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Additional Information


This American Society of Clinical Oncology website provides information about seeking a second opinion, questions to ask your doctor and understanding a Pathology Report.



This website developed by the College of American Pathologists provides comprehensive information on how to read your breast cancer pathology report.


Y-Me Breast Cancer Support


The Dr. Susan Love Research Foundation

Provides extensive information about pathology reports, including an example of a typical report.


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your Pathology Report

Knowing some of the medical terms that doctors and pathologists use to describe a breast tumor will help you to better understand your pathology report.


Tumor Type

  • Adenocarcinoma: All breast cancers are adenocarcinomas. The prefix "adeno" means arising from a gland. An adenocarcinoma is a tumor developed in glandular tissue, such as the breast.
  • Ductal carcinoma in situ (DCIS): Ductal cancer cells that have not grown outside of their site of origin, sometimes referred to as a precancer.
  • Lobular carcinoma in situ (LCIS): Abnormal cells within the lobule that don't form lumps. They can serve as a marker of future cancer risk.
  • Invasive ductal carcinoma: What we commonly refer to as breast cancer. About 80 percent of all breast cancers are invasive ductal carcinoma.
  • Invasive lobular carcinoma: This type of breast cancer begins in the breast lobules. About 10-15 percent of breast cancers are invasive lobular carcinoma.

Tumor Size (T)

  • T1 = 0-2cm
  • T2 = 2-5cm
  • T3 = greater than 5cm
  • T4 = ulcerating through the skin or stuck to the chest wall

(Note: 2cm = 3/4 inch; 5cm = 2 inches)


Breast Tumor Biology

Hormone Receptor Status

  • Estrogen Receptor:  Described as positive or negative; written as ER+ or ER-.
  • Progesterone Receptor:  Described as positive or negative; written as PR+ or PR-.

Breast cancer cells can have hormone receptors for estrogen and progesterone. Tumors that are ER+ or PR+ are fueled by estrogen. Some trials require patients to be ER+; some require patients be ER+ and/or PR+; and some require patients to be ER-.

HER2 Status
  • HER2, also known as HER2/neu and ErbB-2 (Human Epidermal growth factor Receptor 2): Described as positive or negative; written as HER2+ or HER2-.
Tumors that are HER2-positive produce too much of a protein called Her-2/neu. Some trials require patients to be HER2+; some require patients to be HER2-; and some enroll patients who are HER2+ or HER2-.


If you have additional questions about any of your medical reports, you should speak with your physician or with the pathologist who wrote the report.