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Abstract
Allele-specific competitive blocker PCR (ACB-PCR) is a sensitive and quantitative approach for the selective amplification of a specific base substitution. Using the ACB-PCR technique, hotspot cancer-driver mutations (tumor-relevant mutations in oncogenes and tumor suppressor genes, which confer a selective growth advantage) are being developed as quantitative biomarkers of cancer risk. ACB-PCR employs a mutant-specific primer (with a 3'-penultimate mismatch relative to the mutant DNA sequence, but a double 3'-terminal mismatch relative to the wild-type DNA sequence) to selectively amplify rare mutant DNA molecules. A blocker primer having a non-extendable 3'-end and a 3'-penultimate mismatch relative to the wild-type DNA sequence, but a double 3'-terminal mismatch relative to the mutant DNA sequence is included in ACB-PCR to selectively repress amplification from abundant wild-type molecules. Consequently, ACB-PCR can quantify the level of a single base pair substitution mutation in a DNA population when present at a mutant:wild-type ratio of 1 × 10-5 or greater. Quantification of rare mutant alleles is achieved by parallel analysis of unknown samples and mutant fraction (MF) standards (defined mixtures of mutant and wild-type DNA sequences). The ability to quantify specific mutations with known association to cancer has several important applications in evaluating the carcinogenic potential of chemical exposures in rodent models. Further, the measurement of cancer-driver mutant subpopulations is important for precision cancer treatment (selecting the most appropriate targeted therapy and predicting the development of therapeutic resistance). This chapter provides a step-by-step description of the ACB-PCR methodology as it has been used to measure human PIK3CA codon 1047, CAT→CGT (H1047R) mutation.
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Myers MB, McKim KL, Banda M, George NI, Parsons BL. Low-Frequency Mutational Heterogeneity of Invasive Ductal Carcinoma Subtypes: Information to Direct Precision Oncology. Int J Mol Sci 2019; 20:E1011. [PMID: 30813596 PMCID: PMC6429455 DOI: 10.3390/ijms20051011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 12/12/2022] Open
Abstract
Information regarding the role of low-frequency hotspot cancer-driver mutations (CDMs) in breast carcinogenesis and therapeutic response is limited. Using the sensitive and quantitative Allele-specific Competitor Blocker PCR (ACB-PCR) approach, mutant fractions (MFs) of six CDMs (PIK3CA H1047R and E545K, KRAS G12D and G12V, HRAS G12D, and BRAF V600E) were quantified in invasive ductal carcinomas (IDCs; including ~20 samples per subtype). Measurable levels (i.e., ≥ 1 × 10-5, the lowest ACB-PCR standard employed) of the PIK3CA H1047R, PIK3CA E545K, KRAS G12D, KRAS G12V, HRAS G12D, and BRAF V600E mutations were observed in 34/81 (42%), 29/81 (36%), 51/81 (63%), 9/81 (11%), 70/81 (86%), and 48/81 (59%) of IDCs, respectively. Correlation analysis using available clinicopathological information revealed that PIK3CA H1047R and BRAF V600E MFs correlate positively with maximum tumor dimension. Analysis of IDC subtypes revealed minor mutant subpopulations of critical genes in the MAP kinase pathway (KRAS, HRAS, and BRAF) were prevalent across IDC subtypes. Few triple-negative breast cancers (TNBCs) had appreciable levels of PIK3CA mutation, suggesting that individuals with TNBC may be less responsive to inhibitors of the PI3K/AKT/mTOR pathway. These results suggest that low-frequency hotspot CDMs contribute significantly to the intertumoral and intratumoral genetic heterogeneity of IDCs, which has the potential to impact precision oncology approaches.
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Affiliation(s)
- Meagan B Myers
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Karen L McKim
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Malathi Banda
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Nysia I George
- Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
| | - Barbara L Parsons
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.
