Biomarkers in Anatomic PathologyAdding Value in Diagnostics
Jennifer Hunt, MD, MEd, FCAP
Biomarkers in Anatomic Pathology:Adding Value in Diagnostics
Jennifer L. Hunt, M.D., M.Ed. Section Head, Surgical PathologyDirector, Head and Neck and Endocrine PathologyDirector, Molecular Anatomic Pathology Unit
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“The microscope is not, for the biologist or physician, an instrument which he can indifferently make use of; its employment is absolutely necessary. Accustomed to judge from exterior characters alone, pathologists should not be astonished that many results obtained by them are shown to be inexact or incomplete by the microscope. Far from believing that the fault comes from the new information added by the microscope, it is the history of diseases which must be taken up again and revised, starting from the new and much more precise notions of the tissue furnished by microscopy.”
Auguste Nélaton (1807 – 1873)
1600 1700 1800 1900
Zaccharias Janssen (1590-1608): First Microscope
Anton van Leeuwenhoek (1632-1723): Bacteria
Rudolph Virchow (1821-1902): Father of Microscopic Pathology
Carl Rokitansky (1804-1878): Father of Autopsy Pathology
Robert Hooke (1635-1703) Father of Microscopy
1950 1960 1970 1980 1990 2000
Kary Mullis (1983): Polymerase Chain Reaction (Nobel Prize, 1993)
Watson & Crick (1953): DNA (Nobel Prize, 1962)
Alfred Knudson (1971): Tumor suppressor genes (Lasker Award, 1998)
Sternberger (1978): Immuno-cytochemistry
Ernst Ruska & Max Knott (1931): Electron Microscope (Nobel Prize, 1986)
Peyton Rous (1910): Oncogenes (Nobel Prize 1966)
Frederick Sanger (1975): Sequencing (Nobel Prize, 1980)
Gross Exam (1500-1800)
Microscopic Analysis (1800-1930)
Electron Microscopy (1930-1980)
IHC (1980-2000)
DNA (2000)
MicroRNA
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1800DiagnosticAssay Era
Agenda: Biomarkers in AP
•The Past: Diagnosis
•The Present: Prognosis
•The Future: Therapeutics
1960PrognosticAssay Era
2000TherapeuticAssay Era
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Biomarkers: Definition
• “A specific physical trait or measurable biologically produced change in the body connected with a disease or health condition”
•Any marker of biological status
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Biomarkers: Examples
Biomarker Assay What it detects
Hemoccult Digital exam Occult blood
Dukes Stage Histology Risk stratification
Serum CEA Blood test Recurrent disease
Microsatellite instability
PCR Hereditary cases
KRAS Sequencing Therapeutic response
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Drivers of Biomarker Testing
•Understanding pathogenesis
•Better diagnosis
•Better prognostic information
•Better understanding of therapeutic response
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Biomarkers in Pathology
•The Past: Diagnosis
•The Recent Past: Simple Prognosis
•The Present–Advanced Prognosis
–Understanding Biology
•The Future: Therapeutics
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Colon Cancer Diagnostics
•1700’s: Gross diagnosis
•1800’s: Microscopic diagnosis
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1. Abdominal mass with cachexia and bowel symptoms
2. Abdominal mass and histologic identification of tumor
3. Gradual bowel symptoms, cachexia, stricture symptoms, and histologic identification of tumor
Einhorn M, 1900
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Gross Exam (1500-1800)
Microscopic Analysis (1800-1930)
Electron Microscopy (1930-1980)
IHC (1980-2000)
DNA (2000)
MicroRNA
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Biomarkers in Pathology
•The Past: Diagnosis
•The Recent Past: Simple Prognosis
•The Present–Advanced Prognosis
–Understanding Biology
•The Future: Therapeutics
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Colon Cancer Anatomic Prognosis
•1932: Dukes Staging System (rectal)
•1953: Astler-Coller modification of Dukes
•1965: AJCC Staging System
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Colon Cancer Biology & Prognosis
•1990-1993: Genetics of familial adenomatous polyposis (FAP)–1991: APC locus identified
–1993: APC gene cloned
•1993: Genetics of hereditary non-polyposis colorectal carcinoma (HNPCC)–Microsatellite instability identified
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Genetic of Colon Cancer
15%
Tumor SuppressorGene (85%)
HNPCC5%
Microsatellite unstable cases (15%)
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Genetics of Colon Cancer
Tumor suppressor gene (APC)
DNA mismatch: hereditary
DNA mismatch: sporadic
Microsatellite instability
Negative Positive Positive
Immuno-stains
N/A hMSH2 (-) hMLH1 (-)
BRAF mutation
N/A Wild-type Mutant (40%)
hMLH1 methylation
N/A Negative Positive
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Gross Exam (1500-1800)
Microscopic Analysis (1800-1930)
Electron Microscopy (1930-1980)
IHC (1980-2000)
DNA (2000)
MicroRNA
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Biomarkers in Pathology
•The Past: Diagnosis
•The Recent Past: Simple Prognosis
•The Present–Advanced Prognosis
–Understanding Biology
•The Future: Therapeutics
