What is Cancer

Cancer (medical term: malignant neoplasm)is a class of diseases in which a group of cells display the traits of uncontrolled growth (growth and division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties differentiate them from benign tumors, which are self-limited, do not invade or metastasize. Most form a tumor but some, like leukemia, do not.

It may affect people at all ages, even fetuses, but risk for the more common varieties tends to increase with age. It causes about 13% of all deaths. According to the American Society, 7.6 million people died from it in the world during 2007.

Abnormalities in the Genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. Complex interactions between carcinogens and the host genome may explain why only some develop it after exposure to a known carcinogen. Genetics such as DNA methylation, and microRNAs are increasingly being recognized as important.

Genetic abnormalities typically affect two general classes of genes.It promotes Oncogenes are often activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are often inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.

It is usually classified according to the tissue from which the cancerous cells originate, the primary tumor, as well as the normal cell type they most resemble. These are location and histology, respectively. A definitive diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. Mostly can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed it is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of it. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of the patients is most influenced by the type, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.

Go Back from Cancer to Ovarian Cancer