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Dzobo K, Senthebane DA, Thomford NE, Rowe A, Dandara C, Parker MI. Not Everyone Fits the Mold: Intratumor and Intertumor Heterogeneity and Innovative Cancer Drug Design and Development. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2019; 22:17-34. [PMID: 29356626 DOI: 10.1089/omi.2017.0174] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Disruptive innovations in medicine are game-changing in nature and bring about radical shifts in the way we understand human diseases, their treatment, and/or prevention. Yet, disruptive innovations in cancer drug design and development are still limited. Therapies that cure all cancer patients are in short supply or do not exist at all. Chief among the causes of this predicament is drug resistance, a mechanism that is much more dynamic than previously understood. Drug resistance has limited the initial success experienced with biomarker-guided targeted therapies as well. A major contributor to drug resistance is intratumor heterogeneity. For example, within solid tumors, there are distinct subclones of cancer cells, presenting profound complexity to cancer treatment. Well-known contributors to intratumor heterogeneity are genomic instability, the microenvironment, cellular genotype, cell plasticity, and stochastic processes. This expert review explains that for oncology drug design and development to be more innovative, we need to take into account intratumor heterogeneity. Initially thought to be the preserve of cancer cells, recent evidence points to the highly heterogeneous nature and diverse locations of stromal cells, such as cancer-associated fibroblasts (CAFs) and cancer-associated macrophages (CAMs). Distinct subpopulations of CAFs and CAMs are now known to be located immediately adjacent and distant from cancer cells, with different subpopulations exerting different effects on cancer cells. Disruptive innovation and precision medicine in clinical oncology do not have to be a distant reality, but can potentially be achieved by targeting these spatially separated and exclusive cancer cell subclones and CAF subtypes. Finally, we emphasize that disruptive innovations in drug discovery and development will likely come from drugs whose effect is not necessarily tumor shrinkage.
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Affiliation(s)
- Kevin Dzobo
- 1 International Centre for Genetic Engineering and Biotechnology (ICGEB) , Cape Town, South Africa .,2 Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Cape Town, South Africa
| | - Dimakatso Alice Senthebane
- 1 International Centre for Genetic Engineering and Biotechnology (ICGEB) , Cape Town, South Africa .,2 Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Cape Town, South Africa
| | - Nicholas Ekow Thomford
- 3 Pharmacogenetics Research Group, Division of Human Genetics, Department of Pathology, Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town , Cape Town, South Africa
| | - Arielle Rowe
- 1 International Centre for Genetic Engineering and Biotechnology (ICGEB) , Cape Town, South Africa
| | - Collet Dandara
- 3 Pharmacogenetics Research Group, Division of Human Genetics, Department of Pathology, Faculty of Health Sciences, Institute of Infectious Diseases and Molecular Medicine, University of Cape Town , Cape Town, South Africa
| | - M Iqbal Parker
- 2 Division of Medical Biochemistry, Department of Integrative Biomedical Sciences, Faculty of Health Sciences, Institute of Infectious Disease and Molecular Medicine, University of Cape Town , Cape Town, South Africa
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Kordiak J, Szemraj J, Grabska-Kobylecka I, Bialasiewicz P, Braun M, Kordek R, Nowak D. Intratumor heterogeneity and tissue distribution of KRAS mutation in non-small cell lung cancer: implications for detection of mutated KRAS oncogene in exhaled breath condensate. J Cancer Res Clin Oncol 2018; 145:241-251. [PMID: 30368666 PMCID: PMC6325989 DOI: 10.1007/s00432-018-2779-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 10/23/2018] [Indexed: 12/15/2022]
Abstract
Purpose Mutated KRAS oncogene in exhaled breath condensate (EBC) can be a genetic marker of non-small cell lung cancer (NSCLC). However, a possibility of inhomogeneous distribution in cancer tissue and intratumor heterogeneity of KRAS mutation may decrease its significance. We investigated a status of KRAS point mutation and its sequence at codon 12 in 51 NSCLC patients after tumor resection. The comparison of KRAS mutation status between EBC–DNA and cancer tissue was performed in 19 cases. Methods Five cancer tissue samples from disparate tumor regions and one from normal lung were harvested at surgery. EBC was collected for DNA analysis the previous day. KRAS point mutations at codon 12 were detected using mutant-enriched PCR technique and pyrosequenced. Results Forty-six cancers revealed concordance of KRAS mutation status: 27 contained mutated KRAS and 19 had only wild KRAS. Five NSCLCs revealed inhomogeneous distribution of KRAS mutation. Two different mutations were found in 14 NSCLCs and the most frequent one was G12D and G12V (n = 8). No mutated KRAS was found in normal lung. The concordance ratios of KRAS sequence in codon 12 between EBC–DNA and cancer were 18/19 for NSCLC patients and 11/12 for KRAS mutation positive NSCLC. Conclusions Intratumor heterogeneity and inhomogeneous distribution of KRAS point mutation in codon 12 in cancer tissue can occur in NSCLCs. There was a high accordance between KRAS mutation status in EBC–DNA and cancer tissue in NSCLC patients what suggests usefulness of monitoring KRAS mutation in EBC–DNA as a biomarker of NSCLC.
