Navigation Links
Tumor


See the article about cancer for the main article about malignant tumors.

Tumor (American English) or tumour (British English) originally means "swelling", and is sometimes still used with that meaning. Tumor meaning swelling is one of the five classical characteristics of inflammation. However, the term is now primarily used to denote abnormal growth of tissue. This growth can be either malignant or benign.

Malignant tumors are called cancer. Cancer has the potential to invade and destroy neighboring tissues and create metastases. Benign tumors do not invade neighboring tissues and do not seed metastases, but may locally grow to great size. They usually do not return after surgical removal.

Depending on tissue of origin, tumors may be:


An epithelial tumor is considered malignant if it penetrates the basal lamina and is considered benign if it does not.

Tumors are caused by mutations in DNA of cells. An accumulation of mutations is needed for a tumor to emerge. Mutations that activate oncogenes or repress tumor supressor genes can eventually lead to tumors. Cells have mechanisms that repair DNA and other mechanisms that cause the cell to destroy itself by committing 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 oncogen or one tumor repressor gen is usually not enough for a tumor to occur. A combination of a number of mutations is necessary.

DNA microarrays can be used to determine if oncogens or tumor repressor gens have been mutated. Possibly in the future tumors can be treated better by using DNA microarrays to determine the exact characteristics of the tumor.

As people get older, they accumulate more mutations in their DNA. This means that the prevalence of tumors increases strongly with increasing age. It is also the case that the older a person with a tumor is, the higher the chances are that the tumor is malignant. For example, if a woman of 20 years old has a tumor in her breast it is very likely that the tumor is benign. However, if a woman of 70 has a tumor in her breast it is almost certain that it is malignant.

See also


'"/>


(Date:2/21/2017)... -- Der weltweite Biobanking-Sektor wird bis zum ... mit mehr als 50 Vertretern aus verschiedenen Branchen wurde aber ... diese Prognose zu realisieren. ... Zu den Schwierigkeiten für ... für die Biobank, die Implementierung Zeit sparender Technologien, ein ...
(Date:2/13/2017)... SAN FRANCISCO , Feb. 13, 2017 /PRNewswire/ ... a centralized platform that is designed to enhance ... the latest release in the RSA Fraud & ... to enable organizations to leverage additional insights from ... anti-fraud tools to better protect their customers from ...
(Date:2/9/2017)... The biomass boiler market report by Transparency Market Research ... in terms of revenue (US$ Mn) based on the ... boilers has been segmented on the basis of feedstock ... based on feedstock type, has been segmented into woody ... urban residues, and others. On the basis of product ...
Breaking Biology News(10 mins):
Other biology definition