Why are carcinomas the most
It is present in the skin, as well as the covering and lining of organs and internal passageways, such as the gastrointestinal tract.
Carcinomas are divided into two major subtypes: adenocarcinoma , which develops in an organ or gland , and squamous cell carcinoma , which originates in the squamous epithelium. Adenocarcinomas generally occur in mucus membranes and are first seen as a thickened plaque -like white mucosa. They often spread easily through the soft tissue where they occur. Squamous cell carcinomas occur in many areas of the body.
Most carcinomas affect organs or glands capable of secretion, such as the breasts, which produce milk, or the lungs, which secrete mucus, or colon or prostate or bladder. Sarcoma refers to cancer that originates in supportive and connective tissues such as bones, tendons, cartilage , muscle , and fat. In some cases, children who have been exposed to these agents may develop a second malignancy later in life.
A second malignancy is a cancer that appears as a result from treatment of a different cancer. Cancer Genes How do genes affect cancer growth?
Types of cancer genes There are three main types of genes that can affect cell growth and are altered mutated in certain types of cancers, including the following: Oncogenes : These genes regulate the normal growth of cells. Scientists commonly describe oncogenes as similar to a cancer "switch" that most people have in their bodies.
What "flips the switch" to make these oncogenes suddenly become unable to control the normal growth of cells and allowing abnormal cancer cells to begin to grow, is unknown. Tumor suppressor genes : These genes are able to recognize abnormal growth and reproduction of damaged cells, or cancer cells, and can interrupt their reproduction until the defect is corrected.
If the tumor suppressor genes are mutated, however, and they do not function properly, tumor growth may occur. Mismatch-repair genes : These genes help recognize errors when DNA is copied to make a new cell. If the DNA does not "match" perfectly, these genes repair the mismatch and correct the error.
If these genes are not working properly, however, errors in DNA can be transmitted to new cells, causing them to be damaged. Previous Section Next Section. Condition Spotlight. Sugar and Health - the Sweet, the Sour, and the Sticky! Play Video How Can I Care for Myself? Clinical Trials Clinical trials are research studies that evaluate a new medical approach, device, drug, or other treatment. Open Trials Closed Trials. Clinical Trials View All ».
Clinical Trials. MyHealth Login. Financial Assistance. Medical Records. Contact Us. Germ cell tumors are a type of tumor that begins in the cells that give rise to sperm or eggs. These tumors can occur almost anywhere in the body and can be either benign or malignant. Neuroendocrine tumors form from cells that release hormones into the blood in response to a signal from the nervous system. These tumors, which may make higher-than-normal amounts of hormones, can cause many different symptoms.
Neuroendocrine tumors may be benign or malignant. Our definition of neuroendocrine tumors has more information. Carcinoid tumors are a type of neuroendocrine tumor. They are slow-growing tumors that are usually found in the gastrointestinal system most often in the rectum and small intestine.
Carcinoid tumors may spread to the liver or other sites in the body, and they may secrete substances such as serotonin or prostaglandins, causing carcinoid syndrome. Our page on gastrointestinal carcinoid tumors has more information. Menu Contact Dictionary Search.
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Some types of cancer run in certain families, but most cancers are not clearly linked to the genes we inherit from our parents.
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