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Infectious Causes Of Cancer
Estimates place the worldwide risk of cancers from infectious causes at 16.1%. Viral infections are risk factors for cervical cancer, 80% of liver cancers, and 15–20% of the other cancers. This proportion varies in different regions of the world from a high of 32.7% in Sub-Saharan Africa to 3.3% in Australia and New Zealand. ''Helicobacter pylori'' is associated with stomach cancer, and ''Mycobacterium'', some other bacteria and parasites also have an effect. A virus that can cause cancer is called an ''oncovirus'' or ''tumor virus''. These include the human papillomavirus, which is associated with cervical carcinoma and nasopharyngeal carcinoma; Epstein-Barr virus, which is associated with a variety of Epstein-Barr virus associated lymphoproliferative lymphomas; Kaposi's sarcoma herpesvirus, which is associated with Kaposi's sarcoma and primary effusion lymphoma; hepatitis B and hepatitis C viruses which are associated with hepatocellular carcinoma; human T-cell leukemia vir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatitis C
Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, abdominal pain, and yellow tinged skin occurs. The virus persists in the liver in about 75% to 85% of those initially infected. Early on, chronic infection typically has no symptoms. Over many years however, it often leads to liver disease and occasionally cirrhosis. In some cases, those with cirrhosis will develop serious complications such as liver failure, liver cancer, or dilated blood vessels in the esophagus and stomach. HCV is spread primarily by blood-to-blood contact associated with injection drug use, poorly sterilized medical equipment, needlestick injuries in healthcare, and transfusions. Using blood screening, the risk from a transfusion is less than one per two million. It may also be spread from an infected mother to her ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cancer Prevention
Cancer prevention is the practice of taking active measures to decrease the incidence of cancer and mortality. The practice of prevention is dependent upon both individual efforts to improve lifestyle and seek preventive screening, and socioeconomic or public policy related to cancer prevention. Globalized cancer prevention is regarded as a critical objective due to its applicability to large populations, reducing long term effects of cancer by promoting proactive health practices and behaviors, and its perceived cost-effectiveness and viability for all socioeconomic classes. The majority of cancer cases are due to the accumulation of environmental pollution being inherited as epigenetic damage and many, but not all, of these environmental factors are controllable lifestyle choices. Greater than a reported 75% of cancer deaths could be prevented by avoiding risk factors including: tobacco, overweight / obesity, an insufficient diet, physical inactivity, alcohol, sexually transmitte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cholangiocarcinoma
Cholangiocarcinoma, also known as bile duct cancer, is a type of cancer that forms in the bile ducts. Symptoms of cholangiocarcinoma may include abdominal pain, yellowish skin, weight loss, generalized itching, and fever. Light colored stool or dark urine may also occur. Other biliary tract cancers include gallbladder cancer and cancer of the ampulla of Vater. Risk factors for cholangiocarcinoma include primary sclerosing cholangitis (an inflammatory disease of the bile ducts), ulcerative colitis, cirrhosis, hepatitis C, hepatitis B, infection with certain liver flukes, and some congenital liver malformations. However, most people have no identifiable risk factors. The diagnosis is suspected based on a combination of blood tests, medical imaging, endoscopy, and sometimes surgical exploration. The disease is confirmed by examination of cells from the tumor under a microscope. It is typically an adenocarcinoma (a cancer that forms glands or secretes mucin). Cholangioca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clonorchis Sinensis
''Clonorchis sinensis'', the Chinese liver fluke, is a liver fluke belonging to the class Trematoda, phylum Platyhelminthes. It infects fish-eating mammals, including humans. In humans, it infects the common bile duct and gall bladder, feeding on bile. It was discovered by British physician James McConnell at the Medical College Hospital in Calcutta (Kolkata) in 1874. The first description was given by Thomas Spencer Cobbold, who named it ''Distoma sinense''. The fluke passes its lifecycle in three different hosts, namely freshwater snail as first intermediate hosts, freshwater fish as second intermediate host, and mammals as definitive hosts. Endemic to Asia and Russia, ''C. sinensis'' is the most prevalent human fluke in Asia and third-most in the world. It is still actively transmitted in Korea, China, Vietnam, and Russia. Most infections (about 85%) occur in China. The infection, called clonorchiasis, generally appears as jaundice, indigestion, biliary inflammation, bile duct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opisthorchis Viverrini
''Opisthorchis viverrini'', common name Southeast Asian liver fluke, is a food-borne trematode parasite from the family Opisthorchiidae that infects the bile duct. People are infected after eating raw or undercooked fish. Infection with the parasite is called opisthorchiasis. ''O. viverrini'' infection also increases the risk of cholangiocarcinoma, a cancer of the bile ducts. A small, leaf-like fluke, ''O. viverrini'' completes its lifecycle in three different animals. Snails of the species ''Bithynia'' are the first intermediate hosts, fish belonging to the family Cyprinidae are the second intermediate host, and the definitive hosts are humans and other mammals such as dogs, cats, rats, and pigs. It was first discovered in the Indian fishing cat (''Prionailurus viverrus'') by M.J. Poirier in 1886. The first human case was discovered by Robert Thomson Leiper in 1915. ''O. viverrini'' (together with ''Clonorchis sinensis'' and ''Opisthorchis felineus'') is one of the three mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver Fluke
