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What Are the Causes of Breast Cancer?

Medically reviewed by John Paul Abrina, MD · Oncology · Davao Doctors Hospital

Written by Kristel Dacumos-Lagorza · Updated Mar 09, 2022

What Are the Causes of Breast Cancer?

Breast cancer was once a fatal disease, however, with all the advancements in medicine, scientists and researchers have discovered ways to treat it. Breast cancer is more prevalent in women aged 50 and above. Although breast cancer is one of the most common types of cancer in the world, its causes are still largely unknown. What are the causes of breast cancer?

What Is Breast Cancer?

Breast cancer starts when breast cells grow abnormally and rapidly multiply, forming a lump or tumor. Even though breast cancer is more prevalent in women, in rare circumstances, men can have it too.

The signs and symptoms of breast cancer do not manifest in the early stages, but it begins to become visible as it gets progressively worse. Take note, not all lumps or tumors in the breasts are malignant (cancerous). In fact, most biopsied breast tumors are benign (non-cancerous).

Nevertheless, it is still best to get yourself checked if you notice an unusual lump in your breasts. This is needed since there are still possibilities that benign tumors can be premalignant and can become cancerous in the future.

What Are the Causes of Breast Cancer?

What are the causes of breast cancer? The main culprit of breast cancer is the abnormal growth of breast cells. However, the main reason breast cancer develops is still unclear.

While the question “What are the causes of breast cancer?” remain unanswered, there are theories that lifestyle and environmental factors increase the chances of a woman developing cancerous cells.

In addition, hormonal causes of breast cancer might also be possible, but these claims still need further investigation and studies.

However, researchers have found that changes and mutations within the DNA might be the reason why normal breast cells become cancerous.

DNA and Breast Cancer

DNA mutations transform normal breast cells into cancerous cells. The DNA mutations result in gene changes, which may disrupt the normal cell cycle regulation.

When the cell cycle becomes erratic, cells will start to abnormally form and speed up cell division, which leads to cancer.

Hereditary mutations are DNA mutations inherited from parents, meaning mutations are present in your cells since the day you were born.

Some inherited mutations can increase your risks of hereditary cancers. These mutations are the root cause of why certain cancers run in families and also the main reason for childhood cancer.

Even though hereditary mutations can trigger certain cancers, it is not considered as the main cause of breast cancer.

Instead, the mutations that you acquire throughout your life can be the reason for your increased susceptibility to breast cancer.

The acquired DNA mutations or somatic mutations only exist in certain breast cells and are found in breast cancer cells. Somatic mutations are caused by environmental factors such as being exposed to radiation and cancer-causing substances.

However, as of today, the real causes of somatic mutations linked to breast cancer are still unknown.

Risks of Breast Cancer

The following factors can increase your vulnerability to breast cancer:

  • Gender. Being a woman makes you more susceptible to breast cancer.
  • Age. You are more likely to develop breast cancer as you age. Women ages 50 and above are at most risk of this condition.
  • Hereditary. There are certain hereditary mutations (BRCA1 & BRCA2) passed on by parents that might increase their children’s risk of breast cancer.
  • Family history. You are at risk of developing breast cancer if one of your first-degree relatives, or members of the family either from your mother’s or father’s side have been diagnosed with the same condition.
  • Personal history of breast cancer. Women who have had breast cancer in the past have a higher chance of getting the same cancer for the second time.
  • Past diagnosis of a non-cancerous tumor. A past diagnosis of benign breast tumors can increase a man’s and woman’s risk of developing breast cancer in the future.
  • Early menstruation and late menopause. Starting menstruation before the age of 12 and experiencing menopause after 55 makes a woman prone to acquiring breast cancerdue to a longer period of estrogenic stimulation.
  • Pregnancy. Women who have given birth at an older age and women who have never given birth (nulliparous) are both at risk of getting breast cancer because of uninterrupted estrogen exposure.
  • Radiation exposure. A woman has a very high risk of breast cancer if she receives exposure to too much radiation (radiation therapy) at a younger age.
  • Hormone therapy. Certain hormone replacement therapies (combine therapy) for menopausal women increase their risk of breast cancer.
  • Poor lifestyle. Drinking alcohol, obesity, and being inactive makes a woman more vulnerable to breast cancer.

How to Lower Your Risk

Even though the answer to what are the causes of breast cancer is still unclear, there are steps you can take on how to lower your risks of breast cancer.

If your risks of breast cancer result from your lifestyle, then maybe it’s time for you to change some ways. Here’s what you can do:

  • Consult your doctor for a breast cancer screening as soon as you feel a lump on your breasts.
  • Practice breast awareness
  • Limit your consumption of alcohol if you cannot eliminate it.
  • Be more physically active.
  • Achieve and maintain a healthier weight
  • Eat a healthy balanced diet
  • Do your research before undergoing any kind of hormone therapy.
  • Ask your doctor for medications that can help lower your risk of breast cancer.
  • Undergo a preventive surgery known as mastectomy or surgery to permanently remove the breasts.

What Happens When Breast Cancer Has Reached Stage 4?

Metastatic breast cancer (stage 4) is breast cancer that has spread past the breast to other parts of the body like the bones, liver, lungs, and brain.

What causes breast cancer stage 4? This condition occurs when cancer cells can break away from the tumor and travel its way out of the breasts through the bloodstream. Women who were diagnosed with early-stage breast cancer are more at risk of developing metastatic breast cancer.

Even though cancer cells spread to other organs in the body, it is considered as breast cancer and will be treated as breast cancer. Although metastatic breast cancer is not curable, there are different treatments available that can help relieve the condition.

Key Takeaways

Breast cancer is one of the most common cancers in women, and rarely, in men. It is important to know what are the causes of breast cancer, and how to detect it. If you notice lumps on your breasts, it is important to undergo screening immediately. Always remember not to self-diagnose, and consult your doctor right away.

Make sure to do all the necessary treatments and take all medications, as well as change some ways in your lifestyle to prevent your condition from getting worse.

Learn more about Breast Cancer here.


Hello Health Group does not provide medical advice, diagnosis or treatment.

Medically reviewed by

John Paul Abrina, MD

Oncology · Davao Doctors Hospital

Written by Kristel Dacumos-Lagorza · Updated Mar 09, 2022

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