MS, mutant-enriched PCR, and engineered mutant-enriched PCR, which have a sensitivity of 20%, 10%, 0.1%, and 0.1%, respectively. In addition, we analyzed KRAS codon 61, BRAF, and PIK3CA by direct sequencing and PTEN expression by immunohistochemistry. RESULTS In total, 111 patients were considered. Direct sequencing revealed mutations in codons 12 and 13 of KRAS in 43/111 patients (39%) and BRAF mutations in 9/111 (8%), with almost all of these occurring in nonresponder patients. Using highly sensitive methods, we identified up to 13 additional KRAS mutations compared with direct sequencing, all occurring in nonresponders. By analyzing PIK3CA and PTEN, we found that of these 13 patients, 7 did not show any additional alteration in the PI3K pathway. CONCLUSIONS The application of highly sensitive methods for the detection of KRAS mutations significantly improves the identification of mCRC patients resistant to anti-EGFR MoAbs.
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9
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Wu F, Shirahata A, Sakuraba K, Kitamura Y, Goto T, Saito M, Ishibashi K, Kigawa G, Nemoto H, Sanada Y, Hibi K. Downregulation of Mus81 as a novel prognostic biomarker for patients with colorectal carcinoma. Cancer Sci 2010; 102:472-7. [DOI: 10.1111/j.1349-7006.2010.01790.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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10
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Oosting J, Lips EH, van Eijk R, Eilers PHC, Szuhai K, Wijmenga C, Morreau H, van Wezel T. High-resolution copy number analysis of paraffin-embedded archival tissue using SNP BeadArrays. Genome Res 2007; 17:368-76. [PMID: 17267813 PMCID: PMC1800928 DOI: 10.1101/gr.5686107] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
High-density SNP microarrays provide insight into the genomic events that occur in diseases like cancer through their capability to measure both LOH and genomic copy numbers. Where currently available methods are restricted to the use of fresh frozen tissue, we now describe the design and validation of copy number measurements using the Illumina BeadArray platform and the application of this technique to formalin-fixed, paraffin-embedded (FFPE) tissue. In fresh frozen tissue from a set of colorectal tumors with numerous chromosomal aberrations, our method measures copy number patterns that are comparable to values from established platforms, like Affymetrix GeneChip and BAC array-CGH. Moreover, paired comparisons of fresh frozen and FFPE tissues showed nearly identical patterns of genomic change. We conclude that this method enables the use of paraffin-embedded material for research into both LOH and numerical chromosomal abnormalities. These findings make the large pathological archives available for genomic analysis, which could be especially relevant for hereditary disease where fresh material from affected relatives is rarely available.
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Affiliation(s)
- Jan Oosting
- Department of Pathology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands.
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11
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Abal M, Fsihi H, Bras-Gonçalves R, Doll A, Boyé K, Janssen KP, Alameda F, Reventós J, Louvard D, Magdelenat H, Poupon MF, Robine S. Heterogeneous Metastasis Efficiency of Isogenic Orthotopic Colon Cancer Xenografts Reveals Distinctive Gene Expression Profiles. Tumour Biol 2007; 28:139-50. [PMID: 17519533 DOI: 10.1159/000103009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Accepted: 04/24/2006] [Indexed: 11/19/2022] Open
Abstract
Hepatic and lung metastases are the leading causes of mortality and major indicators of aggressiveness in colorectal cancer. The underlying molecular mechanisms contributing to the development of metastasis are still unclear. Here, we designed a novel approach to explore gene expression profiles associated with metastasis in human colorectal cancer (hCRC). A series of ten isogenic tumors from three different hCRC models were orthotopically implanted into nude mice. In these series, we analyzed the contribution of dynamic heterogeneity, independently of any intrinsic gene expression program predictive of metastasis. When screened for the presence of disseminated tumor cells in the lung and liver, as the most common host tissues for hCRC metastases, both high- and low-metastatic efficient tumors were found among these isogenic orthotopic series. The metastasis-specific cDNA macroarray analysis of 96 genes, in both tumor populations for each of the three hCRC models, characterized a common differential gene expression within a small group of genes. Our results suggest that, independently of a gene expression profile predictive of metastasis, the progressive acquisition of additional alterations occurs during hCRC tumorigenesis. This dynamic process might determine tumor progression, namely the metastasis dissemination.
