NationMaster - Encyclopedia: Tumor

Tumor or tumour (via Old French tumour from Latin tumor "swelling") is an abnormal growth or mass of tissue. A tumor can be either malignant or benign. Nearly all tumors are examples of neoplasia, although certain developmental malformations or inflammatory masses may occasionally be referred to as tumors. Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... Old French was the Romance dialect continuum spoken in territories corresponding roughly to the northern half of modern France and parts of modern Belgium and Switzerland from around 1000 to 1300. ... For other uses, see Latin (disambiguation). ... Biological tissue is a collection of interconnected cells that perform a similar function within an organism. ... For other uses, see Cancer (disambiguation). ... Tumor (American English) or tumour (British English) originally means swelling, and is sometimes still used with that meaning. ... Neoplasia (new growth in Greek) is abnormal proliferation of cells in a tissue or organ. ... A hamartoma is a common benign tumor in an organ composed of tissue elements normally found at that site but that are growing in a disorganized mass. ... An abscess on the skin, showing the redness and swelling characteristic of inflammation. ...

Causes

Neoplastic tumors are caused by mutations in DNA of cells, which interfere with a cell's ability to regulate and limit cell division. An accumulation of mutations is needed for a tumor to emerge. Mutations that activate oncogenes or repress tumor suppressor genes can eventually lead to tumors. Cells have mechanisms that repair DNA and other mechanisms that cause the cell to destroy itself by apoptosis if DNA damage gets too severe. Mutations that repress the genes for these mechanisms can also eventually lead to cancer. A mutation in one oncogene or one tumor repressor gene is usually not enough for a tumor to occur. A combination of a number of mutations is necessary. It has been suggested that mutant be merged into this article or section. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... This article or section includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... This does not adequately cite its references or sources. ... An oncogene is a modified gene that increases the malignancy of a tumor cell. ... A tumor suppressor gene is a gene that reduces the probability that a cell in a multicellular organism will turn into a tumor cell. ... A section of mouse liver showing an apoptotic cell indicated by an arrow Apoptosis (pronounced apo tÅ sis) is a process of suicide by a cell in a multicellular organism. ...

More recently, it has emerged that some human cancers, particularly epithelial cancers, are caused by virus infection. One common group of cancer-causing viruses are members of the Herpesvirus family, which can cause cancers such as Kaposi Sarcoma. A recent vaccine for the causative agent of many forms of genital warts, human papillomavirus (HPV), was publicised as a vaccine against cervical cancer, as HPV causes nearly all primary cervical cancers. Genera Subfamily Alphaherpesvirinae Simplexvirus Varicellovirus Mardivirus Iltovirus Subfamily Betaherpesvirinae Cytomegalovirus Muromegalovirus Roseolovirus Subfamily Gammaherpesvirinae Lymphocryptovirus Rhadinovirus Unassigned Ictalurivirus The Herpesviridae are a family of DNA viruses that cause diseases in humans and animals. ... â€œHPVâ€ redirects here. ...

DNA microarrays can be used to determine if the expression of oncogenes or tumor repressor genes has been altered. Possibly in the future tumors can be treated better by using DNA microarrays to determine the exact characteristics of the tumor. It has been suggested that Gene chip technology be merged into this article or section. ...

See also

For the server security software, see Microsoft Forefront. ... Tumor markers are substances found in the blood, urine or body tissues that can be elevated in cancer. ...