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Affiliation(s)
- Jacek Kordiak
- Department of Chest Surgery, Oncologic and General Surgery, Medical University of Lodz, University Hospital No. 2, Zeromskiego St. 113, 91-647, Lodz, Poland
| | - Janusz Szemraj
- Department of Medical Biochemistry, Medical University of Lodz, Mazowiecka St. 6/8, 92-215, Lodz, Poland
| | - Izabela Grabska-Kobylecka
- Department of Clinical Physiology, Medical University of Lodz, Mazowiecka St. 6/8, 92-215, Lodz, Poland
| | - Piotr Bialasiewicz
- Department of Sleep Medicine and Metabolic Disorders, Medical University of Lodz, Mazowiecka St. 6/8, 92-215, Lodz, Poland
| | - Marcin Braun
- Department of Pathology, Medical University of Lodz, Pomorska St. 251, 92-215, Lodz, Poland
| | - Radzisław Kordek
- Department of Pathology, Medical University of Lodz, Pomorska St. 251, 92-215, Lodz, Poland
| | - Dariusz Nowak
- Department of Clinical Physiology, Medical University of Lodz, Mazowiecka St. 6/8, 92-215, Lodz, Poland.
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Li G, Guo X, Chen M, Tang L, Jiang H, Day JX, Xie Y, Peng L, Xu X, Li J, Wang S, Xiao Z, Dai L, Wang J. Prevalence and spectrum of AKT1, PIK3CA, PTEN and TP53 somatic mutations in Chinese breast cancer patients. PLoS One 2018; 13:e0203495. [PMID: 30212483 PMCID: PMC6136723 DOI: 10.1371/journal.pone.0203495] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/17/2018] [Indexed: 12/29/2022] Open
Abstract
Breast cancer, one of the most frequently occurring cancers worldwide, is the leading cause of cancer-related death among women. AKT1, PIK3CA, PTEN and TP53 mutations were common observed in breast cancer representing potential clinical biomarkers for cancer classification and treatment. A comprehensive knowledge of AKT1, PIK3CA, PTEN and TP53 mutations in breast cancer was still insufficient in Chinese population. In this study, the complete coding regions and exon-intron boundaries of AKT1, PIK3CA, PTEN and TP53 genes were sequenced in paired breast tumor and normal tissues from 313 Chinese breast cancer patients using microfluidic PCR-based target enrichment and next-generation sequencing technology. Total 120 somatic mutations were identified in 190 of the 313 patients (60.7%), with the mutation frequency of AKT1 as 3.2%, PIK3CA as 36.4%, PTEN as 4.8%, and TP53 as 33.9%. Among these mutations, 1 in PIK3CA (p.I69N), 3 in PTEN (p.K62X, c.635-12_636delTTAACCATGCAGAT and p.N340IfsTer4) and 5 in TP53 (p.Q136AfsTer5, p.K139_P142del, p.Y234dup, p.V274LfsTer31 and p.N310TfsTer35) were novel. Notably, PIK3CA somatic mutations were significantly associated with ER-positive or PR-positive tumors. TP53 somatic mutations were significantly associated with ER-negative, PR-negative, HER2-positive, BRCA1 mutation, Ki67 high expression and basal-like tumors. Our findings provided a comprehensive mutation profiling of AKT1, PIK3CA, PTEN and TP53 genes in Chinese breast cancer patients, which have potential implications in clinical management.