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Affiliation(s)
- Miguel Abal
- Transfer Laboratory, Institut Curie-CNRS, Paris, France
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12
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Poetsch M, Kleist B. Loss of heterozygosity at 15q21.3 correlates with occurrence of metastases in head and neck cancer. Mod Pathol 2006; 19:1462-9. [PMID: 16906132 DOI: 10.1038/modpathol.3800666] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Deletions on the long arm of chromosome 15 suggesting the presence of potential tumor suppressor genes have been found in several tumors including carcinomas of the colorectum, urinary bladder, breast, lung, and head and neck. Here, we analyzed allelic imbalance on chromosome 15q in head and neck carcinomas and corresponding lymph node metastases to define common regions of aberrations with potential involvement in development and progression of these tumors. We studied a panel of 40 polymorphic microsatellite markers, spanning 15q13-15q26, in 63 head and neck carcinomas and 38 lymph node metastases. Loss of heterozygosity (LOH) could be demonstrated in 34 primary tumors (54%) and 35 metastases (92%). Aberration mapping defined three minimum regions of aberrations: a region between the markers D15S106 and D15S1029 in 15q21.3 (estimated as 3.9 Mb; region 1) was affected in the majority of tumors, whereas two other regions between D15S144 and D15S1040 in 15q13.3-14 (estimated as 2.4 Mb; region 2) and between D15S130 and D15S985 in 15q26.2-26.3 (estimated as 4.7 Mb; region 3) were less often involved. Allelic loss in region 1 correlated with T stages (P=0.0029) and metastatic potential (P=0.0018). LOH in regions 2 and 3 occurred predominantly in metastases (P=0.0129 and P=0.0013, respectively). No correlation with grading, localization, or clinical outcome could be established for any of the affected regions. Our data hint at aberrations in 15q21.3 as a possible important characteristic for head and neck squamous cell carcinomas with risk of progression.
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Affiliation(s)
- Micaela Poetsch
- Institute of Forensic Medicine, University of Greifswald, Greifswald, Germany.
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Guenot D, Guérin E, Aguillon-Romain S, Pencreach E, Schneider A, Neuville A, Chenard MP, Duluc I, Du Manoir S, Brigand C, Oudet P, Kedinger M, Gaub MP. Primary tumour genetic alterations and intra-tumoral heterogeneity are maintained in xenografts of human colon cancers showing chromosome instability. J Pathol 2006; 208:643-52. [PMID: 16450341 DOI: 10.1002/path.1936] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Evaluation of the role of clonal heterogeneity in colon tumour sensitivity/resistance to drugs and/or in conferring metastatic potential requires an adequate experimental model in which the tumour cells maintain the initial genetic alterations and intra-tumoral heterogeneity through maintenance of the genetic clones present in the initial tumour. Therefore, we xenografted subcutaneously into nude mice seven human colonic tumours (from stages B1 to D) that showed chromosome instability and transplanted them sequentially for up to 14 passages. Maintenance after xenografting of the genetic alterations present in the initial tumours was scored by allelotype studies targeting 45 loci localized on 18 chromosomes. We show that xenografting does not alter the genetic or the histological profiles of the tumours even after 14 passages. Screening of the entire genome of one tumour by comparative genome hybridization also showed overall stability of the alterations between the initial and the xenografted tumour. In addition, intra-tumoral heterogeneity was maintained over time, suggesting that no clonal selection occurred in the nude mice. The observation that some loci showed partial allelic imbalance in the initial tumour but loss of heterozygosity after the first passage in nude mice when all the normal cells were lost may allow identification of interesting genetic defects that could be involved in tumour expansion. Thus, sequential xenografts of colon tumours will provide a powerful model for further study of tumour clonality and for the identification of genetic profiles responsible for differential resistance to therapeutic treatments. Our data also suggest that tumour expansion can result from alterations in several distinct genetic pathways.
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Affiliation(s)
- D Guenot
- Inserm, U682, Strasbourg F-67200 France; Univ Strasbourg, Strasbourg, F-67200 France.
