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Cancer is a set of diseases in which a group of cells show uncontrolled growth, attack that intrudes upon and destroys adjacent tissues, and sometimes metastasis, or

Cancer and its types

spreading to other locations in the body through lymph or blood. These three malignant properties of cancers distinguish them from benign tumors, which do not invade or metastasize. The causes of cancer are divided into two groups- environmental cause and hereditary genetic cause. Cancer is first and foremost an environmental disease, though genetics influence the risk of some cancers.

Cancers are categorized by the form of cell that the tumor resembles and is therefore presumed to be the source of the tumor. These types include:

Carcinoma: Cancer resulting from epithelial cells. This group includes many of the most common cancers, including those of the prostate, breast, lung and colon.

Sarcoma: Cancer resulting from connecti

ve tissue, or mesenchymal cells.

Lymphoma and leukemia: Cancer resulting from hematopoietic cells

Germ cell tumor: Cancer resulting from pluripotent cells. In adults these are most often found in the testicle and ovary, but are more common in babies and young children.

Blastoma: Cancer resulting from immature “precursor” or embryonic tissue. These are also commonest in kids.

Cancers are generally named using -carcinoma, -sarc

oma or -blastoma as a suffix, with the Latin or Greek word for the organ or tissue of origin as the source. For instance, a cancer of the liver is called hepatocarcinoma; a cancer of fat cells is called a liposarcoma. For some general cancers, the English organ name is used. For instance, the most common type of breast cancer is called ductal carcinoma of the breast.

Symptoms of cancer

Local symptoms: are limited to the site of the primary cancer. They can comprise lumps or swelling, hemorrhage, ulceration and pain. Even though local pain commonly occurs in advanced cancer, the primary swelling is often painless.

Metastatic symptoms: are due to the spread of cancer to other locations in the body. They can include enlarged lymph nodes, hepatomegaly or splenomegaly which can be felt in theabdomen, pain or crack of affected bones, and neurological symptoms.

Mystemic symptoms: occur due to remote effects of the cancer that are not related to direct or metastatic spread. Some of these effects can comprise weight loss, fatigue, excessive sweating, anemia and other specific conditions termed paraneoplastic phenomena. These may be mediated byimmunological or hormonal signals from the cancer cells.

Causes of Cancer

Cancers are primarily an environmental disease with 90-95% of cases attributed to environmental factors and 5-10% due to genetics. Environmental, as used by cancer researchers, means any cause that is not genetic.

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