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Approved Targeted Therapies
Drug Target of drug
Trade name
Tumor
Gefitinib Erlotinib Cetuximab Panitumumab
EGFR Iressa Tarceva Erbitux Vectibix
Lung Colon
Trastuzimab Her2/neu Herceptin Breast
Bevacizumab VEGF Avastin Colon
Imatinib mesylate
Tyrosine kinase
Gleevec GIST, CML
Bortezomib Proteasome Velcade Multiple myeloma, Mantle cell lymphoma
Rituximab CD20 Rituxan B cell lymphoma
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Success of Targeted Therapy
Response CostSide Effects
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Cost Per Month
•Gleevec: $3,000
•Herceptin: $2,800
•Rituxan: $12,000
• Iressa: $1,800
•Tarceva: $2,700
•Erbitux: $9,600
•Vectibix: $8,000
75% of personal bankruptcy is caused by a catastrophic illness
Himmelstein DU. 24(1),2005
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Future: Biomarkers for Therapeutics
•Selection for therapeutics–Companion diagnostics
•Monitoring of therapeutic response–Minimal residual disease testing
•Predicting resistance to therapeutics–Markers of tumor resistance
TRANSMEMBRANECELL
MEMBRANE
ANGIOGENESISPROLIFERATION APOPTOSIS
Extracellular Domain
Cytoplasmic Domain
Transmembrane Domain
EGFRCourtesy of Dr. S. Dacic
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Epidermal Growth Factor Receptor
•Altered in many tumors–Protein Expression
–Gene copy number
–Gene sequence
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Epidermal Growth Factor Receptor
•Blockade of EGFR pathway –Monoclonal antibody
–Small molecule inhibitors of tyrosine kinase
Monoclonal Ab(Erbitux)
Small moleculeinhibitors
(Iressa, Tarceva)
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Colon Cancer Therapeutics
•2004: EGFR Pathway in colon cancer–Erbitux approved by FDA for colon cancer treatment
–EGFR antibody approved by FDA
•2008: Predictors of resistance–KRAS mutations insensitivity to Erbitux
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October, 2007
Completion of CA225006
Erbitux Timeline
March, 2009
Anticipated Completion
of CA225014
Early 2005
Literature againstEGFR IHC testing
February, 2004
FDA Approval• Erbitux• EGFR PharmDx
December, 2001
FDA negative report
June, 2008
ASCO data: KRAS
Mutation
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Challenges for Pathology
•Biomarker selection
•Testing–Assay development
–Validation
– Interpretation
•Operational impediments–Patents
–Cost and reimbursement
Pathologist Training
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Who Validates New Assays?
•Laboratory technical staff
•Anatomic pathologists
•Molecular pathologists
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Predicted Labor Shortage by 2020
150,000
340,000
85,000 72,000
0
50,000
100,000
150,000
200,000
250,000
300,000
350,000
2020 shortage
Pharmacists
Nurses
Physicians
Med Techs
Nu
mb
er o
f p
eop
le
Estimated Labor Shortage by 2020 Auerbach, D. Health Affairs. 26(1), 2007:178AAMC Study on Physician Shortage, August 2007Castleberry BM, Lab Med 30, 1999: 174
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Molecular Genetic Pathology Fellowships
Source http://www.acgme.org/adspublic/Accessed March 22, 2008
Ab
solu
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um
ber
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Who Signs Out Results?
•Send-out laboratories
•Anatomic pathologists
•Molecular pathologists
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AMP Test Directory
•Microsatellite instability: 11 laboratories
•EGFR: 5 laboratories
•K-RAS: 4 laboratories
http://www.amptestdirectory.org/Accessed 6/2/2008
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Training of Pathologists
Data courtesy of CAPJune, 2008
PCR (1983)
IHC (1978)
Sequencing (1975)
Hybrid capture for HPV (1995)
Quantitative PCR (1992)
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Number of MGP Applicants
0
10
20
30
40
50
60
70
2002 2003 2005 2007
# Examinees
# Passed
Source: https://www.abpath.orgAccessed 3/23/2008
End of Grand-fatherPeriod
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Challenges for Pathology
•Biomarker selection
•Testing–Assay development
–Validation
– Interpretation
•Operational impediments–Patents
–Cost and reimbursement
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Gross Analysis
Microscopic Analysis
Electron Microscopy
Immunohisto-chemistry
DNA
MicroRNA
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“The microscope is not, for the biologist or physician, an instrument which he can indifferently make use of; its employment is absolutely necessary. Accustomed to judge from exterior characters alone, pathologists should not be astonished that many results obtained by them are shown to be inexact or incomplete by the microscope. Far from believing that the fault comes from the new information added by the microscope, it is the history of diseases which must be taken up again and revised, starting from the new and much more precise notions of the tissue furnished by microscopy.”
Auguste Nelaton (1807 – 1873)(Modified for 2008)
“Biomarker testing
biomarkers.
the microscopic appearance,
(s)he
biomarkers,
biomarkers.”
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