Cancer (GCSE Biology)

Cancer

Mutations and Cancer

• Cancer involves the formation of a tumour. Cancer involves the uncontrolled growth and division of cells. This forms a large cluster of cells called a tumour.
• Cancer is due to mutations. Why do cells start to grow uncontrollably? Well, often when cells divide there can be a change in the genetic material, which is called a mutation. Sometimes, this makes a cell divide very fast and out of control, leading to formation of a tumour.

Types of Tumour

Benign Tumours

• Benign tumours are formations that stay localised. Tumours do not have to be cancerous. Benign tumours can form from uncontrolled cell divisions. However, these tumours do not move from their site of origin and are often contained in one area. Benign tumours are not normally dangerous.

Malignant Tumours

• Malignant tumours are cancerous. Some tumours spread from their site of origin. These are malignant tumours, and they invade neighbouring tissue. They can also spread through the blood and form secondary tumours in other parts of the body. This is metastasis. They also invade the tissues near to them.

Lifestyle Risk Factors

• There are risk factors for cancer. The incidence of cancer can be increased by certain factors. Carcinogens, such as cigarette smoke, ionising radiation and viral infection can increase the risk of cancer e.g.
  HPV can increase the risk for developing cervical cancer.
• There are genetic risk factors for cancer. Genes can lead to an increased risk of cancer. For example, women with the BRCA gene are predisposed to breast cancer.