Title: Understanding cancer
From a normal cell to a cancer cell—take 5 minutes to get the picture!
More than 60,000 billion cells make up the human body. They are the units that form
the tissues which make up our organs, like the liver, heart, and lungs.
When the body needs it, our cells split into 2 and replace those cells that are
defective or have come to the end of their lifespan. This makes it possible for
our tissues to preserve their shape and their respective functions, with the passage
of time.
Every cell is therefore programmed to multiply... and die.
This ordered but complex program is controlled by the center of the cell, the nucleus,
which contains chromosomes containing many genes made up of DNA.
Sometimes, some of these genes undergo a change. The nucleus then sends out abnormal
orders and the cell goes wrong. It multiplies uncontrollably and takes on a life
of its own.
Each new cell produced contains the same defect. The cells proliferate chaotically
and form a tumor.
This process may be short but is often long: 10 to 30 years may separate the birth
of a first abnormal cell from the appearance of a tumor of about 1 cubic centimeter.
The tumor forms many blood vessels in order to survive. These will supply the tumor
with oxygen and nutrients, allowing it to live and grow. This is what we call the
phenomenon of “angiogenesis.”
The tumor, however, only really becomes dangerous when the cancerous cells begin
to invade, through the vessels, into the adjacent areas and spread to the surrounding
organs.
These cells can then invade other parts of the body, multiply, and produce new tumors.
Metastasis is the term used for this spreading process.
But why does a cell become cancerous? There are many factors, and they can exist
to different degrees.
Factors have been identified, such as:
- Hereditary genetic anomalies,
- Exposure to some viruses (HIV; hepatitis B, C and D; papilloma virus; Epstein-Barr
virus)
- Exposure to toxic agents (chemical products, radiation, sun)
- Unhealthy behaviors such as the consumption of alcohol and tobacco, or a diet too
rich in fat and low in fruit and vegetables
Today, over 25 million people in the world live with cancer. 7 million die from
it each year. The disease represents the leading cause of mortality for those under
65.
Lung cancer is the most widespread, followed by breast cancer, colorectal, stomach,
and prostate cancer.
The means to combat cancer do, however, exist. These often complementary treatments
are used alone or in combination according to the type of cancer and its status.
The goal of the treatments is to make it possible to eliminate the tumor and cure
the patient in early-stage cancer, or like a chronic disease, to control its development.
There are mainly 3 kinds of treatment:
- Surgery consists of removing the tumor, in part or in its entirety.
- Radiotherapy exposes the tumor to radioactive rays, which prevent the diseased cells
from multiplying and destroys them.
- Chemotherapy consists of administering systemic medicinal substances to destroy
the cancerous cells or prevent them from spreading.
Chemotherapy and radiotherapy act on cancerous cells, but also on healthy cells,
which explains their side effects.
But today, better knowledge of the characteristics of cancerous cells makes it possible
to develop therapies that target the cancer development mechanisms more specifically.
Sanofi-aventis R&D is already present in all these areas, to fight against cancer
on all fronts.