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Affiliation(s)
- Guoli Li
- School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Xinwu Guo
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Ming Chen
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Lili Tang
- Department of Breast Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hui Jiang
- School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Julia X. Day
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Yueliang Xie
- School of Life Sciences, Central South University, Changsha, Hunan, China
| | - Limin Peng
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Xunxun Xu
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Jinliang Li
- Sanway Gene Technology Inc., Changsha, Hunan, China
| | - Shouman Wang
- Department of Breast Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhi Xiao
- Department of Breast Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Lizhong Dai
- Sanway Gene Technology Inc., Changsha, Hunan, China
- Research Center for Technologies in Nucleic Acid-Based Diagnostics, Changsha, Hunan, China
- Research Center for Technologies in Nucleic Acid-Based Diagnostics and Therapeutics, Changsha, Hunan, China
| | - Jun Wang
- School of Life Sciences, Central South University, Changsha, Hunan, China
- Sanway Gene Technology Inc., Changsha, Hunan, China
- * E-mail:
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Myers MB, Banda M, McKim KL, Wang Y, Powell MJ, Parsons BL. Breast Cancer Heterogeneity Examined by High-Sensitivity Quantification of PIK3CA, KRAS, HRAS, and BRAF Mutations in Normal Breast and Ductal Carcinomas. Neoplasia 2016; 18:253-63. [PMID: 27108388 PMCID: PMC4840288 DOI: 10.1016/j.neo.2016.03.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/22/2016] [Accepted: 03/01/2016] [Indexed: 12/20/2022]
Abstract
Mutant cancer subpopulations have the potential to derail durable patient responses to molecularly targeted cancer therapeutics, yet the prevalence and size of such subpopulations are largely unexplored. We employed the sensitive and quantitative Allele-specific Competitive Blocker PCR approach to characterize mutant cancer subpopulations in ductal carcinomas (DCs), examining five specific hotspot point mutations (PIK3CA H1047R, KRAS G12D, KRAS G12V, HRAS G12D, and BRAF V600E). As an approach to aid interpretation of the DC results, the mutations were also quantified in normal breast tissue. Overall, the mutations were prevalent in normal breast and DCs, with 9/9 DCs having measureable levels of at least three of the five mutations. HRAS G12D was significantly increased in DCs as compared to normal breast. The most frequent point mutation reported in DC by DNA sequencing, PIK3CA H1047R, was detected in all normal breast tissue and DC samples and was present at remarkably high levels (mutant fractions of 1.1 × 10(-3) to 4.6 × 10(-2)) in 4/10 normal breast samples. In normal breast tissue samples, PIK3CA mutation levels were positively correlated with age. However, the PIK3CA H1047R mutant fraction distributions for normal breast tissues and DCs were similar. The results suggest PIK3CA H1047R mutant cells have a selective advantage in breast, contribute to breast cancer susceptibility, and drive tumor progression during breast carcinogenesis, even when present as only a subpopulation of tumor cells.
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Affiliation(s)
- Meagan B Myers
- US Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Rd., Jefferson, AR 72079
| | - Malathi Banda
- US Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Rd., Jefferson, AR 72079
| | - Karen L McKim
- US Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Rd., Jefferson, AR 72079
| | - Yiying Wang
- US Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Rd., Jefferson, AR 72079
| | - Michael J Powell
- DiaCarta, Inc., JOINN Innovation Park, 2600 Hilltop Drive, Richmond, CA 94806
| | - Barbara L Parsons
- US Food and Drug Administration, National Center for Toxicological Research, Division of Genetic and Molecular Toxicology, 3900 NCTR Rd., Jefferson, AR 72079.
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Myers MB, McKim KL, Meng F, Parsons BL. Low-frequency KRAS mutations are prevalent in lung adenocarcinomas. Per Med 2015; 12:83-98. [PMID: 27795727 PMCID: PMC5084916 DOI: 10.2217/pme.14.69] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIM This study quantified low-frequency KRAS mutations in normal lung and lung adenocarcinomas, to understand their potential significance in the development of acquired resistance to EGFR-targeted therapies. MATERIALS & METHODS Allele-specific Competitive Blocker-PCR was used to quantify KRAS codon 12 GAT (G12D) and GTT (G12V) mutation in 19 normal lung and 21 lung adenocarcinoma samples. RESULTS Lung adenocarcinomas had KRAS codon 12 GAT and GTT geometric mean mutant fractions of 1.94 × 10-4 and 1.16 × 10-3, respectively. For 76.2% of lung adenocarcinomas, the level of KRAS mutation was greater than the upper 95% confidence interval of that in normal lung. CONCLUSION KRAS mutant tumor subpopulations, not detectable by DNA sequencing, may drive resistance to EGFR blockade in lung adenocarcinoma patients.
