Out of this nearly 2% gets involved in criminal activities. In most other countries, the rate is much higher. 

A human being uses  more than 10,000,000,000,000,000. cells in his  life time. 

So a few cells going astray is not the  astonishing fact, but the magnanimous manner in which they are restricted to be loyal.
 

Fig 1 Cancer cells are similar to the traitors in a sovereign nation.

What causes cancer?

The cause of a cancer is not easy to be determined. But what ever the cause is a  cancer is a group of our own body cells in a hectic attempt to grow, multiply and propagate at the expense of all other cells and tissues. 

There are over 100 types of cancer. They are generally named according to the organs in which they originate.

•    Carcinoma - A cancer of the skin or in tissues that line the internal organs.
•    Sarcoma – Bone cancer, or may be in a cartilage, muscle, blood vessels, or other
                         connective tissue.
•    Leukemia - Blood cancer that develop in the bone marrow.
•    Lymphoma:- Cancer of the cells dwell in the lymphatic system.
•    Nerve cancers:- Cancer of the brain and spinal cord.

It is an inherent quality of the living things to grow.  This occurs by a process called cell division.. Replication (making faithful copies of itself ) is the unique characteristic of the DNA molecule. 

The cells of uni-cellular and multi-cellular organisms go on dividing either for reproduction (binary fission) or for growth. Normal body cells termed as somatic cells multiply to increase the size of an organ or to replace worn out cells. Cells for reproduction, gametes (sperms and eggs) are produced in organs specialized for the purpose only. 

It’s a wonder that, generally no cancer occurs in these cells in spite of a very high rate of division in producing sperms!

Consider this child.  Her hand has to grow. 

So the skin cells, muscle cells, along with her bone cells must divide and multiply according to a plan. On reaching adulthood does the process stop ? 

The old  skin cells get peeled off and new layer takes the place every two weeks. If a  a muscle gets cut the wound has to be healed by new cells. 

If a bone gets fractured new bone cells must produce and fuse the bone. In an adult although the cells do not multiply as in a child, there are cells capable of growing new tissue. These are called adult stem cells. These are abundant under the skin., In linings of the alimentary canal and in the bone marrow . These are the most  vulnerable stations for different forms of cancer.

Cancer cells and stem cells are similar in many ways.                                                               Normal cells can go on dividing only a certain number of times but these have the ability to divide as long as nutrients and oxygen are available. 

When a stem cell divides producing two daughter cells only one goes on specializing for a particular duty. The twin sister is kept lodged in the safe haven. One that ventures after a certain number of divisions due to various signals it gets from the neighboring cells and due to the effect of suppressor enzymes  present, fit into a particular niche and functions as a member of a team in harmony with the neighbours. 

Ninety nine point nine times,  the stem cells will go on to develop smoothly. Sometimes, at some stage a truant may appear. Just as every effect should have had  a cause, there must have been some reason for this kind of derailment too. Most researchers attribute these to heredity. While this is plausible there can be a multitude of other reasons for a cell to go astray considering the  massive numbers involved.

Just a mutation of a gene is not going to produce a cancer. There are many ways to stop the progress of such a faulty gene. It may be repaired or failing that it could be forced to commit suicide. (apostosis) Analysis  of cancer cells have shown that there is a much bigger mix up of  genes than expected. Whole chromosomes have got deleted at times. Whereas a  human cell should have 23 pairs of chromosomes  some cells leading to cancers have been found with double or treble this number. This is called polyploidy.  One cancer researcher, William Hahn  has stated that , “The nucleus of a  tumour cell looks as if had been shattered by a bomb”. Robert A Weinberger who discovered the first cancer gene says ,  “Five or six regulatory systems have to be surpassed for a  normal cell to become cancerous”. 

When a clump of cells within a tissue divide endlessly the neighbouring cells apply pressure and give signals to stop.  Just as there are genes producing growth promoting proteins, another set of genes produce suppressor proteins. As the tumour cells heap up they get distanced from the blood capillaries  which should lead to oxygen and nutrient redundancy.

Sometimes cancer cells induce the blood capillaries to grow into the tumours. Another factor inhibiting endless division is the unit called the telomere present at the end of chromosomes. Every time a chromosome divides telomere gets wasted . Once the telomere has reduced to a critical size the replication should stop. Cancer cells overcome this factor too.

A tumour does  not always end up in cancer. There are two types of tumours. Benign and Malign. While benign tumours grow compressing the nearby tissue and does not proliferate. 

