Cancer

Cell Cycle Checkpoints A cell should remain in interphase and not divide if... - signals from surrounding cells tell the cell not to divide - there are not enough nutrients in the cell - the DNA has not yet been replicated - the DNA is damaged These checkpoints are regulated by special proteins

Cancer is... A group of diseases that results in uncontrolled cell division A result from the change of DNA that controls the cell cycle One or more of the checkpoints fails so the cell and all its subsequent daughter cells continue to divide uncontrollably

Definitions Tumour: a mass of cells resulting from rapid cell growth

Benign: tumours that stay confined in a small area, causing little damage Malignant: dangerous tumours that break away and move to other areas of the body

A normal cell will live for between 50 and 60 cellular divisions A normal cell will live for between 50 and 60 cellular divisions. Cancer cells are “immortal” because they never stop dividing. A normal cell will undergo apoptosis if it is damaged genetically, whereas a cancer cell will continue to divide.

Causes of Cancer When DNA is replicated sometimes the process is not perfect and random changes occur– this is called a mutation These changes can result in the death of a cell or allows the cell to divide rapidly until all the nutrients are used up Carcinogen: any environmental factor that can cause a mutation (cancer) Tobacco smoke, radiation (X-rays, UV rays), certain chemicals in plastics cancer video 1 cancer video 2

Screening If cancer runs in your family you can get tested for it early Especially if you are surrounded by certain carcinogens your whole life Screening does not prevent cancer but it increases the chance of detecting it and treating it successfully Self checks for unusual lumps

Endoscopy Using an endoscope (fibre optic cable that delivers light and a tiny camera) to look into a patient and search for and remove any abnormal growths Eg. Colon cancer

X-rays Are used to view bones and different tissues (lungs, breasts) X-rays can cause damage to DNA and are harmful to the cells of a growing fetus – pregnant woman do not get X-ray exams

CT Scan and MRI CT Scan: X-rays from multiple viewpoints are taken These are assembled digitally on a computer MRI: radio waves and a strong magnetic field create more detailed images in 3D

Treatments Surgery: removing the damaged cells (tumour) Chemotherapy: using drugs that stop/slow down the cells from dividing. Shrinks the tumour and spreads through the whole body to attack any unknown cancerous tissues. There are many side effects (hair loss, weakness). Radiation: since cancer cells divide rapidly they are damaged easily by certain radiations.