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Zito Marino F, Bianco R, Accardo M, Ronchi A, Cozzolino I, Morgillo F, Rossi G, Franco R. Molecular heterogeneity in lung cancer: from mechanisms of origin to clinical implications. Int J Med Sci 2019; 16:981-989. [PMID: 31341411 PMCID: PMC6643125 DOI: 10.7150/ijms.34739] [Citation(s) in RCA: 99] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 05/05/2019] [Indexed: 12/13/2022] Open
Abstract
Molecular heterogeneity is a frequent event in cancer responsible of several critical issues in diagnosis and treatment of oncologic patients. Lung tumours are characterized by high degree of molecular heterogeneity associated to different mechanisms of origin including genetic, epigenetic and non-genetic source. In this review, we provide an overview of recognized mechanisms underlying molecular heterogeneity in lung cancer, including epigenetic mechanisms, mutant allele specific imbalance, genomic instability, chromosomal aberrations, tumor mutational burden, somatic mutations. We focus on the role of spatial and temporal molecular heterogeneity involved in therapeutic implications in lung cancer patients.
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Affiliation(s)
| | - Roberto Bianco
- Department of Clinical Medicine and Surgery, Oncology Division, University of Naples Federico II, Naples, Italy
| | - Marina Accardo
- Pathology Unit, University of Campania “L. Vanvitelli”, Naples, Italy
| | - Andrea Ronchi
- Pathology Unit, University of Campania “L. Vanvitelli”, Naples, Italy
| | | | - Floriana Morgillo
- Medical Oncology, Department of Precision Medicine, University of Campania “L. Vanvitelli”, Naples, Italy
| | - Giulio Rossi
- Pathology Unit, Hospital S. Maria delle Croci, Azienda Romagna, Ravenna, Italy
| | - Renato Franco
- Pathology Unit, University of Campania “L. Vanvitelli”, Naples, Italy
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Syahruddin E, Wulandari L, Sri Muktiati N, Rima A, Soeroso N, Ermayanti S, Levi M, Hidajat H, Widjajahakim G, Utomo ARH. Uncommon EGFR mutations in cytological specimens of 1,874 newly diagnosed Indonesian lung cancer patients. LUNG CANCER-TARGETS AND THERAPY 2018; 9:25-34. [PMID: 29615847 PMCID: PMC5870662 DOI: 10.2147/lctt.s154116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Purpose We aimed to evaluate the distribution of individual epidermal growth factor receptor (EGFR) mutation subtypes found in routine cytological specimens. Patients and methods A retrospective audit was performed on EGFR testing results of 1,874 consecutive cytological samples of newly diagnosed or treatment-naïve Indonesian lung cancer patients (years 2015–2016). Testing was performed by ISO15189 accredited central laboratory. Results Overall test failure rate was 5.1%, with the highest failure (7.1%) observed in pleural effusion and lowest (1.6%) in needle aspiration samples. EGFR mutation frequency was 44.4%. Tyrosine kinase inhibitor (TKI)-sensitive common EGFR mutations (ins/dels exon 19, L858R) and uncommon mutations (G719X, T790M, L861Q) contributed 57.1% and 29%, respectively. Approximately 13.9% of mutation-positive patients carried a mixture of common and uncommon mutations. Women had higher EGFR mutation rate (52.9%) vs men (39.1%; p<0.05). In contrast, uncommon mutations conferring either TKI responsive (G719X, L861Q) or TKI resistance (T790M, exon 20 insertions) were consistently more frequent in men than in women (67.3% vs 32.7% or 69.4% vs 30.6%; p<0.05). Up to 10% EGFR mutation–positive patients had baseline single mutation T790M, exon 20 insertion, or in coexistence with TKI-sensitive mutations. Up to 9% patients had complex or multiple EGFR mutations, whereby 48.7% patients harbored TKI-resistant mutations. One patient presented third-generation TKI-resistant mutation L792F simultaneously with T790M. Conclusion Routine diagnostic cytological techniques yielded similar success rate to detect EGFR mutations. Uncommon EGFR mutations were frequent events in Indonesian lung cancer patients.
