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Part Two

Part Two. Welcome back. Familial Cancer Genetics. Cancer Genetics. 5-10% of all cancer clearly linked to an inherited gene alteration If cancer seen at younger ages (before 50) possible that inherited genes increased susceptibility

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Part Two

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  1. Part Two Welcome back

  2. Familial Cancer Genetics

  3. Cancer Genetics • 5-10% of all cancer clearly linked to an inherited gene alteration • If cancer seen at younger ages (before 50) possible that inherited genes increased susceptibility • Some genetic conditions increase someone’s risk of getting several different types of cancer at young age (eg. Li-Fraumeni syndrome, MEN 1) • Some gene alterations lead to uncontrolled cell growth: • tumour suppressor genes • oncogenes • DNA repair genes

  4. Breast Cancer • BRCA 1 & BRCA 2 testing may be available for people at high risk, but others genes known to be involved • If gene alteration found, woman at up to 80% lifetime risk of developing breast cancer • Carry risk of other cancers; ovary (BRCA 1 = 44%, BRCA 2 = 27%), and a slightly increased risk prostate, pancreas and some other cancers • Dominantly inherited through families (ie. only one copy of the altered gene needed for it to have effect)

  5. AUTOSOMAL DOMINANT INHERITANCE Parents Gametes At conception Unaffected Affected

  6. Hereditarygene alteration 1 Somatic mutation Somatic mutation Cancer Normal Tissue

  7. Hereditarygene alteration Somatic mutation 2 Somatic mutations Cancer Cancer

  8. What would indicate that a woman is at higher risk of developing breast/ovarian cancer? Relative with breast cancer before the age of 40 Relative with bilateral breast cancer Relative with male breast cancer 2+ relatives on the same side of the family affected by breast cancer (especially if affected at younger ages) 2+ relatives with ovarian cancer

  9. Breast Cancer Referral

  10. Low risk – manage in primary care • Older age of onset • Different sides of the family Case 1 Breast cancer 65 70 76 46 Kay 49 51 53 55 Reassure and explain population risk. Advise on symptom awareness and to report any changes in family history

  11. Ovarian Cancer

  12. Refer – high risk • Young age onset • Equal transmission through men • Multiple tumours in one individual • Breast and ovarian cancer Case 2 42 48 breast cancer 56 ovarian cancer Breast cancer Ovarian cancer 32 Janet

  13. Colorectal Cancer Familial Adenomatous Polyposis (FAP) Hereditary Non-Polyposis Colorectal Cancer (HNPCC). Other cancers associated with HNPCC – endometrial, stomach, ovarian Supporting Genetics Education for Health www.geneticseducation.nhs.uk

  14. Bowel Cancer HNPCC related cancers include endometrial, gastric, ovarian, pancreatic and urothelial

  15. Case 3 35 died in war 68 73 60’s 77 78 73 75 43 Colorectal cancer 32 Peter Refer – moderate risk Young age of onset (under 45)

  16. Case 4 Colorectal cancer Endometrial cancer 55 69 49 42 George 80 75 48 78 Refer – High risk Young age of onset, Endometrial and Bowel Two generations, Polyps 39 Polyps 30 Martin 42

  17. Referral for family history of cancer • Young age at onset, • Pattern of similar tumours on one side of the family (or multiple primaries in one individual) • Use national/local guidelines e.g. NICE familial breast cancer • Remember ethnicity e.g. – Chinese, Indian, Ashkenazi Jewish ancestry • If in doubt - Contact the Clinical Genetic Service

  18. Patient Information • Detailed information of affected family members required • Patient will receive information regarding level of risk and options • Will not necessarily mean a genetic test

  19. AUTOSOMAL DOMINANT INHERITANCE Parents Gametes At conception Unaffected Affected

  20. Familial Hypercholesterolaemia • If fulfil Simon Broome criteria, refer to specialist lipidologist • Where Genetic testing is not available, cascade testing for family members by fasting lipid profile • Children tested below 10 years • Boys have lower cholesterol during puberty

  21. Heart UK Definition using Simon Broome Register Definite Familial Hypercholesterolaemia: PLUS b) Tendon xanthomas in patient, or in 1st degree relative (parent, sibling, child), or in 2nd degree relative (grandparent, uncle, aunt) OR c) DNA-based evidence of an LDL receptor mutation or familial defective apo B-100

  22. Heart UK Definition using Simon Broome Register Possible Familial Hypercholesterolaemia: PLUS • d) Family history of myocardial infarction: below age of 50 in 2nd degree relative or below age 60 in 1st degree relative Or • e) Family history of raised cholesterols: • >7.5 mmol/l in adult 1st or 2nd degree relative or • > 6.7 mmol/l in child or sibling under 16

  23. X-LINKED INHERITANCE WHERE THE MOTHER IS A CARRIER Father Mother Parents (Unaffected) (Carrier) Gametes X Y X X At conception Son Daughter Daughter Son (Affected) (Carrier)

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