What is Cancer?
Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. It starts almost anywhere in the trillions of cells that make up the human body. Normally, the body’s cells grow and multiply to replace old or damaged cells. But sometimes this process goes wrong. Instead of growing and dividing, some cells start to grow out of control and form lumps of tissue called tumors. Some of these tumors are cancerous, but others are not.
The exact cause of cancer is not known. But some risk factors, such as smoking or too much sun exposure, can increase the chance of getting it. Cancer can also happen because of genes that are inherited from your parents. These genes may make certain cell structures more likely to develop cancer.
There are several different kinds of cancer, and each type of cancer is treated differently. Some types are more common than others, and some are more dangerous. Cancers can be described as localized (only in the part of the body where they started), regional (has spread to nearby lymph nodes or organs), or distant (has spread to other parts of the body). The stage of a cancer determines how much treatment you need.
Most doctors agree that cancer is a complex phenomenon, and many different things can lead to it. But there is a general understanding that cancers often start when a single cell gets a mutation that causes it to grow and divide without control. This happens when a mutation changes the instructions that the cell uses to tell itself whether to grow or die.
In normal multicellular organisms, the cells are regulated by standard ecological limits on growth that are based on how densely packed the cells are. This allows the cells to stay alive and divide as long as the nutrients they need to survive are available. But in cancer, the mutated cells keep on dividing even when the cells get packed very tightly (a process called density-dependent inhibition).
Once the mutated cancer cells become very large, they lose this ability to stop growing and begin to multiply at an ever-increasing rate. As they do so, they produce more and more mutations, and these mutations change how the cell functions.
Cancers can then spread to other parts of the body through blood vessels or by breaking away from the original location of the tumor and travelling to other tissues. Once they are in other parts of the body, they can cause new tumors and more symptoms.
The most common types of cancer are lung, breast, and colon cancer. But there are more than 200 different types of cancer, and many people with cancer get sick in other ways. For example, some get infections or have heart problems that don’t relate to their cancer. These other problems are called recurrences. They usually happen because of a combination of environmental and genetic factors.
Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. It starts almost anywhere in the trillions of cells that make up the human body. Normally, the body’s cells grow and multiply to replace old or damaged cells. But sometimes this process goes wrong. Instead of growing and dividing, some cells start to grow out of control and form lumps of tissue called tumors. Some of these tumors are cancerous, but others are not. The exact cause of cancer is not known. But some risk factors, such as smoking or too much sun exposure, can increase the chance of getting it. Cancer can also happen because of genes that are inherited from your parents. These genes may make certain cell structures more likely to develop cancer. There are several different kinds of cancer, and each type of cancer is treated differently. Some types are more common than others, and some are more dangerous. Cancers can be described as localized (only in the part of the body where they started), regional (has spread to nearby lymph nodes or organs), or distant (has spread to other parts of the body). The stage of a cancer determines how much treatment you need. Most doctors agree that cancer is a complex phenomenon, and many different things can lead to it. But there is a general understanding that cancers often start when a single cell gets a mutation that causes it to grow and divide without control. This happens when a mutation changes the instructions that the cell uses to tell itself whether to grow or die. In normal multicellular organisms, the cells are regulated by standard ecological limits on growth that are based on how densely packed the cells are. This allows the cells to stay alive and divide as long as the nutrients they need to survive are available. But in cancer, the mutated cells keep on dividing even when the cells get packed very tightly (a process called density-dependent inhibition). Once the mutated cancer cells become very large, they lose this ability to stop growing and begin to multiply at an ever-increasing rate. As they do so, they produce more and more mutations, and these mutations change how the cell functions. Cancers can then spread to other parts of the body through blood vessels or by breaking away from the original location of the tumor and travelling to other tissues. Once they are in other parts of the body, they can cause new tumors and more symptoms. The most common types of cancer are lung, breast, and colon cancer. But there are more than 200 different types of cancer, and many people with cancer get sick in other ways. For example, some get infections or have heart problems that don’t relate to their cancer. These other problems are called recurrences. They usually happen because of a combination of environmental and genetic factors.