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Affiliation(s)
- Elisna Syahruddin
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Universitas Indonesia.,Department of Pulmonology, Persahabatan Hospital, Jakarta, Indonesia
| | - Laksmi Wulandari
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Universitas Airlangga - Soetomo Hospital, Surabaya, Indonesia
| | - Nunuk Sri Muktiati
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Universitas Brawijaya - Saiful Anwar General Hospital, Malang, Indonesia
| | - Ana Rima
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Universitas Sebelas Maret, Dr. Moewardi General Hospital, Surakarta, Indonesia
| | - Noni Soeroso
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, University of Sumatera Utara, Adam Malik General Hospital, Medan, Indonesia
| | - Sabrina Ermayanti
- Department of Pulmonology and Respiratory Medicine, Faculty of Medicine, Andalas University, M. Djamil Hospital, Padang, Indonesia
| | - Michael Levi
- Kalbe Genomics Laboratory, Division of Molecular Pathology Testing Service, PT Bifarma Adiluhung
| | - Heriawaty Hidajat
- Department of Pulmonology, Persahabatan Hospital, Jakarta, Indonesia
| | - Grace Widjajahakim
- Kalbe Genomics Laboratory, Division of Molecular Pathology Testing Service, PT Bifarma Adiluhung
| | - Ahmad Rusdan Handoyo Utomo
- Stem Cell and Cancer Institute, Cancer Diagnostic Research Division, PT Kalbe Farma Tbk, Jakarta, Indonesia
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Mutant allele specific imbalance in oncogenes with copy number alterations: Occurrence, mechanisms, and potential clinical implications. Cancer Lett 2016; 384:86-93. [PMID: 27725226 DOI: 10.1016/j.canlet.2016.10.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 10/03/2016] [Accepted: 10/03/2016] [Indexed: 01/16/2023]
Abstract
Mutant allele specific imbalance (MASI) was initially coined to describe copy number alterations associated with the mutant allele of an oncogene. The copy number gain (CNG) specific to the mutant allele can be readily observed in electropherograms. With the development of genome-wide analyses at base-pair resolution with copy number counts, we can now further differentiate MASI into those with CNG, with copy neutral alteration (also termed acquired uniparental disomy; UPD), or with loss of heterozygosity (LOH) due to the loss of the wild-type (WT) allele. Here we summarize the occurrence of MASI with CNG, aUPD, or MASI with LOH in some major oncogenes (such as EGFR, KRAS, PIK3CA, and BRAF). We also discuss how these various classifications of MASI have been demonstrated to impact tumorigenesis, progression, metastasis, prognosis, and potentially therapeutic responses in cancer, notably in lung, colorectal, and pancreatic cancers.
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Significance of EGFR signaling pathway genetic alterations in radically resected non-small cell lung cancers from a Polish cohort. One institutional study. Adv Med Sci 2015; 60:277-86. [PMID: 26118982 DOI: 10.1016/j.advms.2015.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 05/28/2015] [Accepted: 05/29/2015] [Indexed: 12/12/2022]
Abstract
PURPOSE We evaluated the distribution and clinical impact of EGFR, KRAS and HER2 copy number gains and EGFR, KRAS and BRAF activating mutations in resected non-small cell lung cancers (NSCLCs) from 151 Polish patients. MATERIALS AND METHODS Quantitative PCR and DNA sequencing were used for copy number evaluation and mutational analysis, respectively. RESULTS An increased EGFR CN was found in 21.2% of the tumors, more commonly of the non-squamous histology (P=0.029), larger in size (P=0.004) and those obtained from women (P=0.040). HER2 copy gain was observed in 21.8% of the patients, more frequently with lymph node metastases (P=0.048) and stage IIIA disease (P=0.061). KRAS gain was found in 29.3% of the tumors, and was not associated with patients' clinicopathological features. No BRAF mutations were found. EGFR and KRAS mutation frequency and associations with clinicopathological characteristics did not differ significantly from those previously described for the NSCLC patients of Caucasian ethnicity. Strong associations existed between most of the analyzed alterations. In the multivariate model, EGFR mutations constituted an independent prognostic factor of the disease recurrence in adenocarcinoma patients (HR 7.20; 95%CI 1.31-39.48; P=0.023), while an increased EGFR copy number tended to indicate a shorter overall survival (HR 4.85; 95%CI 0.92-25.58; P=0.062). CONCLUSIONS EGFR pathway genes alterations are frequent in NSCLCs from Polish patients and have a prognostic potential for patients' clinical outcome after a curative tumor resection. Gene CN evaluation by quantitative PCR provides comparable results and enables assay standardization, yet the optimal scoring system needs to be developed.
