Our body is made of basic building blocks that called cell. When this cell mutates and becomes not normal anymore, it is becomes cancerous. In short, cancer is a disease of the cells.
The genetic instructions are present in every one of this cell of the body, and these instructions will control the cells lives and behavior, and tell our cells when and how to grow, reproduce and die. If those instructions get garbled, a cell may start behaving in a wired way and reproducing in an uncontrolled way.
This phenomenon is called mutation and when this happens, it is called cancer.
How does a cell become cancerous?
All types of cancer start from a single cell that undergoes quite a number of changes. Some of those changes are permanent
alterations to the DNA, called mutations. When this happens the mutated cell will try to start to reproduce itself in an
uncontrolled way. However, the human body is equipped with a host of defensive strategies for ensuring the mutated or
damaged cells never get the chance to reproduce. Thanks to these body natural defense systems, a potentially cancerous
has to make it past so many of these defenses before it can start to reproduce itself. This may take years, even decades
before that damage cell can have chance to pass through all the defenses. Those damaged cells which could not get through
will just be disposed by the defense system. There could be thousands and thousands of these damaged cells being disposed by
our body immunes system over our life time before they can cause any harm.
But if a cell able to get pass all of our defense systems, it will start reproduces itself without our body control,
and eventually form a mass of abnormal cells called a tumor. By the time a tumor is detected, it could already have billions
of cells duplicated in it. Cancerous cells produce growth factors which will stimulate blood vessels to grow near them, and
enabling the tumor to build itself a nourishing blood supply. In the later stages of cancer, those cancel cell will break off
form the tumor and spread via blood or lymph vessels to seed a secondary tumors in other parts of the body. By the time a
tumor is detected, it will contain billions of cells. Cancerous cells produce growth factors that stimulate blood vessels
to grow near them, enabling the tumor to build itself a nourishing blood supply.
What causes cancer
Cancer is rarely triggered by a single factor. It usually results from an interplay between environmental factors,
such as carcinogens or viruses and factors within the body such as hormones and inherited genes. Among numerous carcinogen,
tobacco towers over the rest as the biggest killer. It is said to be responsible for a third of all cancer deaths.
Researchers estimate that a further one third of cancer deaths can b e blamed on other "lifestyle" factors, such as diet a
nd obesity. Viruses can cause cancer by interfering with the genetic instructions in cells. The worst culprits for this
are the hepatitis B virus, which can cause liver cancer, and the human papillomavirus, which can cause cervical cancer.
The risk of developing cancer increases with age, simply because cancerous changes in cells usually take years to occur.
Types of cancer
There are perhaps 200 different types of cancer, but many are rare. The most common cancers among Singapore men: prostate, lung and bowel, which is also known as colorectum. For Singapore women, the most prevalent is breast cancer, followed by lung cancer and bowel cancer. The no.1 killer among all these is lung cancer, for both men and women.
Cancer treatment
Chemotherapy, which uses drugs to destroy cancer cells, and radiotherapy are the main treatments for cancer. But new treatments, including called "small-molecule drugs" or "targeted therapies" are being used by doctors to interrupt the signals inside cancer cells. Some of the drugs work by blocking signals that tell cancer cells to grow and divide uncontrollable. Others send signals to cancer cells to die. There are also drugs that can stimulate the immune system to recognize and destroy cancer cells.
