Saturday 9 July 2011

HOW A CANCER GROWS

How a cancer grows

This page tells you how cancers grow within the area of the body they started in. There is information on
  • How cancers grow locally
  • Where cancers spread locally

How cancers grow locally

As a tumour gets bigger, it takes up more and more room in the body. Soon it begins to grow into the body structures nearby. This is called local invasion. How a cancer actually grows into surrounding normal body tissues is not fully understood. But research has pointed to 3 ways that the tumour is most likely to do this
  • Pressure from the growing tumour
  • Using enzymes
  • Cancer cells moving through the tissue
A particular tumour will probably use all 3 of these ways of spreading. Which way is used most will depend partly on the type of tumour, and partly on where in the body it is growing.

Pressure from the growing tumour

As the tumour grows and takes up more space, it begins to press on the normal body tissue nearby. The tumour growth will force itself through the normal tissue, as in the diagram below.
TruTone.jpg
The finger like appearance of the growth happens because it is easier for the growing cancer to force its way through some paths than others - for example. tumours may grow between sheets of muscle tissue rather than straight through one particular sheet. As the cancer grows, it will squeeze and block small blood vessels in the area. Due to low blood and oxygen levels, some of the normal tissue will begin to die off. This makes it easier for the tumour to continue to push its way through.

Using enzymes

Many normal blood cells produce chemicals called enzymes that break down cells and tissues. The blood cells use their enzymes to attack invading bacteria and viruses. They also use them to break down and clear up damaged areas in the body. The damaged cells have to be cleared away so that the body can replace them with new ones. This is all part of the natural healing process.
Many tumours contain larger amounts of these enzymes than is usual in normal tissues. It is possible that the enzymes are made and given out by the cancerous cells. But some tumours also contain a lot of normal white blood cells. They are there because they are part of the immune response of the body to the tumour. We don't know exactly where the enzymes come from. But growing tumours seem to have high levels of enzymes that break down tissue. These enzymes are likely to make it easier for the tumour to make a pathway for itself through the healthy tissue.

Cancer cells moving through the tissue

One of the things that makes cancer cells different to normal cells is that they can move about more easily. So it seems likely that one of the ways that cancers spread through nearby tissues is by the cells directly moving. Scientists have discovered a substance made by cancer cells which stimulates them to move. They don't know for sure yet, but it seems likely that this substance plays a big part in the local spread of cancers.
This research is exciting because, if a substance has been found that helps cancer cells move, then research can start to find ways to stop the substance working. Research may also be able to find ways to stop the cancer cells making the substance in the first place. If cancers can be stopped from spreading, then it might be much easier to cure them.
Where cancers spread locally
A cancer probably just grows out in a random direction from the place where it started. However, tumours can spread into some tissues more easily than others. For example, large blood vessels that have very strong walls and dense tissues such as cartilage are hard for tumours to grow into. So locally, tumours grow along the 'path of least resistance'. This means that they probably just take the easiest route.

WHAT CANCER IS

http://www.youtube.com/watch?v=hJrZp2I7TEY&feature=related

What cancer is

Cancer is a disease caused by normal cells changing so that they grow in an uncontrolled way. The uncontrolled growth causes a lump called a tumour to form. If not treated, the tumour can cause problems in one or more of the following ways
  • Spreading into normal tissues nearby
  • Causing pressure on other body structures
  • Spreading to other parts of the body through the lymphatic system or bloodstream
There are over 200 different types of cancer because there are over 200 different types of body cells. For example, cells that make up the lungs can cause a lung cancer. There are different cells in the lungs, so these may cause different types of lung cancer. There is more about types of cells and cancer in this section of  Cancer Help UK.

Normal cells

Your body is made up of billions of cells that can only be seen under a microscope. These cells are grouped together to make up the tissues and organs of our bodies. They are a bit like building blocks.
cells
Different types of body tissues are made up of different types of body cells. For example, there are bone cells in bone and breast cells in the breast.
 

Genes and cancer

Different types of cells in the body do different jobs, but they are basically similar. They all have a centre called a nucleus. Inside the nucleus are the genes. Genes are really bits of code. The information they carry can be switched on or off. The genes control the cell. They decide when it will reproduce, what it does and even when it will die.
normal cellNormally the genes make sure that cells grow and reproduce in an orderly and controlled way. If the system goes wrong for any reason, the usual result is that the cell dies. Rarely, the system goes wrong in a way that allows a cell to keep on dividing until a lump called a 'tumour' is formed. There is information about the differences between normal cells and cancer cells in this section of CancerHelp UK.
 

Benign and malignant tumours

Tumours (lumps) can be benign or malignant. Benign means not cancer. Benign tumours
  • Usually grow quite slowly
  • Do not spread to other parts of the body
  • Usually have a covering made up of normal cells
Benign tumours are made up of cells that are quite similar to normal cells. They will only cause a problem if they
  • Grow very large
  • Become uncomfortable or unsightly
  • Press on other body organs
  • Take up space inside the skull (for example, like a brain tumour)
  • Release hormones that affect how the body works
Malignant tumours are made up of cancer cells. They
  • Usually grow faster than benign tumours
  • Spread into and destroy surrounding tissues
  • Spread to other parts of the body
The diagram below shows  a tumour appearing in cells lining a body structure such as the bowel wall. The tumour grows through the layer holding the cells in place (the basement membrane) and spreads into the bloodstream.
cancer cells breaking away
It is the ability to spread that makes a cancer harmful. If a cancer is not treated, it can spread into the organs near to where it started growing. It can also damage other parts of the body that it spreads to.
 

Primary and secondary cancer

primary and secondary cancer
The place where a cancer begins is called the 'primary cancer'. Cancers may also spread into nearby body tissues. For example, lung cancer can spread to the lining of the chest, the pleura. Ovarian cancer can spread to the lining of the abdomen (the peritoneum). This is called locally advanced cancer.
Cancer cells can break away from the primary tumour and be carried in the blood or lymphatic system to other parts of the body. There they can start to grow into new tumours. Tumours from cancers that have spread are called 'secondary cancers' or 'metastases' (pronounced met-as-tah-seez). A cancer that has spread has 'metastasised'.
The various organs of the body are made up of different types of cells. Any of these cell types can grow into a primary cancer. Different types of cancer behave very differently. The type of cancer affects whether it is
  • Likely to grow quickly or slowly
  • Likely to produce chemicals that change the way the body works
  • Likely to spread in the blood or lymph system
  • Likely to respond well to particular treatments
 

Cancer symptoms

Cancers can cause different symptoms according to where they are in the body. A cancer may press on a nerve, or another nearby body organ. It may also cause symptoms by releasing chemicals or hormones into the bloodstream. You can find out about the symptoms for each type of cancer in our section about specific cancers.

TERAPI KANSER B17

Kisah Seniwati Datuk Sarimah Ahmad yang semakin pulih setelah menerima terapi rawatan B17 (di samping minum air zam zam) ekoran diserang kanser otak, hidung dan lidah pada tahap empat memang cukup mengejutkan. - Fakta daripada i SIHAT keluaran Julai 2011

iSIHAT Edisi Julai 2011


 - Info Kesihatan telah memaparkan dan mengupas keberkesanan serta kewujudan Vitamin B17'.