Breast Cancer Pathology Report


Estrogen Receptor 95% favorable
KI67 MIB-1 2% Borderline
DNA INDEX 1.00 Diploid

The hormone receptor status of your tumor helps guide your treatment plan. If your tumor is ER+ and/or PR+, treatments that prevent the cancer cells from getting the hormones they need to grow (such as tamoxifen or aromatase inhibitors) may stop tumor growth. Tumors that are ER- and PR- are not treated with hormone therapies.

The proliferation rate represents the percentage of cancer cells that are actively dividing. In general, the higher the proliferation rate, the more aggressive the tumor tends to be. The Ki-67 test is a common way to measure proliferation rate. MIB1 is the antibody most often used to label the Ki-67 antigen. You may see these terms on your pathology report. A higher value shows a higher proliferation rate.

DNA Index of 1.0 means that the cells are diploid and are similar to normal breast cells in their DNA content.  A DNA content that is aneuploid has an abnormal DNA content……… About 70% of breast cancers will be aneuploid and 30% will be diploid.  The 5 year disease free survival for women with diploid tumors is 88% and for women with aneuploid tumors is 68%. The 5 year disease free survival for patients with a diploid tumor and a low SPF is 90% ………

HER2/neu (human epidermal growth factor receptor 2), also called ErbB2, is a protein that appears on the surface of some breast cancer cells. It is an important part of the cellular pathway for growth and survival.

  • HER2/neu-positive (HER2+)tumors have many HER2/neu genes inside the cancer cells (also called HER2/neu over-expression) and a large amount of HER2/neu protein on the surface of the cancer cells
  • HER2/neu-negative (HER2-) tumors have few HER2/neu genes inside the cancer cells and little or no HER2/neu protein on the surface of the cancer cells

About 15 to 20 percent of breast cancers are HER2+ [29-30 ]. These breast cancers tend to be more aggressive than other tumors.

HER2/neu status helps guide your treatment plan. HER2+ cancers can benefit from trastuzumab (Herceptin) therapy, which directly targets the HER2/neu receptor. This type of therapy is not used to treat HER2- cancers.

Both the  American Society for Clinical Oncology  and the National Comprehensive Cancer Network  recommend HER2/neu testing for all tumors. HER2/neu status can be determined in two ways:

  1. Immunohistochemistry (IHC) testing which detects the amount of HER2/neu protein on the surface of the cancer cells
  2. Fluorescence in situ hybridization (FISH) testing which detects the number of HER2/neu genes in the cancer cells

Most often, IHC is the first test and if the score is +2 (or borderline), the tumor is sent for FISH testing to confirm the status.

Score is 0 or +1 Tumor is HER2-
Score is +2 Results are unclear and should be confirmed by FISH
Score is +3 Tumor is HER2+
Positive (amplified) The tumor is HER2+
Negative (non-amplified) The tumor is HER2-


One response to “Breast Cancer Pathology Report

  1. Pingback: My Hat Trick, er, uh, Walk-off | Cancer Isn't Pink

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