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Malapelle U, Vatrano S, Russo S, Bellevicine C, de Luca C, Sgariglia R, Rocco D, de Pietro L, Riccardi F, Gobbini E, Righi L, Troncone G. EGFR mutant allelic-specific imbalance assessment in routine samples of non-small cell lung cancer. J Clin Pathol 2015; 68:739-41. [PMID: 26047622 DOI: 10.1136/jclinpath-2015-203101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 05/18/2015] [Indexed: 11/03/2022]
Abstract
In non-small cell lung cancer (NSCLC), the epidermal growth factor receptor (EGFR) gene may undergo both mutations and copy number gains. EGFR mutant allele-specific imbalance (MASI) occurs when the ratio of mutant-to-wild-type alleles increases significantly. In this study, by using a previously validated microfluidic-chip-based technology, EGFR-MASI occurred in 25/67 mutant cases (37%), being more frequently associated with EGFR exon 19 deletions (p=0.033). In a subset of 49 treated patients, we assessed whether MASI is a modifier of anti-EGFR treatment benefit. The difference in progression-free survival and overall survival between EGFR-MASI-positive and EGFR-MASI-negative groups of patients did not show a statistical significance. In conclusion, EGFR-MASI is a significant event in NSCLC, specifically associated with EGFR exon 19 deletions. However, EGFR-MASI does not seem to play a role in predicting the response to first-generation EGFR small molecules inhibitors.
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Affiliation(s)
- Umberto Malapelle
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Simona Vatrano
- Department of Oncology, University of Turin at San Luigi Hospital, Turin, Italy
| | - Stefania Russo
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Claudio Bellevicine
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Caterina de Luca
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Roberta Sgariglia
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Danilo Rocco
- Department of Oncology, Azienda Ospedaliera dei Colli, Naples, Italy
| | - Livia de Pietro
- Department of Oncology, Azienda Ospedaliera dei Colli, Naples, Italy
| | - Fernando Riccardi
- Department of Oncology, Antonio Cardarelli-Azienda Ospedaliera di Rilievo Nazionale, Naples, Italy
| | - Elisa Gobbini
- Department of Oncology, University of Turin at San Luigi Hospital, Turin, Italy
| | - Luisella Righi
- Department of Oncology, University of Turin at San Luigi Hospital, Turin, Italy
| | - Giancarlo Troncone
- Department of Public Health, University of Naples Federico II, Naples, Italy
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Malapelle U, Sgariglia R, De Stefano A, Bellevicine C, Vigliar E, de Biase D, Sepe R, Pallante P, Carlomagno C, Tallini G, Troncone G. KRAS mutant allele-specific imbalance (MASI) assessment in routine samples of patients with metastatic colorectal cancer. J Clin Pathol 2015; 68:265-9. [PMID: 25609577 DOI: 10.1136/jclinpath-2014-202761] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AIMS Patients with colorectal cancer harbouring KRAS mutations do not respond to antiepidermal growth factor receptor (anti-EGFR) therapy. Community screening for KRAS mutation selects patients for treatment. When a KRAS mutation is identified by direct sequencing, mutant and wild type alleles are seen on the sequencing electropherograms. KRAS mutant allele-specific imbalance (MASI) occurs when the mutant allele peak is higher than the wild type one. The aims of this study were to verify the rate and tissue distribution of KRAS MASI as well as its clinical relevance. METHODS A total of 437 sequencing electropherograms showing KRAS exon 2 mutation was reviewed and in 30 cases next generation sequencing (NGS) was also carried out. Five primary tumours were extensively laser capture microdissected to investigated KRAS MASI tissue spatial distribution. KRAS MASI influence on the overall survival was evaluated in 58 patients. In vitro response to anti-EGFR therapy in relation to different G13D KRAS MASI status was also evaluated. RESULTS On the overall, KRAS MASI occurred in 58/436 cases (12.8%), being more frequently associated with G13D mutation (p=0.05) and having a heterogeneous tissue distribution. KRAS MASI detection by Sanger Sequencing and NGS showed 94% (28/30) concordance. The longer overall survival of KRAS MASI negative patients did not reach statistical significance (p=0.08). In cell line model G13D KRAS MASI conferred resistance to cetuximab treatment. CONCLUSIONS KRAS MASI is a significant event in colorectal cancer, specifically associated with G13D mutation, and featuring a heterogeneous spatial distribution, that may have a role to predict the response to EGFR inhibitors. The foreseen implementation of NGS in community KRAS testing may help to define KRAS MASI prognostic and predictive significance.