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Affiliation(s)
- Meagan B Myers
- Division of Genetic & Molecular Toxicology, US FDA, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Karen L McKim
- Division of Genetic & Molecular Toxicology, US FDA, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Fanxue Meng
- Division of Genetic & Molecular Toxicology, US FDA, National Center for Toxicological Research, Jefferson, AR 72079, USA
| | - Barbara L Parsons
- Division of Genetic & Molecular Toxicology, US FDA, National Center for Toxicological Research, Jefferson, AR 72079, USA
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Lochhead P, Chan AT, Nishihara R, Fuchs CS, Beck AH, Giovannucci E, Ogino S. Etiologic field effect: reappraisal of the field effect concept in cancer predisposition and progression. Mod Pathol 2015; 28:14-29. [PMID: 24925058 PMCID: PMC4265316 DOI: 10.1038/modpathol.2014.81] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 02/12/2014] [Accepted: 04/02/2014] [Indexed: 02/07/2023]
Abstract
The term 'field effect' (also known as field defect, field cancerization, or field carcinogenesis) has been used to describe a field of cellular and molecular alteration, which predisposes to the development of neoplasms within that territory. We explore an expanded, integrative concept, 'etiologic field effect', which asserts that various etiologic factors (the exposome including dietary, lifestyle, environmental, microbial, hormonal, and genetic factors) and their interactions (the interactome) contribute to a tissue microenvironmental milieu that constitutes a 'field of susceptibility' to neoplasia initiation, evolution, and progression. Importantly, etiological fields predate the acquisition of molecular aberrations commonly considered to indicate presence of filed effect. Inspired by molecular pathological epidemiology (MPE) research, which examines the influence of etiologic factors on cellular and molecular alterations during disease course, an etiologically focused approach to field effect can: (1) broaden the horizons of our inquiry into cancer susceptibility and progression at molecular, cellular, and environmental levels, during all stages of tumor evolution; (2) embrace host-environment-tumor interactions (including gene-environment interactions) occurring in the tumor microenvironment; and, (3) help explain intriguing observations, such as shared molecular features between bilateral primary breast carcinomas, and between synchronous colorectal cancers, where similar molecular changes are absent from intervening normal colon. MPE research has identified a number of endogenous and environmental exposures which can influence not only molecular signatures in the genome, epigenome, transcriptome, proteome, metabolome and interactome, but also host immunity and tumor behavior. We anticipate that future technological advances will allow the development of in vivo biosensors capable of detecting and quantifying 'etiologic field effect' as abnormal network pathology patterns of cellular and microenvironmental responses to endogenous and exogenous exposures. Through an 'etiologic field effect' paradigm, and holistic systems pathology (systems biology) approaches to cancer biology, we can improve personalized prevention and treatment strategies for precision medicine.