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Losi L, Baisse B, Bouzourene H, Benhattar J. Evolution of intratumoral genetic heterogeneity during colorectal cancer progression. Carcinogenesis 2005; 26:916-22. [PMID: 15731168 DOI: 10.1093/carcin/bgi044] [Citation(s) in RCA: 142] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Evolution of intratumoral genetic heterogeneity during colorectal tumor progression has not been investigated so far. Multiple sample areas in colorectal adenocarcinoma at early and advanced stages and in metastases were studied for the well-known genetic alterations: K-ras and p53 point mutations and loss of heterozygosity (LOH) on chromosomes 5q and 18q. In primary colorectal cancers (CRCs), intratumoral genetic heterogeneity was more often observed in early than in advanced stages, at 90 and 67%, respectively. All but one of the advanced CRCs were composed of one predominant clone and other minor clones, whereas no predominant clone has been identified in half of the early cancers. At the early stage, the last events that were produced, the p53 mutation and LOH of 18q, were also the most heterogeneous. At the advanced stage, the LOH of 5q and 18q were the most frequent heterogeneous events (67 and 58%, respectively). The intratumoral heterogeneity for mutations was significantly reduced, from the early to the advanced stages (from 60 to 20% for K-ras and from 70 to 20% for p53). On the other hand, a quasi absence of intratumoral genetic heterogeneity was observed for K-ras and p53 in distant metastasis. In conclusion, colorectal adenocarcinomas are characterized by marked intratumoral genetic heterogeneity. A reduction of the intratumoral genetic heterogeneity for point mutations and a relative stability of the heterogeneity for allelic losses indicate that, during the progression of CRC, clonal selection and chromosome instability continue, while an increase cannot be proven.
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Affiliation(s)
- Lorena Losi
- Department of Pathology, University of Modena and Reggio Emilia, 4110 Modena, Italy
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Chapusot C, Martin L, Puig PL, Ponnelle T, Cheynel N, Bouvier AM, Rageot D, Roignot P, Rat P, Faivre J, Piard F. What is the best way to assess microsatellite instability status in colorectal cancer? Study on a population base of 462 colorectal cancers. Am J Surg Pathol 2005; 28:1553-9. [PMID: 15577673 DOI: 10.1097/00000478-200412000-00002] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The assessment of the microsatellite instability (MSI) status in colorectal cancers is presently warranted for three reasons: 1) as a screening tool for hereditary nonpolyposis colorectal cancer, 2) as a prognostic marker, and 3) as a potential predictive factor of chemotherapy response. The aim of this study was to evaluate, on a large scale with tissue samples coming from a number of different sources, the difficulties met with routine use of immunohistochemistry (IHC) and to determine if it really does offer an accurate alternative to PCR genotyping. Colorectal carcinomas from 462 consecutive patients resected in public or private hospitals were assessed for MSI status by two methods: MSI testing (with BAT-26 microsatellite) and IHC detection of hMLH1, hMSH2, and hMSH6 proteins. Of the 398 cancers tested, immunohistochemistry was noncontributory in 42 (10.5%), focal in 9 (2.3%), and discordant with the PCR results in 36 (9%). For these 87 cases, complementary analyses were performed to explain discrepancy. After additional IHC assay with modified processing protocols, 8 cases remained noncontributory, 2 focal, and 28 discordant: 18 microsatellite stability IHC/MSI PCR and 10 MSI IHC/microsatellite stability PCR. For these discordant cases, we performed a multiplex PCR assay on DNA extracted from the frozen sample and BAT-26 was amplified from DNA extracted from the paraffin blocks used for IHC. Four discordant cases were reclassified after PCR multiplex assay (3 as MSI and 1 as microsatellite stability). Five other cases displayed intratumoral heterogeneity and 19 remained discordant. The discrepancy could be partly explained by variable technical protocols of fixation in the different laboratories, leading to variations in staining quality and difficulties in IHC interpretation. This population-based study is the first one to show that IHC is not sensitive and specific enough to be used routinely. Immunohistochemistry analysis of MMR proteins must be performed in standardized conditions and interpreted by confirmed pathologists. It cannot replace PCR as long as protocols are not optimized and harmonized.
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Affiliation(s)
- C Chapusot
- Service d'Anatomie Pathologique, Dijon, Faculté de Médecine, Dijon, France.
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