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Affiliation(s)
- Umberto Malapelle
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Roberta Sgariglia
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Alfonso De Stefano
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Napoles, Italy
| | - Claudio Bellevicine
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Elena Vigliar
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Dario de Biase
- Department of Medicine (DIMES)-Anatomic Pathology Unit, Bellaria Hospital, University of Bologna, Bologna, Italy
| | - Romina Sepe
- CNR/IEOS, Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy Department of Molecular Medicine and Medical Biotechnology (DMMBM), University of Naples Federico II, Naples, Italy
| | - Pierlorenzo Pallante
- CNR/IEOS, Institute of Experimental Endocrinology and Oncology, National Research Council, Naples, Italy Department of Molecular Medicine and Medical Biotechnology (DMMBM), University of Naples Federico II, Naples, Italy
| | - Chiara Carlomagno
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Napoles, Italy
| | - Giovanni Tallini
- Department of Medicine (DIMES)-Anatomic Pathology Unit, Bellaria Hospital, University of Bologna, Bologna, Italy
| | - Giancarlo Troncone
- Department of Public Health, University of Naples Federico II, Naples, Italy
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The use of mutation-specific antibodies in predicting the effect of EGFR-TKIs in patients with non-small-cell lung cancer. J Cancer Res Clin Oncol 2014; 140:849-57. [DOI: 10.1007/s00432-014-1618-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 02/08/2014] [Indexed: 11/24/2022]
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KRAS mutant allele-specific imbalance is associated with worse prognosis in pancreatic cancer and progression to undifferentiated carcinoma of the pancreas. Mod Pathol 2013; 26:1346-54. [PMID: 23599154 PMCID: PMC4128625 DOI: 10.1038/modpathol.2013.71] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/18/2013] [Accepted: 02/19/2013] [Indexed: 12/19/2022]
Abstract
KRAS codon 12 mutations are present in about 90% of ductal adenocarcinomas and in undifferentiated carcinomas of the pancreas. The role of KRAS copy number changes and resulting KRAS mutant allele-specific imbalance (MASI) in ductal adenocarcinoma (n=94), and its progression into undifferentiated carcinoma of the pancreas (n=25) was studied by direct sequencing and KRAS fluorescence in situ hybridization (FISH). Semi-quantitative evaluation of sequencing electropherograms showed KRAS MASI (ie, mutant allele peak higher than or equal to the wild-type allele peak) in 22 (18.4%) cases. KRAS FISH (performed on 45 cases) revealed a trend for more frequent KRAS amplification among cases with KRAS MASI (7/20, 35% vs 3/25, 12%, P=0.08). KRAS amplification by FISH was seen only in undifferentiated carcinomas (10/24, 42% vs 0/21 pancreatic ductal adenocarcinoma, 0%, P=0.0007). In 6 of 11 cases with both undifferentiated and well-differentiated components, transition to undifferentiated carcinoma was associated with an increase in KRAS copy number, due to amplification and/or chromosome 12 hyperploidy. Pancreatic carcinomas with KRAS MASI (compared to those without MASI) were predominantly undifferentiated (16/22, 73% vs 9/97, 9%, P<0.001), more likely to present at clinical stage IV (5/22, 23% vs 7/97, 7%, P=0.009), and were associated with shorter overall survival (9 months, 95% confidence interval, 5-13, vs 22 months, 95% confidence interval, 17-27; P=0.015) and shorter disease-free survival (5 months, 95% confidence interval, 2-8 vs 13 months, 95% confidence interval, 10-16; P=0.02). Our findings suggest that in a subset of ductal adenocarcinomas, KRAS MASI correlates with the progression to undifferentiated carcinoma of the pancreas.
