What causes cancer?


Cancer is the name given to a large group of diseases. All types of cancer begin in cells, when the natural process of cell death and cell formation is disrupted. Cancerous cells, unlike normal cells, divide uncontrollably and do not die, often forming tumours. An exception are blood cancers, which do not form solid cancer tumours.

Tumour types

There are two types of tumours: benign and malignant.

Benign tumours are abnormal growths, but they are not cancer tumours. They cannot spread to other tissues, and do not grow back after being removed. Malignant tumours, on the other hand, are cancerous. They can spread to other parts of the body, and may even grow back when removed.

What causes cancer?

Cancer is caused by mutations of DNA within cells. Genes control the way cells in our bodies behave. Therefore if a gene has mutations, it may cause a cell to act abnormally. When this happens, the cell is at risk of becoming cancerous.

Genetic changes may be:

  • inherited from our parents
  • acquired during our lifetime.

Most gene mutations take place during our lives. Many of the causes of these mutations are lifestyle related, and can be easily controlled.


Smoking tobacco is a leading cause of lung cancer and many other types of this disease. Tobacco, much like arsenic and asbestos, is a carcinogen, meaning it is a substance capable of causing cancer. Smoking, or even being around someone who smokes, greatly increases your chances of getting lung cancer. As many as 80 to 90 percent of lung cancer cases are directly linked to smoking. 

Drinking alcohol

Drinking more than one alcoholic drink a day for women, and more than two for men, increases the risk of getting alcohol assisted cancer, which most commonly appears in the head or neck, esophagus, liver, and breasts.

Excess body weight

Excess body weight is the second biggest cause of cancer in the UK, therefore it is important to engage in physical activity and maintain a healthy diet. It is recommended to walk at least 10,000 steps a day and to eat as many non-processed foods (such as fresh fruits and vegetables, meats, fish etc.) as possible.

Sun exposure

Exposure to the sun and other types of radiation can also be very harmful, and eventually lead to skin cancer. You should not spend more than 20 consecutive minutes in direct sunlight, and if you do, make sure to use sunscreen.

Unprotected sex

Some infections transmitted during unsafe sex can greatly increase your risk of cancer. One of them, the HPV virus, is the cause of virtually all cervical cancer cases, around 3100 of which are diagnosed in the UK every year. HPV can also cause cancer of the throat and mouth, as well as cancers of other genital areas.

HIV, another sexually transmitted virus, can also increase your risk of cancer. HIV attacks the immune system, making it easier for other viruses (such as HPV or EBV) to attack the organism.

Being aware of cancer risk factors and avoiding them can greatly reduce your chances of getting cancer. Sometimes only a few small lifestyle changes can make you both healthier and happier!

Authors: Julia Kubiak, Małgorzata Korzeniewska


We cannot successfully fight against cancer without the support of our Donors.


Need help?

Oncological patients often struggle not only with the disease, but also with serious financial problems.