Are your cancer cells fueled by hormones?

Some breast cancers are sensitive to your body's naturally occurring female hormones — estrogen and progesterone. The breast cancer cells have receptors on the outside of their walls that can catch specific hormones that circulate through your body.

Knowing your breast cancer is sensitive to hormones gives your doctor a better idea of how best to treat the cancer or prevent cancer from recurring.

Hormone status of breast cancers includes:

  • Estrogen receptor (ER) positive. This type of breast cancer is sensitive to estrogen and may respond to hormone therapy.
  • Progesterone receptor (PR) positive. This type of breast cancer is sensitive to progesterone and may respond to hormone therapy.
  • Hormone receptor (HR) negative. This type of cancer doesn't have hormone receptors, so it won't be affected by treatments aimed at blocking hormones in the body.

What is the genetic makeup of your breast cancer cells?

Doctors are just beginning to understand how the individual DNA changes within cancer cells might one day be used to determine treatment options. By analyzing the genes of cancer cells, doctors hope to find ways to target specific aspects of the cancer cells to kill them.

Laboratory testing can reveal certain genes in your cancer cells, such as:

  • HER2 gene. Cancer cells that have too many copies of the HER2 gene produce too much of the growth-promoting protein called HER2. Targeted therapy drugs are available to shut down the HER2 protein, thus slowing the growth and killing these cancer cells.
  • Other genes. Researchers are studying ways to interpret the genetic makeup of tumor cells. Doctors hope this information can be used to predict which cancers will spread and which may need aggressive treatments. That way, women with relatively low-risk breast cancers may avoid aggressive treatments.

    Tests that analyze the genetic makeup of breast cancers are available but aren't recommended in all situations. Ask your doctor whether this type of test might be helpful in your case.

Doctors are increasingly using genetic information about breast cancer cells to categorize breast cancers. These groups help guide decisions about which treatments are best. Breast cancer groups include:

  • Group 1 (luminal A). This group includes tumors that are ER positive and PR positive, but negative for HER2. Luminal A breast cancers are likely to benefit from hormone therapy and may also benefit from chemotherapy.
  • Group 2 (luminal B). This type includes tumors that are ER positive, PR negative and HER2 positive. Luminal B breast cancers are likely to benefit from chemotherapy and may benefit from hormone therapy and treatment targeted to HER2.
  • Group 3 (HER2 positive). This type includes tumors that are ER negative and PR negative, but HER2 positive. HER2 breast cancers are likely to benefit from chemotherapy and treatment targeted to HER2.
  • Group 4 (basal-like). This type, which is also called triple-negative breast cancer, includes tumors that are ER negative, PR negative and HER2 negative. Basal-like breast cancers are likely to benefit from chemotherapy.

Understanding more about the chemical and genetic makeup of your cancer may help doctors choose the most effective treatment for your specific cancer.

Feb. 06, 2015 See more In-depth