The human body is made up of Cells. In These cells uncontrolled growth and division any ware
in a body is caused Cancer. These Extra cells growth called tumors and these abnormal cells are
cancer cells, tumor cells or malignant cells.

Naturally Most of the normal cells have specific functions and particular life spam. These normal
cells receive instructions to die (apoptosis) and new cells produced.

But these cancer cells different from normal cells, grow out of control and spread quickly.
Normal cells are matured, well defined with specific functions. But cancer cells are not, these are
ignored the signals of dividing and program of cell death. To this reason cancer cells are
continued to divide without stopping. These cancer cells influence normal cells and supply the
tumors, oxygen and nutrients for its growth in our body.

These cancer cells can also influence the immune system and caused other changes. Normally
immune system removes the damaged or abnormal cells from the body. But these cancer cells
hide from immunity system and use system to grow.

Causes for Cancer

There are many causes for cancer, but some are preventable. The American cancer society says
more than 40 percent of cancer causes can be prevented.

Smoking is the biggest cause of cancer. As for The American cancer society risk factors for
cancer are

  • Smoking – 19%
  • Obesity – 7.8%
  • Alcohol consumption – 5.6%
  • UV Radiation – 4.7%
  • Physical inactivity -2.9%
  • Poor diet – 1.9%

If people can change these factors, 42% cancer cases and 45% of deaths can be overcome.

Cancer is a genetic disease. Person’s genetic factors can contribute to the growth of cancer. A
persons DNA contain large no of genes. These genes tell their cells functions and when divide
and expire.

Changes in genes leads to errors in the instructions caused cancer. Genetic changes such as
mutation, cause cancer can be inherited from our parents.

A minority of cancers occurs inherited genetic mutation and majority of cancer are occurred due
to life style and environmental exposures.

Drivers of Cancer

The three main genes, if they get genetical changes help to cancer are proto-oncogenes, tumor
suppressor genes and DNA repair genes.

Proto-oncogenes may have many different functions in the cell. Some proto-oncogenes are
programmed for cell death (apoptosis) and some are programmed for cell growth. When these
genes are over acted than normal or altered by mutation they cause cancer causing genes
(oncogenes).

Tumor suppressor genes are also involved in cell growth, slow down the cell division and repair
DNA mistakes. When mutation occurs in genes tumor suppressor genes are divide uncontrolled
manner.

In human cells DNA damage is caused by both metabolism activities and environmental factors
like radiation. DNA repair genes are worked in fixing damages in damaged DNA. Mutations in
these genes may cause cells are cancerous.

A cancer that can spread from one part of the body to another part of the body is called
metastatic cancer. In this cancer cells from tumor are break away and travel first part to another
part of the body through bloodstream or lymph system.

Types of Cancer

According to the National Cancer Institute there are more than 100 types of cancers.

In this there are 10 most deadly cancers:

  1. Lung and bronchial cancer
  2. Colorectal cancer
  3. Breast cancer
  4. Pancreatic cancer
  5. Prostate cancer
  6. Leukemia
  7. Non – Hodgkin Lymphoma
  8. Liver and Intrahepatic bile duct cancer
  9. Bladder cancer
  10. Brain or nervous system brain cancer

And Kidney cancer, Skin cancer, Cervical cancer and Thyroid cancers are common types of
cancers.

1. Lung and bronchial cancer
The lungs are part of our respiratory system. There are two main types of lung cancers. They are
non – small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). These two
classifications are based on cells in tumor appearance. So these two types of cancers are grow,
spread and treated differently.

NSCLC (non – small cell lung cancer) are about 80 to 85% lung cancers. Smoking is the main
risk factor for NSCLC. In this, cancerous cells form in the tissues of the lung.
SCLC (small cell lung cancer) are about 10 to 15% lung cancers. Smoking is the main risk factor
for SCLC.

Bronchial adenoma is a rare type of lung cancer that spreads in lung airways and salivary glands.
Adenoma means non cancerous tumor. Although most bronchial adenoma are cancers.

2. Colorectal cancer
Colorectal cancer is cancer that starts polyp in colon or rectum. These polyps are sometimes
normal and sometime leads to cancer. These are also called colon cancer or rectum cancer
depends upon its position.

3. Breast cancer
Breast cancer is the second most common cancer in women. Breast cancer is a disease that
cancer cells form in the tissues of the breast. The most common type of breast cancer is ductal
carcinoma that starts in ducts. Another type of breast cancer is lobular carcinoma that starts in
lobes. This cancer is commonly found I both breast. Inflammatory breast cancer is an uncommon
type of breast cancer.

4. Pancreatic cancer
Pancreatic cancer is a disease it can develop two types of cancer cells of the tissues of the
Pancreas. One is exocrine and another is neuroendocrine cells.
Smoking habits and health history affect the risk factors of pancreatic cancer. Signs of
pancreatic cancer are diabetes, jaundice and unexplained weight loss.

5. Prostate cancer
Prostate is the one of the most common type of cancer in men. It can grow very slowly. It is
difficult to find in early stages.

Symptoms of the prostate cancer are pain during urination, trouble starts or stops while urination,
more frequent urination and blood in urine.

Prostate cancer is most common in older men.

6. Leukemia