The link between oestrogen and breast cancer

The incidence of breast cancer cases amongst Malaysians in 2018 was 7,593, representing 17.3% of all cancer cases that year.

In Malaysia, it is the leading cancer in women, followed by colorectal cancer. In a larger scale, it impacts up to 2.1 million women worldwide each year.

The hormone oestrogen is one of the risk factors which plays a role in the development of breast cancer.

What is oestrogen?

Oestrogen is a female sex hormone produced in the ovary. It plays an important role in the development of a female’s secondary sexual characteristics aside from regulating the integrity of her reproductive organs.

Although it is produced in the ovary, the signal to produce it comes from the pituitary gland in the brain.

How oestrogen gives rise to breast cancer

The majority of breast cancers is influenced by the hormone oestrogen, said to be ER-positive. Sometimes, a big portion of ER-positive breast cancers will also be PR-positive.

The term “ER-positive” means positive for oestrogen receptor and the term “PR-positive” means positive for progesterone receptor.

Context-wise, it denotes the reaction of the breast cancer to the presence of the hormones.

Oestrogen binds to ER-α receptors and stimulates cells in the breast to divide. This constant division process has the probability of having a few cells mutate upon division.

These mutated cells in turn, will actively divide uncontrollably and after some time, the accumulated cells from this uncontrolled division, forms a cancer.

It can keep on growing until it invades nearby structures such as the ribs, underlying muscles and lymph nodes.

Usually, there are genes that regulate the division of cells, stopping any further division and killing off mutated cells.

However, when there’s genetic mutation that leads to the failure of these genes from regulating cell division, these cancer cells can keep on dividing.

What’s the treatment for ER-positive breast cancer?

Fortunately, ER-positive breast cancer has the best prognosis (chances of good outcome) compared with other forms of breast cancer.

One of the main treatments used for ER-positive breast cancer is Tamoxifen, a type of hormonal therapy that competes with oestrogen to bind at the oestrogen receptor.

It is advised that women undergo mammogram screening and regularly carry out self-breast assessment for early detection of lumps in the breast.

To know more about other risk factors, symptoms and treatment options, consult your doctor.

This article first appeared in hellodoktor.com. The Hello Health Group does not provide medical advice, diagnosis or treatment.