CELL DIVISION GOING WRONG: Cancer 2.7 Cancer is a group of diseases that result from uncontrolled cell growth. The result is a change in the DNA that controls the cell cycle. This change prevents the cell from staying in interphase for the normal period of time. When the normal checkpoints fail, the cell and its daughter cells will divide uncontrollably

Uncontrolled growth may create a rapidly growing mass of cells that form a lump, or tumor Tumours may be benign or malignant. Cells in a malignant tumour are considered cancerous. Cancer cells may break away from the original tumour and move to a different part of the body. If they settle and grow in this new location, a new tumour will form. This process of breaking away and creating secondary tumours is called metastasis 2.7

When cells divide, their DNA is almost always duplicated error-free When cells divide, their DNA is almost always duplicated error-free. The genetic information in their daughter cells is identical to the parent cell. Sometimes random changes occur in the cell’s DNA. These changes are called mutations. Changes may result in the death of the cell or allow it to survive and continue to grow and divide. If the cell cycle is abnormal, the cells may be cancerous.

Causes of Cancer Sometimes when cells divide, mutations occur. Mutation: a random change in the DNA Some mutations are caused by carcinogens: environmental factors that cause cancer. Some well-known carcinogens include: Tobacco smoke Radiation (X-rays and UV rays from tanning beds and sunlight) Viruses, such as human papillomavirus (HPV) and hepatitis B Certain chemicals in plastics Many organic solvents

Lung cancer is the most common type of cancer in Canadians over 40 years of age. Health Canada reports that 9 out of 10 lung cancer cases are caused by smoking. The figure below identifies other parts of the body that are affected by the carcinogens in tobacco smoke. Some cancers are at least partly hereditary. These include some breast cancers and colon cancers. 2.7

Reducing Your Risk of Cancer 2.7 Cancer risks can be reduced through avoiding carcinogens and by making healthier lifestyle choices. Risk factors associated with cancer include Personal and family medical history Exposure to carcinogens in the environment Lifestyle choices, such as eating a healthy diet including a lot of fruits and vegetables “super foods and less fatty meat may help. Super foods such as these help your body protect itself from cancers

Diagnosis 2.7 Cancer screening means checking for cancer even when no symptoms are present. Screening can be performed at home, as part of a routine self-examination by a doctor, such as a Pap test or blood test as genetic testing, when there is a family history of cancer Other screening tests include skin checks by a doctor or dermatologist to look for changes in moles, new growths, and sores. While screening does not prevent cancer, it does increase the likelihood of early detection and successful treatment. The earlier a cancer is diagnosed, the better the chances of successful treatment. Some diagnostic imaging techniques include endoscopy, X-ray, ultrasound, CT scanning, and MRI.

Treatment 2.7 Once an abnormality has been identified, a sample of the cells is removed and examined under a microscope. This is called a biopsy. This is the only way to positively confirm a diagnosis of cancer. The purpose of cancer treatment is to slow down the growth of tumours or destroy as many cancer cells as possible. Currently, there are three methods of conventional treatment: Surgery (physically removing cancerous tissue) Chemotherapy (use of drugs) radiation therapy (Ionizing radiation) One new technique to fight cancer is biophotonics, which uses beams of light to detect and treat the cancer cells. Vocabulary Pap test