Family History
Does a family history of breast cancer affect my risk of developing breast cancer?
Is ovarian cancer related to breast cancer?
Is prostate cancer related to breast cancer?
Is lung cancer related to breast cancer?
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Family History

Does a family history of breast cancer affect my risk of developing breast cancer?

A woman with a first degree relative (mother, sister, daughter) with breast cancer is at a higher risk for developing breast cancer. It is estimated that a woman with one first degree relative with cancer has a 1.5-2.0 relative risk of developing breast cancer compared to a woman whose family is free of breast cancer (a relative risk greater than 1 shows an increased incidence for that population). Having 2 first degree relatives diagnosed with cancer increases the relative risk to 55. If the first degree relative was diagnosed premenopausally with bilateral breast cancer (cancer in both breasts) the relative risk for first degree relatives is 20. While the relative risk is 10 for those whose first degree relatives were diagnosed after menopause.
 The fact that breast cancer happens to appear in the family does not mean that there’s a genetic predisposition. Here, the incidence could be due to other factors such as diet, hormones, or exposure to carcinogens. But 5-10% of breast cancers are genetic due to inherited mutations (change in DNA sequence) in breast cancer susceptibility genes BRCA1 and BRCA2. Mutations in these genes account for 80% of inherited breast cancer. But these mutations appear in less than 1% of the population and there are molecular tests available to detect them. It is important to remember that not all women that carry BRCA1 and BRCA2 mutations have a family history of breast cancer and not all family histories are due to mutations in these genes. Therefore, as mentioned above, other factors might be involved.

Is ovarian cancer related to breast cancer?

 Breast cancer and ovarian cancer have been linked due to mutations in BRCA1 and BRCA2. Women who carry mutations in these genes have a higher risk of developing breast and ovarian cancer. Studies have shown that an inherited mutation in BRCA1 and BRCA2 can increase the risk of developing breast cancer by 85% and ovarian cancer by 50%. Therefore, a family that has a history of both breast and ovarian cancer could have a mutation in either one of the genes. For women who know that they carry a mutation, it is recommended that they get an annual mammogram, a breast clinical examination every 6 months, and do breast self exams monthly. For those who have a family history of ovarian cancer, breast cancer, or both but don't know if they’re carriers, it is recommended that they get annual mammograms, annual clinical breast exams, and do monthly self exams. All should start this practice in their twenties for early detection.

Is prostate cancer related to breast cancer?

 Mutations in BRCA1 and BRCA2 have also been associated with prostate cancer. Hence, a family history of prostate cancer could also predispose to breast cancer. It was found that families with multiple cases of prostate cancer had an increased risk for developing breast cancer (relative risk=2.3) than those with a single incidence of prostate cancer. The risk is even higher if the family had an early onset of prostate cancer (relative risk=5.5).

Is lung cancer related to breast cancer?

 No genes have been identified yet that link lung cancer and breast cancer. But there is some evidence that suggest that a family history of lung cancer may affect the incidence of breast cancer in first degree relatives. Although not many studies have been done, a study found that a positive family history of early onset of lung cancer increases the risk for developing breast cancer in first degree relatives 5.1-fold. Relatives of cases with adenocarcinoma of the lung were at higher risk (relative risk=6.3). Therefore, shared susceptibility genes may act to increase early onset of lung and breast cancer in families.

Support Groups

Cancer Information Service (NCI)
Toll Free: 1-800-4cancer   (1-800-422-6237)
TTY: 1-800-332-8615

National Cancer Institute (NCI)
Office of Cancer Communications
Building 31, Room 10A24
Bethesda, MD 20892
(Offers accurate, up to date information on cancer to cancer patients, family, physicians, and the general public. Respond in english, spanish, and on TTY equipment)

(Information on cancer treatment, prevention, genetics, support groups, clinical trials, and a bibliography database)

Cancer Trials
(Information on clinical trials, research news, and other sources)

American Cancer Society
National Headquarters
1599 Clifton Road, N.E.
Atlanta, GA 30329-4251
1-800-ACS- 2345

National Alliance of Breast Cancer Organizations (NABCO)
9 East 37th Street, 10th Floor
New York, NY 10016
(212) 719-0154
(Helps cancer patients make informed decisions about treatment)

Y-Me National Headquarters
212 W. Van Buren St.
Chicago, IL 60607-3908
1-800-221-2141 (9-5, M-F)
312-986-8228 (24 hrs)
(Hotline counseling, educational programs, and self help meetings)

Wellness Community
10921 Reed Hartman Highway, Suite 215
Cincinnati, OH 45242
Toll Free: 1-888-793-WELL
(Free psychological and emotional support for cancer patients and family)

Cancer Care, Inc
275 Seventh Ave.
New York, NY 10001
1-800-813- HOPE
(212) 302-2400

(Basic cancer information, questions, research, anatomy and physiology)

Breast Cancer Center
(Links other support groups)


1. American Cancer Society

2. CancerNet

3. Chappuis, PO; Rosenblatt, J; Foulkes, WD. The influence of familial and hereditary factors on the prognosis of breast cancer. Annals of Oncology, Oct,1999, V10 (N10): 1163-1170.

4. Goodwin, PJ. Management of familial breast cancer risk. Breast Cancer Research and Treatment, Jul, 2000, 62:19-33.

5. Harrison’s Online
Chapter 84, section 6, page 6

6. Rauh-Adelmann, C; Lau, KM; Sabeti, N; Long, JP; Mock, SC; Ho, SM. Altered expression of BRCA1, BRCA2, and newly identified BRCA2 exon 12 deletion variant in malignant human ovarian, prostate, and breast cancer cell lines. Molecular Carcinogenesis, Aug, 2000, 28(4): 236-246.

7. Schwartz, AG; Siegfried, JM; Weiss, L. Familial aggregation of breast cancer with early onset lung cancer. Genetic Epidemiology, 1999, V17(N4): 274-284.

8. Valeri, A; et al. Early onset and familial predisposition to prostate cancer significantly enhance the probability for breast cancer in first degree relatives. International Journal of Cancer, Jun, 2000, V86 (N6): 883-887.