Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start -- for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.
Cancer types can be grouped into broader categories. The main categories of cancer include:
Carcinoma - cancer that begins in the skin or in tissues that line or cover internal organs.
Sarcoma - cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.
Leukemia - cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.
Lymphoma and myeloma - cancers that begin in the cells of the immune system.
Central nervous system cancers - cancers that begin in the tissues of the brain and spinal cord.
All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells become cancer cells. The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.
However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.
Not all tumors are cancerous; tumors can be benign or malignant. Benign tumors aren't cancerous. They can often be removed, and, in most cases, they do not come back. Cells in benign tumors do not spread to other parts of the body.Malignant tumors are cancerous. Cells in these tumors can invade nearby tissues and spread to other parts of the body. The spread of cancer from one part of the body to another is called metastasis. Some cancers do not form tumors. For example, leukemia is a cancer of the bone marrow and blood.
Taking a daily multivitamin pill may lower the risk of developing cancer in men, US researchers have claimed.Their study followed nearly 15,000 men, aged over 50, for more than a decade. The findings, published in the Journal of the American Medical Association, reported a small reduction in cancer cases in men taking vitamin pills. But experts warned that other studies had found the opposite effect and that eating a diet packed with fruit and vegetables was a safer bet.
Death rates from cancer are "set to fall dramatically" by 2030, according to Cancer Research UK. It says fewer people smoking as well as improvements in diagnosis and treatment will lead to a 17% drop in death rate. About 170 UK deaths per 100,000 of population were from cancer in 2010, and this figure is predicted to fall to 142 out of every 100,000.
A Shropshire schoolgirl, who contracted a rare form of cancer, has been fitted with a metal leg bone which will "grow with her" as she gets older. Hannah Baker, 9, from Clee St Margaret, had the femur in her left leg removed after she was diagnosed with an osteosarcoma tumour in April. Surgeons at the Royal Orthopaedic Hospital in Birmingham, have replaced it with a special titanium rod which is extended by using electromagnetic pulses.
Diabetes is classified into two types. In Type 1 diabetes, formerly called insulin-dependent diabetes mellitus (IDDM) and juvenile-onset diabetes, the body does not produce insulin or produces it only in very small quantities. Symptoms usually appear suddenly, typically in individuals under 20 years of age. Most cases occur around puberty—around age 10 to 12 in girls and age 12 to 14 in boys. In the United States Type 1 diabetes accounts for 5 to 10 percent of all diabetes cases.
Known as shingles, this is a one-time recurrence of the symptoms of chicken pox, usually during adulthood. It is caused by the chicken pox virus attacking a sensory nerve. The skin over the nerve generally breaks out in blisters a few days after the onset of the disorder, which is accompanied by pain and frequent numbness or hypersensitivity along the course of the nerve, usually the trunk. The blisters are at first clear, but become cloudy within a few days and form crusts that dry up after five or ten days.
Infectious Mononucleosis, also glandular fever, an acute disease of humans, caused by the Epstein-Barr virus. Its mode of transmission is not known, but may be facilitated by saliva exchange, as in kissing. The disease, which attacks chiefly adolescents and young adults, usually runs its course in two to four weeks, although cases may be as brief as a week or last six to eight weeks. After recovery, weakness may continue for several months.
Chicken Pox, also called varicella, contagious viral disease that affects mainly children. According to the Centers for Disease Control and Prevention (CDC), more than 4 million people develop chicken pox each year, and more than 95 percent of Americans will have had chicken pox by the time they reach adulthood. There are about 100 deaths from chicken pox each year in the United States.
Two types of herpes simplex are known. The first causes cold sores or fever blisters—an eruption of blisters that often occurs during the course of or after one of a variety of diseases associated with fever. The blisters usually appear around the mouth and on the lips (herpes labialis); about the nose, face, and ears; and in the mouth and pharynx.