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|Podcast: Researchers discuss the latest findings from TCGA’s study on the four types of breast cancer (3:43)|
What is breast cancer?
This cancer starts in the tissues of the breast. Breast cancer is the most frequently diagnosed cancer and the second cause of cancer deaths in women. In 2010, 207,090 women were estimated to have been diagnosed with invasive breast cancer in the United States and approximately 40,000 women were estimated to have died of their disease.1 Men can also have breast cancer, although male breast cancer is rare. In 2010, 1,970 American men were estimated to have been diagnosed and 390 were estimated to have died of breast cancer.1 Due to early detection through use of mammograms and improvements in treatment, breast cancer deaths have steadily decreased since the 1990s. View additional information on breast cancer.
The Cancer Genome Atlas (TCGA) program will focus mostly on two types of invasive breast cancer: ductal carcinoma and lobular carcinoma. Invasive ductal carcinoma is the most common type of breast cancer. It comprises about 65 to 85 percent of all breast cancer and develops in the milk ducts of the breast. About 10 percent of all cases of advanced breast cancer2 are invasive lobular breast carcinoma. This cancer develops in the breast milk-producing lobules or glands.
What have The Cancer Genome Atlas (TCGA) researchers learned about lobular carcinoma?
TCGA researchers have:
- Identified genomic characteristics of lobular carcinoma that distinguish it from the more common ductal carcinoma and suggest opportunities for targeted therapy
- All lobular carcinoma tumors were defined by loss of cell-to-cell adhesion protein E-cadherin through varied routes of genomic disruption
- Lobular carcinomas demonstrated frequent mutations in different genes involved in estrogen receptor signaling compared to ductal carcinoma, suggesting that these tumor types may rely on different mechanisms to activate estrogen receptor-mediated gene expression
- Lobular carcinomas contained a greater degree of Akt signaling pathway activation than ductal carcinomas, indicating that lobular carcinoma may have increased sensitivity to Akt pathway inhibitors
- Delineated three subtypes of lobular carcinoma, reactive-like, immune-related, and proliferative, that showed distinct clinical outcomes
- The reactive-like subtype was associated with the best outcomes and the proliferative was associated with the poorest
- Demonstrated that tumors that could not be identified as lobular or ductal based on their histology, or their appearance under the microscope, were not a distinct subtype, as they could be grouped with either lobular or ductal types based on their molecular features
Where can I find more information about the TCGA Research Network's studies or studies using TCGA data?
Where can I find clinical trials to treat breast cancer that are supported by the National Cancer Institute (NCI)?
View a list of NCI-supported breast ductal carcinoma clinical trials or breast lobular carcinoma clinical trials that are now accepting patients.
1American Cancer Society: Cancer Facts and Figures 2010. Atlanta, GA: American Cancer Society, 2010. Statistics for invasive breast cancer estimated new cases and deaths.
2Wood WC, Muss HB, Solin LJ, Olopade OL: Malignant Tumors of the Breast In: DeVita VT Jr, Hellman S, Rosenberg SA, eds.: Cancer: Principles and Practice of Oncology. 7th ed. Philadelphia, Pa: Lippincott Williams & Wilkins, 2005, pp 1420.