One of Current Major Problem in the World
Cancer is a group of diseases involving abnormal cell growth
with the potential to invade or spread to other parts of the body. Not all
tumors are cancerous; benign tumors do not spread to other parts of the body.
Cancer is the name given to a collection of related
diseases. In all types of cancer, some of the body’s cells begin to divide
without stopping and spread into surrounding tissues.
Cancer can start almost anywhere in the human body, which is
made up of trillions of cells. Normally, human cells grow and divide to form
new cells as the body needs them. When cells grow old or become damaged, they
die, and new cells take their place.
When cancer develops, however, this orderly process breaks
down. As cells become more and more abnormal, old or damaged cells survive when
they should die, and new cells form when they are not needed. These extra cells
can divide without stopping and may form growths called tumors.
Many cancers form solid tumors, which are masses of tissue.
Cancers of the blood, such as leukemias, generally do not form solid tumors.
Cancerous tumors are malignant, which means they can spread
into, or invade, nearby tissues. In addition, as these tumors grow, some cancer
cells can break off and travel to distant places in the body through the blood
or the lymph system and form new tumors far from the original tumor.
Unlike malignant tumors, benign tumors do not spread into,
or invade, nearby tissues. Benign tumors can sometimes be quite large, however.
When removed, they usually don’t grow back, whereas malignant tumors sometimes
do. Unlike most benign tumors elsewhere in the body, benign brain tumors can be
life threatening.
lung cancer cells
How Cancer Arises
Cancer is a genetic disease—that is, it is caused by changes
to genes that control the way our cells function, especially how they grow and
divide.
Genetic changes that cause cancer can be inherited from our
parents. They can also arise during a person’s lifetime as a result of errors
that occur as cells divide or because of damage to DNA caused by certain
environmental exposures. Cancer-causing environmental exposures include
substances, such as the chemicals in tobacco smoke, and radiation, such as
ultraviolet rays from the sun. (Our Cancer Causes and Prevention section has
more information.)
Each person’s cancer has a unique combination of genetic
changes. As the cancer continues to grow, additional changes will occur. Even
within the same tumor, different cells may have different genetic changes.
In general, cancer cells have more genetic changes, such as
mutations in DNA, than normal cells. Some of these changes may have nothing to
do with the cancer; they may be the result of the cancer, rather than its
cause.
"Drivers" of Cancer
The genetic changes that contribute to cancer tend to affect
three main types of genes—proto-oncogenes, tumor suppressor genes, and DNA
repair genes. These changes are sometimes called “drivers” of cancer.
Proto-oncogenes are involved in normal cell growth and
division. However, when these genes are altered in certain ways or are more
active than normal, they may become cancer-causing genes (or oncogenes),
allowing cells to grow and survive when they should not.
Tumor suppressor genes are also involved in controlling cell
growth and division. Cells with certain alterations in tumor suppressor genes
may divide in an uncontrolled manner.
DNA repair genes are involved in fixing damaged DNA. Cells
with mutations in these genes tend to develop additional mutations in other
genes. Together, these mutations may cause the cells to become cancerous.
As scientists have learned more about the molecular changes
that lead to cancer, they have found that certain mutations commonly occur in
many types of cancer. Because of this, cancers are sometimes characterized by
the types of genetic alterations that are believed to be driving them, not just
by where they develop in the body and how the cancer cells look under the
microscope.
Cancer Treatment
There are many types of cancer treatment. The types of
treatment that you have will depend on the type of cancer you have and how
advanced it is. Some people with cancer will have only one treatment. But most
people have a combination of treatments, such as surgery with chemotherapy
and/or radiation therapy. You may also have immunotherapy, targeted therapy, or
hormone therapy.
Clinical trials might also be an option for you. Clinical
trials are research studies that involve people. Understanding what they are
and how they work can help you decide if taking part in a trial is a good
option for you.
When you need treatment for cancer, you have a lot to learn
and think about. It is normal to feel overwhelmed and confused. But, talking
with your doctor and learning all you can about all your treatment options,
including clinical trials, can help you make a decision you feel good about.
Our Questions to Ask Your Doctor About Treatment may help.
(Last day i did not attend PPD session..I went to Maharagama Cancer Hospital with my mother to see a patient.so i think to write Article about Cancer)