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Affiliation(s)
- Paul Lochhead
- Gastrointestinal Research Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Andrew T Chan
- 1] Division of Gastroenterology, Massachusetts General Hospital, Boston, MA, USA [2] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Reiko Nishihara
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA [2] Department of Nutrition, Harvard School of Public Health, Boston, MA, USA
| | - Charles S Fuchs
- 1] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA [2] Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA
| | - Andrew H Beck
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Edward Giovannucci
- 1] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA [2] Department of Nutrition, Harvard School of Public Health, Boston, MA, USA [3] Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA
| | - Shuji Ogino
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA [2] Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA [3] Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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Lochhead P, Chan AT, Giovannucci E, Fuchs CS, Wu K, Nishihara R, O'Brien M, Ogino S. Progress and opportunities in molecular pathological epidemiology of colorectal premalignant lesions. Am J Gastroenterol 2014; 109:1205-14. [PMID: 24935274 PMCID: PMC4125459 DOI: 10.1038/ajg.2014.153] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 04/18/2014] [Indexed: 02/06/2023]
Abstract
Molecular pathological epidemiology (MPE) is an integrative molecular and population health science that addresses the molecular pathogenesis and heterogeneity of disease processes. The MPE of colonic and rectal premalignant lesions (including hyperplastic polyps, tubular adenomas, tubulovillous adenomas, villous adenomas, traditional serrated adenomas, sessile serrated adenomas/sessile serrated polyps, and hamartomatous polyps) can provide unique opportunities for examining the influence of diet, lifestyle, and environmental exposures on specific pathways of carcinogenesis. Colorectal neoplasia can provide a practical model by which both malignant epithelial tumor (carcinoma) and its precursor are subjected to molecular pathological analyses. KRAS, BRAF, and PIK3CA oncogene mutations, microsatellite instability, CpG island methylator phenotype, and LINE-1 methylation are commonly examined tumor biomarkers. Future opportunities include interrogation of comprehensive genomic, epigenomic, or panomic datasets, and the adoption of in vivo pathology techniques. Considering the colorectal continuum hypothesis and emerging roles of gut microbiota and host immunity in tumorigenesis, detailed information on tumor location is important. There are unique strengths and caveats, especially with regard to case ascertainment by colonoscopy. The MPE of colorectal premalignant lesions can identify etiologic exposures associated with neoplastic initiation and progression, help us better understand colorectal carcinogenesis, and facilitate personalized prevention, screening, and therapy.
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Affiliation(s)
- Paul Lochhead
- 1] Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK [2] The first two authors contributed equally to this work
| | - Andrew T Chan
- 1] Division of Gastroenterology, Massachusetts General Hospital, Boston, Massachusetts, USA [2] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA [3] The first two authors contributed equally to this work
| | - Edward Giovannucci
- 1] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA [2] Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA [3] Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Charles S Fuchs
- 1] Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA [2] Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA
| | - Kana Wu
- Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Reiko Nishihara
- 1] Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA [2] Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA
| | - Michael O'Brien
- Department of Pathology, Boston University Medical Center, Boston, Massachusetts, USA
| | - Shuji Ogino
- 1] Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, USA [2] Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, Massachusetts, USA [3] Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts, USA
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Ogino S, Lochhead P, Chan AT, Nishihara R, Cho E, Wolpin BM, Meyerhardt JA, Meissner A, Schernhammer ES, Fuchs CS, Giovannucci E. Molecular pathological epidemiology of epigenetics: emerging integrative science to analyze environment, host, and disease. Mod Pathol 2013; 26:465-84. [PMID: 23307060 PMCID: PMC3637979 DOI: 10.1038/modpathol.2012.214] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Epigenetics acts as an interface between environmental/exogenous factors, cellular responses, and pathological processes. Aberrant epigenetic signatures are a hallmark of complex multifactorial diseases (including neoplasms and malignancies such as leukemias, lymphomas, sarcomas, and breast, lung, prostate, liver, and colorectal cancers). Epigenetic signatures (DNA methylation, mRNA and microRNA expression, etc) may serve as biomarkers for risk stratification, early detection, and disease classification, as well as targets for therapy and chemoprevention. In particular, DNA methylation assays are widely applied to formalin-fixed, paraffin-embedded archival tissue specimens as clinical pathology tests. To better understand the interplay between etiological factors, cellular molecular characteristics, and disease evolution, the field of 'molecular pathological epidemiology (MPE)' has emerged as an interdisciplinary integration of 'molecular pathology' and 'epidemiology'. In contrast to traditional epidemiological research including genome-wide association studies (GWAS), MPE is founded on the unique disease principle, that is, each disease process results from unique profiles of exposomes, epigenomes, transcriptomes, proteomes, metabolomes, microbiomes, and interactomes in relation to the macroenvironment and tissue microenvironment. MPE may represent a logical evolution of GWAS, termed 'GWAS-MPE approach'. Although epigenome-wide association study attracts increasing attention, currently, it has a fundamental problem in that each cell within one individual has a unique, time-varying epigenome. Having a similar conceptual framework to systems biology, the holistic MPE approach enables us to link potential etiological factors to specific molecular pathology, and gain novel pathogenic insights on causality. The widespread application of epigenome (eg, methylome) analyses will enhance our understanding of disease heterogeneity, epigenotypes (CpG island methylator phenotype, LINE-1 (long interspersed nucleotide element-1; also called long interspersed nuclear element-1; long interspersed element-1; L1) hypomethylation, etc), and host-disease interactions. In this article, we illustrate increasing contribution of modern pathology to broader public health sciences, which attests pivotal roles of pathologists in the new integrated MPE science towards our ultimate goal of personalized medicine and prevention.