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Malapelle U, Russo S, Pepe F, Sgariglia R, De Luca C, Bellevicine C, Pallante P, Troncone G. EGFR mutation detection by microfluidic technology: a validation study. J Clin Pathol 2013; 66:982-4. [PMID: 23794480 DOI: 10.1136/jclinpath-2013-201730] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Advanced non-small cell lung cancer samples are tested for epidermal growth factor receptor (EGFR) gene mutations. Their detection by direct sequencing is time-consuming. Conversely, the length analysis of fluorescently labelled PCR products is easier. To avoid labelled primers and the automated capillary electrophoresis apparatus, we validated a fast and sensitive chip-based microfluidic technology. The limit of detection of fragment length assay on microfluidic device was 5%, more sensitive than direct sequencing (12.5%). The novel methodology showed high accuracy in the analysis of samples whose mutational status was known. The accuracy in quantifying mutated alleles (mA) was evaluated by PCR products subcloning; the mA% provided by direct sequencing of subcloned PCR products showed a close correlation with the mA% provided by the microfluidic technology for both exon 19 (R(2)=0.9) and 21 (R(2)=0.9). Microfluidic-based on-chip electrophoresis makes EGFR testing more rapid, sensitive and cost-effective.
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Affiliation(s)
- Umberto Malapelle
- Dipartimento di Sanità Pubblica, Università di Napoli Federico II, , Napoli, Italia
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Villaruz LC, Socinski MA, Cunningham DE, Chiosea SI, Burns TF, Siegfried JM, Dacic S. The prognostic and predictive value of KRAS oncogene substitutions in lung adenocarcinoma. Cancer 2013; 119:2268-74. [PMID: 23526491 DOI: 10.1002/cncr.28039] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/08/2013] [Accepted: 02/13/2013] [Indexed: 11/07/2022]
Abstract
BACKGROUND The prognostic and therapeutic implications of the spectrum of v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) oncogene substitutions in lung cancer remain poorly understood. The objective of this study was to determine whether KRAS oncogene substitutions differed with regard to prognosis or predictive value in lung adenocarcinoma. METHODS KRAS oncogene substitutions and mutant allele-specific imbalance (MASI) were determined in patients with lung adenocarcinoma, and the associations with overall survival (OS), recurrence-free survival (RFS), and chemotherapy interactions were assessed. RESULTS KRAS mutational analysis was performed on 988 lung adenocarcinomas, and 318 KRAS mutations were identified. In this predominantly early stage cohort (78.6% of patients had stage I-III disease), OS and RFS did not differ according to the type of KRAS substitution (OS, P = .612; RFS, P = .089). There was a trend toward better OS in the subset of patients with KRAS codon 13 mutations (P = .052), but that trend was not significant in multivariate analysis (P = .076). RFS did not differ according to codon type in univariate analysis (P = .322). There was a marked difference in RFS based on the presence of MASI in univariate analysis (P = .004) and multivariate analysis (P = .009). A test for interaction was performed to determine whether the effect of chemotherapy on OS and RFS differed based on KRAS substitution type, codon type, or the presence of MASI. That test indicated that there were no differences in the effects of chemotherapy for any of variables examined. CONCLUSIONS KRAS codon 13 mutations and MASI were identified as candidate biomarkers for prognosis, and it may be useful to incorporate them into prospective studies evaluating novel therapies in KRAS-mutant lung adenocarcinoma.