References

Categories: Anatomical pathology | Oncology A renal cell carcinoma (chromophobe type) viewed on a hematoxylin & eosin stained slide Pathologist redirects here. ... Neoplasia (new growth in Greek) is abnormal proliferation of cells in a tissue or organ. ... See cancer for the biology of the disease, as well as a list of malignant diseases. ... Hyperplasia (or hypergenesis) is a general term for an increase in the number of the cells of an organ or tissue causing it to increase in size. ... A cyst (soft c, rhymes with list) is a closed sac having a distinct membrane and develosion on the nearby tissue. ... A pseudocyst is a pathological collection of fluid. ... A hamartoma is a common benign tumor in an organ composed of tissue elements normally found at that site but that are growing in a disorganized mass. ... Benign can refer to any medical condition which, untreated or with symptomatic therapy, will not become life-threatening. ... Dysplasia (from Greek, roughly: bad form) is a term used in pathology to refer to an abnormality in maturation of cells within a tissue. ... Carcinoma in situ is present when a tumor has been detected that has the characteristics of malignancy but has not invaded other tissues. ... Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these to spread, either by direct growth into adjacent tissue through invasion, or by implantation into distant sites by metastasis (where cancer cells are transported through the bloodstream or lymphatic system). ... For the musical composition, see Metastasis (Xenakis composition). ... Anal cancer is a distinct entity from the more common colorectal cancer. ... Bladder cancer refers to any of several types of malignant growths of the urinary bladder. ... Leukemia or leukaemia (see spelling differences) is a cancer of the blood or bone marrow and is characterized by an abnormal proliferation (production by multiplication) of blood cells, usually white blood cells (leukocytes). ... // [edit] Introduction Cholangiocarcinoma is an adenocarcinoma of the biliary duct system. ... An arm bone tumor Bone tumor is an inexact term, which can be used for both benign and malignant abnormal growths found in bone, but is most commonly used for primary tumors of bone, such as osteosarcoma (or osteoma). ... A brain tumor is any intracranial tumor created by abnormal and uncontrolled cell division, normally either in the brain itself (neurons, glial cells (astrocytes, oligodendrocytes, ependymal cells), lymphatic tissue, blood vessels), in the cranial nerves (myelin-producing Schwann cells), in the brain envelopes (meninges), skull, pituitary and pineal gland, or... Breast cancer is cancer of breast tissue. ... Cervical cancer is a malignant cancer of the cervix. ... Colorectal cancer, also called colon cancer or bowel cancer, includes cancerous growths in the colon, rectum and appendix. ... Endometrial cancer involves cancerous growth of the endometrium (lining of the uterus). ... Esophageal cancer is malignancy of the esophagus. ... Ocular oncology is the branch of medicine dealing with tumors relating to the eye and its adnexa. ... Bold textA more uncommon cancer predominate in females, if found early on before symptoms, can be cured by removing Gallbladder, most often it is found after symptoms occur (abdominal pain, Jaundice) and has spread to other organs such as liver and the outlook at this point is poor. ... Head and neck cancers are malignant growths originating in the lip and oral cavity (mouth), nasal cavity, pharynx, larynx, thyroid, paranasal sinuses, salivary glands and cervical lymph nodes of the neck. ... Hepatocellular carcinoma (HCC, also called hepatoma) is a primary malignancy (cancer) of the liver. ... Renal cell carcinoma is the most common form of kidney cancer arising from the renal tubule. ... Cancer of the larynx also may be called laryngeal cancer. ... Lung cancer is the malignant transformation and expansion of lung tissue, and is the most lethal of all cancers worldwide, responsible for 1. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Oral cancer is any cancerous tissue growth located in the mouth. ... Ovarian cancer is a malignant tumor (a kind of neoplasm) located on an ovary. ... Pancreatic cancer is a malignant tumour within the pancreatic gland. ... Penile cancer is a malignant growth found on the skin or in the tissues of the penis, usually originating in the glans and/or foreskin. ... Prostate cancer is a disease in which cancer develops in the prostate, a gland in the male reproductive system. ... Skin cancer is a malignant growth on the skin which can have many causes. ... Endoscopic image of adenocarcinoma of duodenum seen in the post-bulbar duodenum. ... Stomach cancer (also called gastric cancer) can develop in any part of the stomach and may spread throughout the stomach and to other organs; particularly the esophagus and the small intestine. ... Sacrococcygeal teratoma (SCT), a birth defect, is a tumor located at the base of the tailbone (coccyx). ... Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system. ... A tumor suppressor gene is a gene that reduces the probability that a cell in a multicellular organism will turn into a tumor cell. ... An oncogene is a modified gene that increases the malignancy of a tumor cell. ... The stage of a cancer is a descriptor (usually numbers I to IV) of how much the cancer has spread. ... In pathology, Grading is a measure of the progress of tumors. ... Cancers are caused by a series of mutations. ... The hazard symbol for carcinogenic chemicals in the Globally Harmonized System. ... Cancer research is research into cancer in order to identify causes and develop strategies for prevention, diagnosis, treatments and cure. ... A paraneoplastic phenomenon is a disease or symptom that is the consequence of the presence of cancer in the body, but is not due to the local presence of cancer cells. ... This is a list of terms related to oncology. ...

Encyclopedia > Tumor

Causes

See also

References