Cancer Starts in the Body and Spreads to Other Parts of the Body
A tumor is a mass of cancer cells that grows in the body and spreads to other parts of the body. The cells in a cancer are abnormal and grow out of control. When cancer spreads to a different part of the body, it is called metastasis. Cancer is a complex disease and can cause many different symptoms. It can affect any part of the body. Most people who have cancer have other health problems, too. These include infections, heart problems, and other illnesses that have nothing to do with cancer.
Almost every part of the body is made of cells. Normally, these cells grow and divide to make more cells. When the old cells are used up or damaged, they die and are replaced by new ones. But in cancer, the cells become abnormal and grow and multiply out of control. The cells can also break away from the original tumor and travel to other parts of the body. There they continue to grow and may form more tumors.
Cancer can start in any type of cell in the body. But there are some types of cells that are more likely to become cancerous than others. For example, cancer often starts in blood vessels or glands. It is less common for cancer to start in bones or muscles.
Researchers are learning more about how cancer develops and spreads. They are studying the genetic changes (mutations) that cause cancer and how these mutations change normal cells into cancer cells. They are also studying how the environment around cells influences whether they become cancerous or not.
Early scientists noticed that some cells in the human body grew and multiplied out of control. They also noticed that these cells tended to spread from one part of the body to other parts. Scientists at this time called these growing tissue masses a tumor.
The first step in the development of a cancer is for an abnormal gene to change. This is what we call a driver mutation. The change in the gene triggers an abnormal increase in a cell’s rate of proliferation.
Normal cells are regulated by homeostatic (or ecological) controls, which limit their proliferation rate and allow them to differentiate into specific tissues and organs. Changes in genes that increase the growth rate of cancer cells can override these homeostatic constraints.
Unlike normal cells, cancer cells do not die when they are damaged or overloaded with nutrients. Instead, they ignore the signals that normally tell cells to stop dividing or to die (a process called programmed cell death or apoptosis). They can also invade nearby tissues and travel to other parts of the body. They can also ignore the signals that normally tell cells to move around and that tell blood vessels to grow toward them.
In addition, cancer cells often use different ways to get energy from nutrients and can reproduce more quickly than normal cells. Because of this, they can sometimes out-compete healthy cells for resources and crowd out vital cells in a tissue. They can also trick the immune system into helping them stay alive and spreading.
A tumor is a mass of cancer cells that grows in the body and spreads to other parts of the body. The cells in a cancer are abnormal and grow out of control. When cancer spreads to a different part of the body, it is called metastasis. Cancer is a complex disease and can cause many different symptoms. It can affect any part of the body. Most people who have cancer have other health problems, too. These include infections, heart problems, and other illnesses that have nothing to do with cancer. Almost every part of the body is made of cells. Normally, these cells grow and divide to make more cells. When the old cells are used up or damaged, they die and are replaced by new ones. But in cancer, the cells become abnormal and grow and multiply out of control. The cells can also break away from the original tumor and travel to other parts of the body. There they continue to grow and may form more tumors. Cancer can start in any type of cell in the body. But there are some types of cells that are more likely to become cancerous than others. For example, cancer often starts in blood vessels or glands. It is less common for cancer to start in bones or muscles. Researchers are learning more about how cancer develops and spreads. They are studying the genetic changes (mutations) that cause cancer and how these mutations change normal cells into cancer cells. They are also studying how the environment around cells influences whether they become cancerous or not. Early scientists noticed that some cells in the human body grew and multiplied out of control. They also noticed that these cells tended to spread from one part of the body to other parts. Scientists at this time called these growing tissue masses a tumor. The first step in the development of a cancer is for an abnormal gene to change. This is what we call a driver mutation. The change in the gene triggers an abnormal increase in a cell’s rate of proliferation. Normal cells are regulated by homeostatic (or ecological) controls, which limit their proliferation rate and allow them to differentiate into specific tissues and organs. Changes in genes that increase the growth rate of cancer cells can override these homeostatic constraints. Unlike normal cells, cancer cells do not die when they are damaged or overloaded with nutrients. Instead, they ignore the signals that normally tell cells to stop dividing or to die (a process called programmed cell death or apoptosis). They can also invade nearby tissues and travel to other parts of the body. They can also ignore the signals that normally tell cells to move around and that tell blood vessels to grow toward them. In addition, cancer cells often use different ways to get energy from nutrients and can reproduce more quickly than normal cells. Because of this, they can sometimes out-compete healthy cells for resources and crowd out vital cells in a tissue. They can also trick the immune system into helping them stay alive and spreading.