About Breast Cancer
Breast cancer originates in breast tissue and arises from the ductal tissue of the breast and, less commonly, the lobular tissue.1 There are several forms of breast cancer based, in part, on cellular and genetic characteristics.2
Types of Breast Cancer
- Overexpression of the HER2 protein classifies the breast cancer as HER2-positive and causes breast cancer cells to multiply, spread more rapidly, and survive longer than other breast cancers3
- Breast cancer cells that express hormone receptors for estrogen (ER) and/or progesterone (PR) are dependent on the signaling of those receptors2
- Some women have a more difficult-to-treat form of breast cancer known as "triple-negative," which means they test negative for 3 main receptors (HER2, ER, and PR)2
Each form of breast cancer has a different prognosis. The American Society of Clinical Oncology recommends that all women diagnosed with breast cancer have tumor marker tests, which can help identify which type of breast cancer a patient has and help determine the best
Breast Cancer Epidemiology
- Family history of breast cancer, or personal history of breast abnormalities, early age at first menstrual period, obesity, and physical inactivity can contribute to development of breast cancer5
- Inheritance of mutations in specific genes, such as BRCA1 and BRCA2 contributes to the relative risk of developing breast cancer5
- Prognosis of 5-year survival varies according to different characteristics5
- Only 23% of women with distant metastatic disease will live for 5 years5
- Women with HER2+ disease have a 5-year survival rate of 68%7
- 94% of women with HR+ disease can expect to live for 5 years2
- Women with triple-negative disease have a survival prognosis of 81% for 5 years2
Breast cancer is often detected early through the use of several exams, including self-exams and mammography exams.5 Additionally, there are biomarkers to predict risk for developing breast cancer that can contribute to early detection.4 However, there do remain less common symptoms including changes to the breast or nipple such as thickening, swelling, tenderness, skin irritation, redness, and scaliness that can potentially be misdiagnosed.5
1. US Department of Health and Human Services. National Cancer Institute. What you need to know about™ breast cancer.
www.cancer.gov/cancertopics/wyntk/breast/WYNTK_breast.pdf. Accessed April 14, 2011.
2. de Ruijter TC, Veeck J, de Hoon JP, van Engeland M, Tjan-Heijnen VC. Characteristics of triple-negative breast cancer. J Cancer Res Clin Oncol. 2011;137:183-192.
3. Press MF, Bernstein L, Thomas PA, et al. HER-2/neu gene amplification characterized by fluorescence in situ hybridization: poor prognosis in node-negative breast carcinomas. J Clin Oncol. 1997;15:2894-2904. PMID: 9256133
4. Cancer.net. What to know: ASCO’s guideline on tumor markers for breast cancer. www.cancer.net/. Accessed April 19, 2011.
5. American Cancer Society. Cancer Facts & Figures 2010. www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-026238.pdf. Accessed April 19, 2011.
6. American Cancer Society. Cancer Facts & Figures for African Americans.
www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-027765.pdf. Accessed on April 14, 2011.7. Curigliano G, Viale G, Bagnardi V, et al. Clinical relevance of HER2 overexpression/amplification in patients with small tumor size and node-negative breast cancer. J Clin Oncol. 2009;27:5693-5699. PMID: 19884553