Cancer is the uncontrolled growth of abnormal cells anywhere in a body. These abnormal cells are termed cancer cells, malignant cells, or tumour cells. These cells can infiltrate normal body tissues. Many cancers and the abnormal cells that compose the cancer tissue are further identified by the name of the tissue that the abnormal cells originated from (for example, breast cancer, lung cancer, colorectal cancer). Cancer is not confined to humans; animals and other living organisms can get cancer. Below is a schematic that shows normal cell division and how when a cell is damaged or altered without repair to its system, the cell usually dies. Also shown is what occurs when such damaged or unrepaired cells do not die and become cancer cells and show uncontrolled division and growth -- a mass of cancer cells develop. Frequently, cancer cells can break away from this original mass of cells, travel through the blood and lymph systems, and lodge in other organs where they can again repeat the uncontrolled growth cycle. This process of cancer cells leaving an area and growing in another body area is termed metastatic spread or metastasis. For example, if breast cancer cells spread to a bone, it means that the individual has metastatic breast cancer to bone. This is not the same as "bone cancer," which would mean the cancer had started in the bone.
Types
There are many types of cancer. A few common types of cancer include,
Bladder Cancer
Bladder cancer occurs in the tissues of the bladder, which is the organ in the body that holds urine. here are three types of bladder cancer:
Transitional cell carcinoma
Squamous cell carcinoma
Adenocarcinoma
Breast Cancer
Breast cancer is cancer that develops in breast cells. Typically, the cancer forms in either the lobules or the ducts of the breast. Lobules are the glands that produce milk, and ducts are the pathways that bring the milk from the glands to the nipple. Cancer can also occur in the fatty tissue or the fibrous connective tissue within your breast.
The uncontrolled cancer cells often invade other healthy breast tissue and can travel to the lymph nodes under the arms. The lymph nodes are a primary pathway that help the cancer cells move to other parts of the body
Colon and Rectal Cancer
Colorectal cancer is a cancer that starts in the colon or the rectum. These cancers can also be named colon cancer or rectal cancer, depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common.
Endometrial Cancer
Endometrial cancer is a cancer that arises from the endometrium (the lining of the uterus or womb). It is the result of the abnormal growth of cells that have the ability to invade or spread to other parts of the body. The first sign is most often vaginal bleeding not associated with a menstrual period.
Kidney Cancer
Kidney cancer is a disease that starts in the kidneys. It happens when healthy cells in one or both kidneys grow out of control and form a lump (called a tumor). Renal cell carcinoma is the most common type of kidney cancer in adults.
Leukaemia
Leukaemia is a cancer which starts in blood-forming tissue, usually the bone marrow. It leads to the over-production of abnormal white blood cells, the part of the immune system which defends the body against infection.
Liver Cancer
Liver cancer is cancer that occurs in the liver. The liver is the largest glandular organ in the body and performs various critical functions to keep the body free of toxins and harmful substances. It’s located in the right upper quadrant of the abdomen, right below the ribs. The liver is responsible for producing bile, which is a substance that helps you digest fats, vitamins, and other nutrients. This vital organ also stores nutrients such as glucose, so that you remain nourished at times when you’re not eating. It also breaks down medications and toxins. When cancer develops in the liver, it destroys liver cells and interferes with the ability of the liver to function normally.
Lung Cancer
Lung cancer is a type of cancer that begins in the lungs. Your lungs are two spongy organs in your chest that take in oxygen when you inhale and release carbon dioxide when you exhale. Lung cancer is the leading cause of cancer deaths worldwide. People who smoke have the greatest risk of lung cancer, though lung cancer can also occur in people who have never smoked.
Melanoma
Melanoma, also known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin but may rarely occur in the mouth, intestines or eye (uveal melanoma).
Non-Hodgkin Lymphoma
Non-Hodgkin lymphoma (NHL) is a group of blood cancers that includes all types of lymphoma except Hodgkin lymphomas. Symptoms include enlarged lymph nodes, fever, night sweats, weight loss and tiredness. Other symptoms may include bone pain, chest pain or itchiness.
Pancreatic Cancer
Pancreatic cancer is cancer that forms in the cells of the pancreas. Pancreatic cancer begins in the tissues of your pancreas — an organ in your abdomen that lies behind the lower part of your stomach. Your pancreas releases enzymes that aid digestion and produces hormones that help manage your blood sugar.
Prostate Cancer
Prostate cancer is a form of cancer that develops in the prostate gland. It is the second-leading cause of cancer deaths for men in the U.S. About 1 in 9 men will be diagnosed with prostate cancer in their lifetime. This year, nearly 191,000 men will be diagnosed with prostate cancer.
Thyroid Cancer
Thyroid cancer occurs in the cells of the thyroid — a butterfly-shaped gland located at the base of your neck, just below your Adam's apple. Your thyroid produces hormones that regulate your heart rate, blood pressure, body temperature and weight. Thyroid cancer might not cause any symptoms at first.
