Cancer Genetics Flashcards
1
A
- MSH2, MLH1, PMS2, MSH6, EPCAM (mismatch repair genes, responsible for 38%, 32%, 15%, and 14%, and 1-3% of LS cases respectively)
- Increased risk for (%):
- Endometrial cancer: 28-60
- CRC: 30-80 (M at higher risk)
- Gastric: 5-13
- Ovarian: 4-38
- Small bowel: 3-6
- Upper urinary tract: 8.4
- CNS: 4
- Biliary tract: 2-18
- Breast: 0-13
- Sebaceous gland neoplasms: 1-9
2
Q
IHC
A
immunohistochemistry (tumor analysis) of the MMR proteins
3
Q
MSI
A
- Microsatellite instability analysis (tumor analysis)
- Found in 15% of CRCs
- MSI-H (high MSI) may indicate Lynch syndrome
4
Q
hereditary vs. familial vs. sporadic
A
- hereditary 5-10%
- familial 15-25% (due to shared env. or unknown genetic variants)
- sporadic 65-80%
5
Q
Gen pop baseline lifetime risks
A
- CRC: 5-6%
- Uterine: 2-3%
- Breast and prostate: ~12%
- Ovarian: 1%
- Panc: 1.5%
- Bladder: 2.5%
- Gastric, small bowel, urothelial, CNS: <1%
6
Q
risk calculation models - HBOC
A
- BRCAPro (lifetime risk)
- Tyler-Cuzick (lifetime risk)
- BODICEA (lifetime risk)
- Gail (5 yr risk)
- Claus (5 yr risk?)
7
Q
risk calculation models - Lynch syndrome
A
- MMRpredict
- Leiden
- MMRPro
- PREMM
8
Q
BRAF and MLH1 hypermethylation testing
A
- hypermethylation of MLH1 and somatic mutations of BRAF
- Indicate a sporadic, NON-LS CRC/endo cancer
9
Q
Familial adenomatous polyposis
A
- APC; AD
- Genetic testing criteria: >10 polyps in lifetime?
- Increased cancer risks (%):
- CRC:
10
Q
Li-Fraumeni syndrome
A
- TP53 (“guardian of the genome”); AD
- Predisposition to all cancers (90% lifetime risk), esp. breast cancer
- Remember the B’s: Bone, Brain, Blood, Breast! (%):
- Breast: 28
- Soft tissue: 14
- Brain: 13
- Adrenal gland: 11
- Bone: 8
- Must do skin punch biopsy for confirmatory testing.
- Mgmt:
- Exams every 6-12 months >20yr old
- 20-29 annual breast MRI, discuss RRM
- 30-75: annual breast MRI, consider tomosynthesis and RRM
- Colonoscopy every 2-5 yrs >25yrs old
- Annual derm exam
- Annual whole body and brain MRI
11
Q
chronic myelogenous leukemia
A
- somatic, not inherited
- Caused by Philadephia chromosomes (fusion of chr9 and chr22, specifically BCR-ABL1)
12
Q
Fanconi anemia
A
- BRCA2; AR
- Also associated with other genes (E.g., FANC genes, PALB2, RAD51C, BRIP1, SLX4)
- Age of onset 6-8yrs
- Bone marrow failure, organ defects, CALMs, short stature
- Increased cancer risk:
- 10-30% risk for AML (acute myeloid leukemia) or tumors (head, neck, skin, GI, GU)
13
Q
PALB2
A
- PALB2; AD
- Increased cancer risks (%):
- F breast cancer risk: 33-58?/84?
- Increased M br. cancer, panc, ovarian, prostate
- Mgmt:
- Annual mammo, consideration of tamoxifen and MRI >30yo
- RRM- NO, unless fam hx is risky
- Counsel about Fanconi risk if both parents are carriers
14
Q
Hereditary diffuse gastric cancer syndrome
A
- CDH1; AD
- Diffuse gastric cancer: 56-83%
- F breast cancer risk: 39-52% (lobular only)
- Mgmt:
- Gastrectomy between age 18 and 41
- Can consider UGI with biopsies every 6-12 months
- >30yo: annual mammo/MRI with consideration of tamoxifen
15
Q
Peutz-Jeghers Syndrome
A
- STK11; AD
- Hamartomas, derm signs (freckling in childhood), GI pain/anemia from GI bleeding
- Risks (%):
- Lifetime risk of all cancers: 93%
- CRC: 40
- Breast: 30-50
- Panc: 11-36
- Stomach: 29
- Small bowel: 13
- Lung cancer
- Gyn cancers
- Ovarian: 20 (often sex-cord tumors with annular tubules)
- Cervical cancer: 10
- Uterine: <10
- Mgmt:
- Mammo and breast MRI 6 months >25yo
- Colonoscopy and UGI every 2-3y in late teens
- Small bowel visualization
- Many more….
16
Q
ATM
A
- ATM; AD
- Increased risk for cancer:
- Risk or F br. cancer: 2-4x
- Ovarian+
- Mgmt:
- Annual mammo >40yo, consider tomosynth and breast MRI
- No RRM
-
Ataxia telangiectasia risk if other parent is carrier
- Increased risk for lymphoma and leukemia, and breast cancer
- Telangiectasias, progressive loss of ability to walk and talk, choreoathetosis, hypersensitive to ionizing rad.
17
Q
CHEK2
A
- CHEK2; AD
- F breast cancer: 2x risk
- Increased colon risk
- Mgmt:
- Annual mammo and colonoscopy >40yr, consider tamoxifen/breast MRI
- No RRM
- Low penetrance mutation Ile157Thr
18
Q
Neurofibromatosis 1
A
- NF1; AD
- F breast cancer risk: 3-5x
- Increased risk for:
- Brain tumors
- Leukemia
- GIST (gastrointestinal stromal)
- Parangangliomas and pheochromocytomas
- Mgmt:
- Annual mammo and breast MRI >30yr, consider tamoxifen and breast MRI
- No RRM
- Refer to NF1 specialist for further eval for CALMs, Lisch nodules, inguinal freckling, neurofibromas, skeletal dysplasia, LD
19
Q
BARD1 and MRE11A
A
- AD
- Increased risk for breast and ovarian cancer
- No mgmt recommendations currently
20
Q
BRIP1, RAD51C/D and RAD50
A
- AD
- Increased risk for F breast cancer, ovarian (9% for BRIP1)
- Consider RRSO at 45-50yo
- Counsel about Fanconi anemia risk