Hey, Its Nathania here, right below this is a general explanation of what cancer is. I am sure most of you have heard this term before, but what is it actually. So, don't stall and read the explanation down below.
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.
How cancer arise?
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.
When cancer spreads.
A cancer that has spread from the place where it first started to
another place in the body is called metastatic cancer. The process by
which cancer cells spread to other parts of the body is called
metastasis.
Metastatic cancer has the same name and the same type of cancer cells
as the original, or primary, cancer. For example, breast cancer that
spreads to and forms a metastatic tumor in the lung is metastatic breast
cancer, not lung cancer.
Under a microscope, metastatic cancer cells generally look the same
as cells of the original cancer. Moreover, metastatic cancer cells and
cells of the original cancer usually have some molecular features in
common, such as the presence of specific chromosome changes.
Treatment may help prolong the lives of some people with metastatic
cancer. In general, though, the primary goal of treatments for
metastatic cancer is to control the growth of the cancer or to relieve
symptoms caused by it. Metastatic tumors can cause severe damage to how
the body functions, and most people who die of cancer die of metastatic
disease.
Source:
https://www.google.com/search?q=the+science+behind+cancer&safe=strict&client=firefox-b-d&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjNqur3m-PhAhWq4XMBHcS6DJEQ_AUIECgD&biw=1920&bih=962#imgrc=1Xe-s70LR9qQFM:
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.
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.)
Under a microscope, metastatic cancer cells generally look the same
as cells of the original cancer. Moreover, metastatic cancer cells and
cells of the original cancer usually have some molecular features in
common, such as the presence of specific chromosome changes.
