Hormone receptors and breast cancer

Some breast cancers use hormones  in the body to help them grow.

This type of breast cancer is called hormone receptor positive breast cancer.

Oestrogen is the main hormone that helps some breast cancers to grow.

Progesterone is another hormone that may affect some breast cancers.

Breast cells contain special proteins called hormone receptors. These receptors receive messages from hormones in the body and respond by telling the cells what to do.

The hormone receptors found in breast cells are called oestrogen receptors and progesterone receptors. 

Oestrogen is a hormone that plays an important role in the female reproductive system. Men also produce small amounts of oestrogen.

Breast cancer cells can contain oestrogen receptors. This is called oestrogen receptor positive or ER-positive breast cancer.

Most breast cancers are ER-positive.

When oestrogen receptors are found in breast cancer cells, they can use oestrogen to help the breast cancer to grow.

All invasive breast cancers are tested for oestrogen receptors using tissue from a biopsy or after surgery.

Treatment for ER-positive breast cancer

If your breast cancer is ER-positive, you will usually be offered hormone therapy.

Hormone therapies work in different ways to block the effect of oestrogen or reduce the amount of oestrogen in the body.

You may have hormone therapy to:

• Reduce the risk of breast cancer coming back after surgery
• Reduce the size of the cancer or slow down its growth
• Treat breast cancer that has come back or spread

Progesterone is another hormone that plays a role in the female reproductive system. Men also produce small amounts of progesterone.

Sometimes breast cancer cells contain progesterone receptors. This is called progesterone receptor positive or PR-positive breast cancer.

Invasive breast cancers should also be tested for progesterone receptors.

Treatment for PR-positive breast cancer

Most PR-positive breast cancers are also ER-positive. You will usually be offered hormone therapy if your cancer is both ER-positive and PR-positive.

The benefits of hormone therapy are less clear for people whose breast cancer is only PR-positive. Very few breast cancers fall into this category, but if this is the case, your treatment team will discuss with you whether hormone therapy is suitable.

If your breast cancer has no hormone receptors, it is hormone receptor negative.

If this is the case, hormone therapy will not be of any benefit and your treatment team will discuss other treatment options with you.