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Affiliation(s)
- Shuji Ogino
- Department of Pathology, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02215, USA.
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Parsons BL, Myers MB. KRAS mutant tumor subpopulations can subvert durable responses to personalized cancer treatments. Per Med 2013; 10:191-199. [PMID: 27867401 DOI: 10.2217/pme.13.1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
KRAS mutations in colorectal and lung cancers predict failure to respond to therapies that target the EGFR. Significant percentages of patients with KRAS wild-type tumors also fail to respond to these therapies. Relapse occurs in patients with KRAS wild-type and mutant tumors, with moderately longer progression-free survival in patients with KRAS wild-type tumors. Colon and lung tumors frequently carry KRAS mutant tumor subpopulations not detected by DNA sequencing. This suggests detected and undetected KRAS mutant subpopulations in colon and lung tumors are undermining the efficacy of anti-EGFR therapies. Therefore, consideration should be given to combining therapies that target KRAS mutant cells with those that downregulate EGFR signaling. As tumors are frequently polyclonal in origin and comprised of distinct clonal populations carrying complementing genetic and/or epigenetic lesions, preclinical models that assess the efficacy of combination therapies in the context of heterogeneous tumor cell populations will be essential for progress in this area.
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Affiliation(s)
- Barbara L Parsons
- US FDA, National Center for Toxicological Research, Division of Genetic & Molecular Toxicology, HFT-120, 3900 NCTR Road, Jefferson, AR 72079, USA
| | - Meagan B Myers
- US FDA, National Center for Toxicological Research, Division of Genetic & Molecular Toxicology, HFT-120, 3900 NCTR Road, Jefferson, AR 72079, USA
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Myers MB, McKim KL, Parsons BL. A subset of papillary thyroid carcinomas contain KRAS mutant subpopulations at levels above normal thyroid. Mol Carcinog 2012; 53:159-67. [PMID: 22930660 DOI: 10.1002/mc.21953] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Revised: 07/27/2012] [Accepted: 08/01/2012] [Indexed: 01/07/2023]
Abstract
The molecular pathogenesis of papillary thyroid carcinoma (PTC) is largely attributed to chromosomal rearrangements and point mutations in genes within the MAPK pathway (i.e., BRAF and RAS). Despite KRAS being the 6th most frequently mutated gene for all cancers, the reported frequency in thyroid cancer is only 2%. This may be due, in part, to the use of insensitive mutation detection methods such as DNA sequencing. Therefore, using the sensitive and quantitative ACB-PCR approach, we quantified KRAS codon 12 GGT → GAT and GGT → GTT mutant fraction (MF) in 20 normal thyroid tissues, 17 primary PTC, 2 metastatic PTC, and 1 anaplastic thyroid carcinoma. We observed measurable levels of KRAS codon 12 GAT or GTT mutation in all normal thyroid tissues. For PTCs, 29.4% and 35.3% had KRAS codon 12 GAT and GTT MF above the 95% upper confidence interval for the corresponding MFs in normal thyroid. The highest observed KRAS codon 12 GTT MFs were associated with tumors with follicular characteristics and relatively high levels of tumor necrosis. The results indicate KRAS mutant subpopulations are present in a large number of thyroid tumors, a fact previously unrecognized. The presence of KRAS mutation may indicate a tumor with an aggressive phenotype, thus directing the course of clinical treatment.
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Affiliation(s)
- Meagan B Myers
- Division of Genetic and Molecular Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas
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