Page 33 Complete Your CE Test Online - Click Here and other objects. The magnetic energy emitted by power lines is a low-frequency form of radiation that does not ionize molecules or damage DNA [158]. “Antiperspirants or deodorants cause breast cancer” The best studies so far have found no evidence linking the chemicals typically found in antiperspirants and deodorants with changes in breast tissue [158]. Many people also believe that “toxins” are released through sweat, and that these can build up when a person uses antiperspirant. There is no biological basis for this, since sweat consists of fluids and electrolytes, and does not secrete “toxic” substances. “Dying your hair causes cancer” There is no convincing scientific evidence that personal hair dye use increases the risk of cancer. Some studies suggest, however, that hairdressers and barbers who are regularly exposed to large quantities of hair dye and other chemical products may have an increased risk of bladder cancer [158]. TYPES OF CANCER Cancers are typically named for the organs or tissues where the cancers form. For example, lung cancer starts in cells of the lung, and brain cancer starts in cells of the brain. Cancers also may be described by the type of cell that formed them, such as an epithelial cell or a squamous cell [202]. Cell-specific types of cancer These are the most common types of cancer by cell type. This is the terminology that is found on pathology reports and can be used to help patients understand these reports. Carcinoma Carcinomas are the most common type of cancer. They are formed by epithelial cells, which cover the inside and outside surfaces of the body. Epithelial cells often have a column-like shape when viewed under a microscope, but there are many types of epithelial cells. Carcinomas that begin in different epithelial cell types have even more-specific names: ● ● Adenocarcinoma is a cancer that forms in glandular epithelial cells, which produce fluids or mucus. Most cancers of the breast, colon, and prostate are adenocarcinomas. ● ● Basal cell carcinoma is a cancer that begins in the lower or basal layer of the epidermis. ● ● Squamous cell carcinoma is a cancer that forms in squamous cells, epithelial cells that lie just beneath the outer surface of the skin. Squamous cells are also found in organs like the stomach, intestines, lungs, bladder, and kidneys. Squamous cells look flat, like fish scales, when viewed under a microscope. Squamous cell carcinomas may also be called epidermoid carcinomas. ● ● Transitional cell carcinoma is a cancer that forms in a type of epithelial tissue called transitional epithelium, or urothelium. This tissue, which is made up of many layers of epithelial cells that can get bigger and smaller, is found in the linings of the bladder, ureters, the renal pelvis, and a few other organs. Some cancers of the bladder, ureters, and kidneys are transitional cell carcinomas [202]. Sarcoma Sarcomas are cancers that form in bone and soft tissues, including muscle, fat, blood vessels, lymph vessels, and fibrous tissue such as tendons and ligaments. Soft tissue sarcoma forms in soft tissues of the body, including muscle, tendons, fat, blood vessels, lymph vessels, nerves, fibrous tissues such as tendons and ligaments, and the tissue around joints. The most common types of soft tissue sarcoma are leiomyosarcoma, Kaposi’s sarcoma, malignant fibrous histiocytoma, liposarcoma, and dermatofibrosarcoma protuberans. Osteosarcoma is the most common cancer of bone [202]. Leukemia Cancers that begin in the blood-forming tissue of the bone marrow are called leukemias. Large numbers of abnormal white blood cells (leukemia cells and leukemic blast cells) proliferate in the blood and bone marrow, crowding out normal blood cells. Low numbers of normal blood cells can result in anemia, thrombocytopenia, and leukopenia, which can cause fatigue, hypoxia, abnormal bleeding, and an increased risk of infection. There are four common types of leukemia, which are grouped based on how the speed of disease progression (acute or chronic) and on the type of hematopoietic cell the cancer starts in (i.e. lymphoblastic or myeloid) [202]. Lymphoma Lymphoma is cancer that begins in T lymphocytes or B lymphocytes (commonly called T cells and B cells). These white blood cells normally help fight infection and are part of the immune system. In lymphoma, abnormal lymphocytes build up in lymph nodes, lymph vessels, and other organs of the body. There are two main types of lymphoma [202]: ● ● Hodgkin’s lymphoma: People with this disease have abnormal lymphocytes that are called Reed-Sternberg cells. These lymphocytes usually originate from B cells. ● ● Non-Hodgkin lymphoma: This is a large group of cancers that start in lymphocytes. The cancers can grow quickly or slowly and can originate from B cells or T cells. Multiple myeloma Multiple myeloma begins in plasma cells, another type of immune cell. The abnormal plasma cells, called myeloma cells, crowd the bone marrow and form tumors in bones all through the body. Multiple myeloma is also called plasma cell myeloma and Kahler disease. Melanoma Melanoma is cancer that begins in cells that become melanocytes, which are specialized cells that make melanin (the pigment that gives skin its color). Most melanomas form on the skin, but melanomas can also form in other pigmented tissues, such as the eye [202]. They can also form under the nails and more rarely, on mucous membranes such as the mouth or genital and perianal areas [33]. Brain and spinal cord tumors There are different types of brain and spinal cord tumors. These tumors are named based on the type of cell in which they formed and where the tumor first formed in the central nervous system. For example, an astrocytic tumor begins in star-shaped brain cells called astrocytes, which help keep nerve cells healthy. Brain tumors can be benign or malignant, but any that continue to grow can be life-threatening [202]. Less common cellular-based cancer types ● ● Germ cell tumors: Germ cell tumors begin in the cells that normally give rise to sperm or eggs in the testes or ovaries. These tumors can occur almost anywhere in the body (because germ cells can develop in other parts of the body), although extragonadal germ cell tumors happen most often in the pineal gland, mediastinum, or retroperitoneum. They can be either benign teratomas or malignant (seminomas and nonseminomas) [162]. ● ● Neuroendocrine tumors: Neuroendocrine tumors arise from cells that release hormones into the blood in response to a signal from the nervous system. These tumors, which may make higher-than-