What is Cancer?

It’s a disease in which some cells grow uncontrollably and can spread to other parts of the body. It can start almost anywhere in the body. There are more than 100 types of cancer, and they are usually named for the organs or tissues where they originate (such as lung or colon cancer).

Our cells naturally grow and multiply to form new cells as the body needs them. When the cells get old or damaged, they die off and new cells step in. Cancer cells act abnormally. They can ignore the signals your body sends them telling them to stop or die off. They can invade other parts of the body where normal cells don’t go. They can take in nutrients in ways normal cells won’t. They can even hide from or trick the immune system.

As cancer cells multiply, they can form tumors, which are lumps of tissue that can be cancerous (malignant) or not cancerous (benign). Cancer cells can encourage blood vessels to form near tumors to help it grow. They can also trick the immune system into protecting a tumor rather than attacking it.

While benign tumors do not spread into nearby tissues, they can grow quite large and lead to life-threatening symptoms. Cancerous tumors can spread into nearby tissue and form new tumors in other parts of the body.

Cancer is a genetic disease, in that it is caused by changes to our genes that control how cells function and how they grow and divide. Those changes can happen because:

There’s an error that happens as cells divide
Harmful substances in the environment, such as tobacco smoke or ultraviolet rays from the sun, cause damage to DNA
They were inherited from our parents

As we age, the risk of cancer rises, mainly because our body loses the ability to eliminate cells with damaged DNA before they turn cancerous. Once a cancer has spread to other parts of the body, most treatment options are used to control the continued growth of the cancer or relieve its symptoms to prolong the life of the patient.

Cancers are further categorized by specific types of cells where they form. Some of them include:

Carcinoma, forms in the cells that cover the inside and outside surfaces of the body, such as the lining of organs. This includes skin, breast, colon and kidney cancers, among others.
Sarcoma, forms in bone and soft tissues, including muscle, fat, blood vessels, lymph vessels, and fibrous tissue (such as tendons and ligaments). Osteosarcoma is the most common cancer of the bones.
Leukemia, begins in the blood-forming tissue of the bone marrow. Unlike other types of cancer, leukemia does not form a tumor, but instead leads to abnormal white blood cells building up in the blood and bone marrow, crowding out normal blood cells.
Lymphoma, begins in lymphocytes (T cells or B cells), the disease-fighting white blood cells of the immune system. The two main types are Hodgkin lymphoma and Non-Hodgkins lymphoma.
Multiple Myeloma, forms in plasma cells and leads to tumors in bones throughout the body. This type of cancer is also called plasma cell myeloma and Kahler disease.
Melanoma, begins in cells that make melanin (the pigment that gives skin its color). Most melanomas form on the skin surface, but can also form in other pigmented tissues, such as the eye.
Brain and spinal cord tumors, are named based on the type of cell in which they formed and where the tumor first formed in the central nervous system. Brain tumors can be benign or malignant.