All living things are made up of cells. They are the smallest things that are capable of basic life-they take in nutrients when needed, they put out waste and they reproduce. Cells divide (reproduce) at least once during their life, sometimes dozens of times. Organisms rely on this, this is how they grow or repair themselves when they are damaged. A normal body has around 30 trillion cells.
Permanent gene mutations are what cause cells to malfunction. When this happens several times to the same cell it can become cancerous. This can take many years in some cases. A cancerous cell reproduces at different rates, but eventually they overcrowd the normal cells and turn into a tumor.
There are two types of tumors, benign and malignant. A benign tumor does not spread to other parts of the body, it stays in one place. Benign tumors are not dangerous and do not need to be removed, but if you would like to have it removed for appearance purposes or if it is uncomfortable it can be surgically removed very easily.
A malignant tumor is a tumor that can spread to other parts of the body which makes them very dangerous.
There are many different kinds of cancer and they all react differently to different types of treatments. Cancer cells can break away from a tumor and spread to other parts of the body. They usually spread through the blood or lymph systems. When this happens it is called metastasis. It doesn't matter where the cancer spreads to; it is still named after the part of the body where it started. For example if the cancer started in the breast and then spread to the lymphatic system it is defined as metastastic breast cancer. A recurrence is when the cancer returns after...