Genetics and Genomics in Cancer 2013: How Genomics is Changing Cancer Care, Dr. Lea Velsher
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Transcript of Genetics and Genomics in Cancer 2013: How Genomics is Changing Cancer Care, Dr. Lea Velsher
Genomics and Cancer 2013
How Genomics is Changing Cancer Care
Faculty/Presenter Disclosure
Faculty: Dr. Lea Velsher
Advisor for Thunder Bay Genetics, NRGP
Physician at North York General Hospital, Genetics
Consultant in Genetics for Medcan Clinic
No conflicts of interest to declare
Learning
• Explain how the genetics of sporadic and hereditary cancers differ
• Review features that suggest an inherited cancer risk
• Discuss how genomics is being integrated into cancer diagnosis and treatment
• Somatic Cells • Germ Cells
Epigenomics
• Method for turning genes ‘off’ or ‘on’
• Reversible changes to chromosomes
• No mutations in the DNA code itself
• Environment may alter epigenomics in cells
5
Epigenomics: regulating expression of genes
Cancer is a genetic disease: accumulation of mutations and
epigenomic changes in somatic cells
7
What patterns make us think of a hereditary risk?
• Family history
• Personal history
• Pathology
• Unusual features
Family History
• 3 or more close relatives with cancer
• Cancer < 50 years old
• Clusters of certain cancer types
• Person has >1 primary cancer
52 y.o. woman Ductal Breast Cancer
3 2
Breast 75Breast 60
Breast 38
Personal history
Colon cancer 29 years old
Pathology of the tumour
• Medullary Breast Cancer:– Triple negative in premenopausal woman– Consider BRCA1 testing
• Right sided mucinous undifferentiated colon cancer– Consider doing Immunohistochemistry for
Lynch (HNPCC)
• Medullary thyroid cancer– Consider genetic testing for MEN2
Unusual findings
Multiple polyps on colonoscopy
• A benign neoplasm of sebaceous tissue, with a predominance of mature secretory sebaceous cells.
Sebaceous Adenoma
Most cancer is sporadic
We can use the genomic changes unique to the cancer for:•Prognosis •Therapy•Screening
Genomic analysis of the tumour cells
19
For ER +, Node - tumours
Screening for cancer using cancer biomarkers
Genetic biomarkers as a screen
• Methylated Septin 9
test
– Blood test
– Looks at a gene that is
methylated in colon
cancer
– Sensitivity and specificity
maybe 60 - 85%
Targeted Therapy
Altered genome leads to altered protein products
Target the cancer cells based on their altered genotype and phenotype
Pharmacogenomics
• Germ line polymorphisms
• Alter pharmacokinetics/dynamics of
chemotherapy agents
• UGT1A1 – homozygous SNP reduces
activity
– Increases toxicity of Irinotecan
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E.G. CYP2D6 and Tamoxifen
What will the future hold?
• Cheaper, simpler, faster testing
• Incorporation of genomic markers into risk algorithms
• Targeted ‘personalized’ treatment based on genomic information
• Pharmacogenomic testing at point of care
Summary Points
• All cancer is ‘genetic’ but only a small number of cases are ‘hereditary’
• Genomic and epigenomic changes within the cancer (somatic mutations) can be used in screening and treatment
• A person’s genomic (germ line variations) make up may influence treatment
Thank You