Cancer Starts When Genetic Changes Tip the Balance Toward Excessive Cell Growth
Cancer is a disease that starts when abnormal cells start growing out of control and forming tumors. The cells may also break away from the tumor and travel to other parts of the body, where they continue to grow and form more tumors.
Normally, the number of cells in the body is carefully controlled so that new cells are made to replace old ones and to grow and develop as needed. Cancer begins when genetic changes tip the balance toward excessive cell growth and development.
The first signs of cancer may be similar to symptoms of many other conditions, such as the flu or a common infection. For this reason, it is important to talk to your doctor about any new or unusual symptoms. The earlier cancer is found, the easier it is to treat.
When doctors discovered that living tissues are composed of cells and that all cells are direct descendants of previous cells, they began to ask how and why abnormal cells arise. They wondered what kinds of cells cancers begin in, how they differ from normal cells and what events promote their growth and spread.
With the help of the microscope, doctors observed that cancer cells look different than healthy cells and could be distinguished by their size, shape, color and other properties. They were able to grow some of these cells in laboratory tests and showed that they are capable of forming tumors. They also found that cancer cells can break down the tissues they invade and can produce substances that attract blood vessels to the tumor and help it grow.
Cancer cells are also characterized by the fact that they have more DNA than healthy cells and that their DNA contains mutations (abnormal changes). Mutations can cause normal cells to lose control of the way they grow and develop. The mutations that cause cancer also change the ways that genes express themselves. These changes disrupt the normal functions of cells and the way the body makes proteins, which carry out the instructions in our cells.
The body normally safeguards against cancer through a process called apoptosis, which causes abnormal cells to die or to be reabsorbed into the body. In addition, the body has other methods for protecting itself, such as helper molecules that repair damaged DNA or that cause precancerous cells to die. But in cancer cells, the DNA damage isn’t repaired or the abnormal cells don’t die. As a result, the cancer cells keep dividing and growing, producing more and more abnormal cells with defective DNA. The abnormal cells also rob the body of nutrients and oxygen as they grow and spread.
Cancer is a disease that starts when abnormal cells start growing out of control and forming tumors. The cells may also break away from the tumor and travel to other parts of the body, where they continue to grow and form more tumors. Normally, the number of cells in the body is carefully controlled so that new cells are made to replace old ones and to grow and develop as needed. Cancer begins when genetic changes tip the balance toward excessive cell growth and development. The first signs of cancer may be similar to symptoms of many other conditions, such as the flu or a common infection. For this reason, it is important to talk to your doctor about any new or unusual symptoms. The earlier cancer is found, the easier it is to treat. When doctors discovered that living tissues are composed of cells and that all cells are direct descendants of previous cells, they began to ask how and why abnormal cells arise. They wondered what kinds of cells cancers begin in, how they differ from normal cells and what events promote their growth and spread. With the help of the microscope, doctors observed that cancer cells look different than healthy cells and could be distinguished by their size, shape, color and other properties. They were able to grow some of these cells in laboratory tests and showed that they are capable of forming tumors. They also found that cancer cells can break down the tissues they invade and can produce substances that attract blood vessels to the tumor and help it grow. Cancer cells are also characterized by the fact that they have more DNA than healthy cells and that their DNA contains mutations (abnormal changes). Mutations can cause normal cells to lose control of the way they grow and develop. The mutations that cause cancer also change the ways that genes express themselves. These changes disrupt the normal functions of cells and the way the body makes proteins, which carry out the instructions in our cells. The body normally safeguards against cancer through a process called apoptosis, which causes abnormal cells to die or to be reabsorbed into the body. In addition, the body has other methods for protecting itself, such as helper molecules that repair damaged DNA or that cause precancerous cells to die. But in cancer cells, the DNA damage isn’t repaired or the abnormal cells don’t die. As a result, the cancer cells keep dividing and growing, producing more and more abnormal cells with defective DNA. The abnormal cells also rob the body of nutrients and oxygen as they grow and spread.