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Affiliation(s)
- Liza C Villaruz
- University of Pittsburgh Cancer Institute, School of Medicine/Hematology-Oncology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Hartman DJ, Davison JM, Foxwell TJ, Nikiforova MN, Chiosea SI. Mutant allele-specific imbalance modulates prognostic impact of KRAS mutations in colorectal adenocarcinoma and is associated with worse overall survival. Int J Cancer 2012; 131:1810-7. [PMID: 22290300 DOI: 10.1002/ijc.27461] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 01/14/2012] [Accepted: 01/18/2012] [Indexed: 01/15/2023]
Abstract
The prognostic impact of distinct KRAS mutations in colorectal carcinomas is not fully characterized. We hypothesized that the prognostic impact of KRAS mutations is modulated by KRAS mutant allele-specific imbalance (MASI). KRAS MASI was assessed by sequencing electropherograms in KRAS-mutated colorectal carcinomas (N = 394, prospectively tested). The mechanism of KRAS MASI was studied by fluorescence in situ hybridization (FISH; N = 50). FISH showed that KRAS MASI developed by chromosome 12 hyperploidy (9/18, 50%) or KRAS amplification (1/18, 5.5%). KRAS MASI was more common in tumors with KRAS codon 13 than with codon 12 mutations [24/81, 30% vs. 54/313, 17%; odds ratio (OR), 2.0, 95% confidence interval (CI), 1.2-3.5; p = 0.01]. KRAS MASI was correlated with overall survival (N = 358, median follow-up = 21 months). In a multivariate analysis, KRAS codon 13 MASI was an independent adverse prognostic factor (compared to codon 13 mutants without MASI combined with all codon 12 mutants; adjusted hazard ratio, 2.2, 95% CI: 1.2-3.9; p = 0.01). KRAS MASI arises through chromosome 12 hyperploidy or KRAS amplification and, when affects KRAS codon 13, is associated with worse overall survival.
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Affiliation(s)
- D J Hartman
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Chiosea SI, Sherer CK, Jelic T, Dacic S. KRAS mutant allele-specific imbalance in lung adenocarcinoma. Mod Pathol 2011; 24:1571-7. [PMID: 21743433 DOI: 10.1038/modpathol.2011.109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The significance of KRAS mutant allele-specific imbalance (MASI) in lung adenocarcinomas is unknown. KRAS MASI was defined as predominance of the mutant allele over the wild-type allele. We assessed the frequency of KRAS MASI by comparing peak heights of mutant and wild-type alleles on sequencing electropherograms and by KRAS fluorescence in situ hybridization (FISH). A review of sequencing electropherograms of 207 KRAS-mutated lung adenocarcinomas demonstrated 23 (11%) cases with the mutant allele peak higher than the wild-type allele peak and 15 (7%) cases with the mutant allele peak equal to the wild-type allele peak. Of 17 cases with the mutant allele peak higher or equal to the wild-type allele peak, 8 (47%) showed KRAS amplification by FISH. KRAS FISH analysis of 36 KRAS-mutated lung adenocarcinomas with the mutant allele peak lower than the wild-type allele peak, 21 KRAS and EGFR wild-type and 16 EGFR-mutated adenocarcinomas showed no KRAS amplification. KRAS MASI was associated with selective amplification of the KRAS mutant allele (P<0.001). Patients with KRAS MASI showed worse overall survival. The cumulative proportion surviving at 17 months for KRAS MASI group was 35% compared with 84.1% for patients with KRAS mutant allele peak lower than wild-type allele peak (P=0.012). The adverse prognostic significance of KRAS MASI was independent of clinical stage and was maintained among stage I patients. The detection of KRAS MASI in lung adenocarcinomas by sequencing electropherograms may identify patients with more aggressive disease.
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Affiliation(s)
- Simion I Chiosea
- Department of Pathology, University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, PA, USA.
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