Liver fluke is a collective name of a polyphyletic group of parasitic trematodes under the phylum Platyhelminthes. They are principally parasites of the liver of various mammals, including humans. Capable of moving along the blood circulation, they can occur also in bile ducts, gallbladder, and liver parenchyma. In these organs, they produce pathological lesions leading to parasitic diseases. They have complex life cycles requiring two or three different hosts, with free-living larval stages in water. Biology The body of liver flukes is leaf-like and flattened. The body is covered with a tegument. They are hermaphrodites having complete sets of both male and female reproductive systems. They have simple digestive systems and primarily feed on blood. The anterior end is the oral sucker opening into the mouth. Inside, the mouth leads to a small pharynx which is followed by an extended intestine that runs through the entire length of the body. The intestine is heavily branched and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bladder Cancer
Bladder cancer is any of several types of cancer arising from the tissues of the urinary bladder. Symptoms include blood in the urine, pain with urination, and low back pain. It is caused when epithelial cells that line the bladder become malignant. Risk factors for bladder cancer include smoking, family history, prior radiation therapy, frequent bladder infections, and exposure to certain chemicals. The most common type is transitional cell carcinoma. Other types include squamous cell carcinoma and adenocarcinoma. Diagnosis is typically by cystoscopy with tissue biopsies. Staging of the cancer is determined by transurethral resection and medical imaging. Treatment depends on the stage of the cancer. It may include some combination of surgery, radiation therapy, chemotherapy, or immunotherapy. Surgical options may include transurethral resection, partial or complete removal of the bladder, or urinary diversion. The typical five-year survival rates in the United States i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Haematobium
''Schistosoma haematobium'' (urinary blood fluke) is a species of digenetic trematode, belonging to a group (genus) of blood flukes (''Schistosoma''). It is found in Africa and the Middle East. It is the major agent of schistosomiasis, the most prevalent parasitic infection in humans. It is the only blood fluke that infects the urinary tract, causing urinary schistosomiasis, and is the leading cause of bladder cancer (only next to tobacco smoking). The diseases are caused by the eggs. Adults are found in the venous plexuses around the urinary bladder and the released eggs travels to the wall of the urine bladder causing haematuria and fibrosis of the bladder. The bladder becomes calcified, and there is increased pressure on ureters and kidneys otherwise known as hydronephrosis. Inflammation of the genitals due to ''S. haematobium'' may contribute to the propagation of HIV. ''S. haematobium'' was the first blood fluke discovered. Theodor Bilharz, a German surgeon working in Cair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicobacter Pylori
''Helicobacter pylori'', previously known as ''Campylobacter pylori'', is a gram-negative, microaerophilic, spiral (helical) bacterium usually found in the stomach. Its helical shape (from which the genus name, helicobacter, derives) is thought to have evolved in order to penetrate the mucoid lining of the stomach and thereby establish infection. The bacterium was first identified in 1982 by the Australian doctors Barry Marshall and Robin Warren. ''H. pylori'' has been associated with cancer of the mucosa-associated lymphoid tissue in the stomach, esophagus, colon, rectum, or tissues around the eye (termed extranodal marginal zone B-cell lymphoma of the cited organ), and of lymphoid tissue in the stomach (termed diffuse large B-cell lymphoma). ''H. pylori'' infection usually has no symptoms but sometimes causes gastritis (stomach inflammation) or ulcers of the stomach or first part of the small intestine. The infection is also associated with the development of cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast Cancer
Breast cancer is cancer that develops from breast tissue. Signs of breast cancer may include a lump in the breast, a change in breast shape, dimpling of the skin, milk rejection, fluid coming from the nipple, a newly inverted nipple, or a red or scaly patch of skin. In those with distant spread of the disease, there may be bone pain, swollen lymph nodes, shortness of breath, or yellow skin. Risk factors for developing breast cancer include obesity, a lack of physical exercise, alcoholism, hormone replacement therapy during menopause, ionizing radiation, an early age at first menstruation, having children late in life or not at all, older age, having a prior history of breast cancer, and a family history of breast cancer. About 5–10% of cases are the result of a genetic predisposition inherited from a person's parents, including BRCA1 and BRCA2 among others. Breast cancer most commonly develops in cells from the lining of milk ducts and the lobules that supply these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bovine Leukemia Virus
Bovine leukemia virus (BLV) is a retrovirus which causes enzootic bovine leukosis in cattle. It is closely related to the human T‑lymphotropic virus type 1 ( HTLV-I). BLV may integrate into the genomic DNA of B‑lymphocytes as a DNA intermediate (the provirus), or exist as unintegrated circular or linear forms. Besides structural and enzymatic genes required for virion production, BLV expresses the Tax protein and microRNAs involved in cell proliferation and oncogenesis . In cattle, most infected animals are asymptomatic; leukemia is rare (about 5% of infected animals), but lymphoproliferation is more frequent (30%). Vectors BLV is vectored by insects ''Anopheles albimanus'', ''Anopheles freeborni'', ''Anopheles quadrimaculatus'', ''Anopheles stephensi'', '' Stomoxys calcitrans'', and various ''Tabanidae'' including ''Tabanus atratus'' and '' Tabanus fuscicostatus'' and by the tick ''Boophilus microplus''. Disease in cattle Transmission Many potential routes of BLV transmissi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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