The document summarizes information about hereditary breast and ovarian cancer syndrome (HBOC). It finds that 10-25% of breast cancer and 5-10% of ovarian cancer is considered hereditary. The majority of HBOC cases, around 84%, are caused by mutations in the BRCA1 and BRCA2 genes. Carriers of BRCA1 and BRCA2 mutations have significantly increased lifetime risks of developing breast cancer (56-87% for both genes) and ovarian cancer (44% for BRCA1, 27% for BRCA2) compared to the general population. Genetic testing for BRCA1 and BRCA2 mutations is available to assess cancer risk and guide risk-reducing medical or

1. How Much Breast & Ovarian Cancer Is Hereditary?
Ovarian CancerBreast Cancer
10-25%
70-80%
5–10% 15-20%
Sporadic
Familial
Hereditary

2. Features of Hereditary and Sporadic Cancer in Hereditary
Breast and Ovarian Cancer Syndrome (HBOC)
Hereditary Sporadic
• Multiple affected blood relatives in more
than one generation
• Typically, earlier age of onset (<50)
• Individuals with bilateral or more than
one cancer diagnosis (breast/ovarian)
•Males with breast cancer
• One or only a few affected blood
relatives
• Typically, later age of onset
Br, 42
Br, 47
Ov, 58
Br, 35Ov, 50
Br, 72

3. Chromosomes
BRCA1BRCA2
***~84% of HBOC is caused by BRCA1 & BRCA2

4. 50% 50%
BRCA1
-chromosome 17
BRCA2 -
chromosome 13

5. BRCA1 & BRCA2
Lifetime Cancer Risks
Type
of Cancer
General
Population
BRCA1 BRCA2
Female Breast
Cancer
12% 56-87% 56-87%
2nd
Breast Cancer 0.8-1.5%
(per year – 5y)
5 year: 20%
Lifetime: 64%
5 year: 12%
Lifetime: 50%
Ovarian Cancer 1.8% 44% 27%
Male Breast
Cancer
0.1% ~1-2% 6-10%
Pancreatic Cancer <1% - - ~1.5-5%
Melanoma 1-2% - - Increased
Prostate Cancer 12% ~15-20% ~15-20%

6. Cancer Screening and Risk-Reduction Options
Increased Screening Risk-Reduction
Surgery
Medications
Breast
• Monthly breast-self
exam
• Clinical breast exam
every 6 months
• Yearly mammogram
• Yearly MRI
Bilateral Mastectomy
can reduce the risk of
breast cancer by 96%
Tamoxifen/
Raloxifene can
reduce the risk of
breast cancer by
approximately 50%
Ovarian
• Transvaginal
Ultrasound
• CA-125 blood tests
every 6 months
* Limitations: Screening
is not effective at picking
up early stage cancer *
Bilateral Salpingo-
Oophorectomy
(removing both the
ovaries and fallopian
tubes) can reduce the
risk of ovarian cancer
by 96%
Oral Contraceptives
(birth control pills)
can reduce the risk
of ovarian cancer by
approximately 50%

7. Genetic Testing for Breast Cancer
BRCA1
BRCA2
ATGCCGTATAGCTAGTCGATGTACG
• Blood Test
• Misspellings, Deleted, or Added DNA [i.e., mutation]
• Tests offered:
-Analysis of BRCA1 & BRCA2 genes [3-4 weeks]
-Breast/Ovarian Panels [12 weeks]
-Targeted mutation analysis (when family mutation is known) [3 weeks]

8. Possible Test Results
Positive Result Increased chance of certain cancers;
(implications for other family
members ) (Known mutation detected)
Mutation has been identified in
Negative Result family (True Negative)
(No mutation detected) - No increase in risk above the
general population
Mutation has not been identified in
family and patient has cancer
- Cancer most likely not due to
BRCA1/2
Mutation has not been identified
in family and patient does not have
cancer
- Doesn’t rule out BRCA1/2
Variant of Uncertain Significance Cancer risk not yet known
(Mutation, but implications/management are not known)

9. Implications for
other family
members

10. Breast/Ovarian Panels
**Includes BRCA1/2 & 19 additional genes that can increase the risk for breast cancer
**High risk gene panel-BRCA1/2, CDH1, PTEN, STK11, TP53