This topic takes on average 120 minutes to read.
Cancer is a non-communicable disease which occurs due to uncontrolled cell division, known as mitosis.
Mitosis is closely controlled by the genes inside every cell, but sometimes this control can go wrong. If that happens in just a single cell, it can replicate itself to make new cells that are also out of control. These are cancer cells. They continue to replicate rapidly without the control systems that normal cells have. Cancer cells will form lumps, or tumours, that damage the surrounding tissues.
Tumours can be either benign or malignant. Benign tumours are contained in one area and do not invade other parts of the body. However, malignant tumours are cancerous. They invade neighboring tissues and spread to different parts of the body through a process known as metastasis, forming secondary tumours elsewhere.
Cancer is often caused by gene mutations which can sometimes be caused by carcinogens. Changing just one or two bases in the DNA sequence can scramble the information and mean that the gene does not work properly. If the mutation is in a gene that controls cell division, it can trigger the uncontrolled replication of that cell. This faulty gene is copied to all the new cells and so the uncontrolled growth continues. Smoking exposes an individual to carcinogens, and that is why there is a correlation between smoking incidence and cancer.