 
Once they are removed by surgery, they do not grow again. The malignant tumours once mature,  send their emissaries all over the body using the vascular systems. This process is called  metastasis

Prevention and treatment

Risk Factors:- Sm- Smoking, Al- Aalcohol, Ra- Radiation, Car- Carcinogens. He- heredity,   Pat- Pathogens.Ob- Obesity,Fat- Fatty food, Fri- Fried food,Se- Sedentary life.

Prevention:-  Ba- Balanced diet, Ex- Exercise , Te- Tests,

Treatment:- Ra- Radiation therapy, Ch:- Chemotherapy, Im.- Immuno therapy,  S- Surgery, 

Vi- Virotherapy.

Type

Risk Factors

Prevention

Treatment

Estimated  deaths in U.S  for  2009

Sm

Al

Ra

Car

He

Age

Pat

Ob

Fat

Fri

Se

Ba

Ex

Te

Fru

R.

Ch

Iy

Su

Viro

Lung cancer

X

X

X

X

X

X

X

X

X

X

159,400

Skin cancer

X

X

X

X

X

1,000

Breast

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

40,600

Bladder

X

X

X

X

X

X

X

X

X

X

X

X

X

14,300

Prostate

X

X

X

X

X

X

X

X

X

X

X

X

27,400

Leukemia

X

X

X

X

X

X

X

X

X

X

21,900

Colorectal

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

50,000

Pancreatic

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

35,200

Cervical

X

X

X

X

X

X

X

X

X

4,100

Reference:- Reliable on line sources, 

It was the general belief that cancer is in-curable.  The favourable grants made available by the developed countries and pharmaceutical firms and the humanitarian groups coupled with the persevering efforts of the doctors and researchers, catalyzed by the several Nobel Prizes awarded for achievements  has paid dividends. Let us consider a few of these options prior to touching what we consider as hammering the last nail in the cancer coffin.

CHEMOTHERAPY

This is the most common form of cancer treatment today. Chemical drugs are either given as pills or as injections. As the chemicals destroy or inhibit the growth of dividing cells side effects such as loss of hair, nausea fatigue and loss of appetite cannot be completely avoided. A special advantage of this method is that even after the cells have undergone metastasis. the chemicals can go after them. Tumours in an advanced state with well developed blood vessels are the most susceptible. Every year millions of people are being relieved by this treatment.

RADIOTHERAPY

Very energetic rays such as X rays are aimed at the cancer cells from an external machine. These damage the genes in the dividing cells. The normal cells in the path way can also get affected. Generally a period is allowed for them to repair themselves. The patients do not become radioactive by this method. A variation is to implant a radioactive isotope such as, iodine 131 inside the body adjacent to the cancer. This will kill only  the cells nearest the source by continuous emanation of radioactive rays. Here some precautions have to be taken by the people around as the patient will become a carrier of a radioactive source.

BIOTHERAPY (IMMUNE THERAPY)

Immune therapy uses our own defensive cells in the blood and lymph to fight invaders ,  such as . T-cells, NK-cells, and macrophages to suppress the fast dividing cancer cells. These cells once they learn to recognise the cancer cells can be employed to hunt the spreading cells during metastasis.

VIROTHERAPY

If a doctor suggests using a virus against cancer the patient may end up in jitters. Such is notorious name earned  by these deadliest pathogens that the human kind has ever encountered. Diseases ranging from Small pox, Ebola fever, Hepatitis  to AIDS, measles and swine flu,

 
The initiation to virotherapy was due to the healing effects observed in cancer patients who had contacted measles. In 2006  Professors Amos Panet and Zichria Zakay-Rones  at the Hebrew University discovered a virus that attacks cancer cells. They have conducted experiments with a viruses of this kind  against tumour cells for several years.  Viruses insert their genes into a  cell and using the molecular machinery of the host multiply its own kind and the progeny escape rupturing the host cells. Pathogenic viruses have their own specific cells to get attached to. NDV-HUJ viruses without going after normal body cells always seek cancer cells as their hosts.

National Cancer Institute study found viruses caused tumours to shrink in cervical cancer patients without adverse effects. "Viro therapy went from an idea to human clinical trials in something less than 24 months, It's being used very, very aggressively, and new technologies are being developed," says Dr. David  Curiel, at the University of Alabama. Dr. Robert L. Martuza, director of the neuro-oncology center at Massachusetts who has genetically engineered a herpes virus to cure mice of a form of brain cancer says "For the first time, we can harness these disease-causing viruses and make them into disease-curing viruses,". Leonard E. Post, senior V. P. at Onyx Pharmaceuticals The company was showing promise at treating advanced colorectal cancer with engineered viruses.