Related topics: cancer · breast cancer · cells · tumor cells · protein

Preventing drugs from being transported from cells

An international research team has investigated the transport mechanism of a bacterial membrane protein using an artificially produced antibody fragment. The transport proteins, called ABC exporters, are present, for instance, ...

Research uncovers elusive process essential to plant greening

Despite how essential plants are for life on Earth, little is known about how parts of plant cells orchestrate growth and greening. By creating mutant plants, UC Riverside researchers have uncovered a cellular communication ...

A homing beacon for chemotherapy drugs

Killing tumor cells while sparing their normal counterparts is a central challenge of cancer chemotherapy. If scientists could put a "homing beacon" in tumors, they could attract these medicines and reduce side effects caused ...

Is sex primarily a strategy against transmissible cancer?

One of the greatest enigmas of evolutionary biology is that while sex is the dominant mode of reproduction among multicellular organisms, asexual reproduction appears much more efficient and less costly. However, in a study ...

DNA nanorobots target HER2-positive breast cancer cells

According to the Mayo Clinic, about 20% of breast cancers make abnormally high levels of a protein called human epidermal growth factor receptor 2 (HER2). When displayed on the surface of cancer cells, this signaling protein ...

Separation anxiety no more: A faster technique to purify elements

The actinides—those chemical elements on the bottom row of the periodic table—are used in applications ranging from medical treatments to space exploration to nuclear energy production. But purifying the target element ...

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Cancer

Cancer (medical term: malignant neoplasm) is a class of diseases in which a group of cells display uncontrolled growth (division beyond the normal limits), invasion (intrusion on and destruction of adjacent tissues), and sometimes metastasis (spread to other locations in the body via lymph or blood). These three malignant properties of cancers differentiate them from benign tumors, which are self-limited, and do not invade or metastasize. Most cancers form a tumor but some, like leukemia, do not. The branch of medicine concerned with the study, diagnosis, treatment, and prevention of cancer is oncology.

Cancer may affect people at all ages, even fetuses, but the risk for most varieties increases with age. Cancer causes about 13% of all human deaths. According to the American Cancer Society, 7.6 million people died from cancer in the world during 2007. Cancers can affect all animals.

Nearly all cancers are caused by abnormalities in the genetic material of the transformed cells. These abnormalities may be due to the effects of carcinogens, such as tobacco smoke, radiation, chemicals, or infectious agents. Other cancer-promoting genetic abnormalities may be randomly acquired through errors in DNA replication, or are inherited, and thus present in all cells from birth. The heritability of cancers are usually affected by complex interactions between carcinogens and the host's genome. New aspects of the genetics of cancer pathogenesis, such as DNA methylation, and microRNAs are increasingly recognized as important.

Genetic abnormalities found in cancer typically affect two general classes of genes. Cancer-promoting oncogenes are typically activated in cancer cells, giving those cells new properties, such as hyperactive growth and division, protection against programmed cell death, loss of respect for normal tissue boundaries, and the ability to become established in diverse tissue environments. Tumor suppressor genes are then inactivated in cancer cells, resulting in the loss of normal functions in those cells, such as accurate DNA replication, control over the cell cycle, orientation and adhesion within tissues, and interaction with protective cells of the immune system.

Diagnosis usually requires the histologic examination of a tissue biopsy specimen by a pathologist, although the initial indication of malignancy can be symptoms or radiographic imaging abnormalities. Most cancers can be treated and some cured, depending on the specific type, location, and stage. Once diagnosed, cancer is usually treated with a combination of surgery, chemotherapy and radiotherapy. As research develops, treatments are becoming more specific for different varieties of cancer. There has been significant progress in the development of targeted therapy drugs that act specifically on detectable molecular abnormalities in certain tumors, and which minimize damage to normal cells. The prognosis of cancer patients is most influenced by the type of cancer, as well as the stage, or extent of the disease. In addition, histologic grading and the presence of specific molecular markers can also be useful in establishing prognosis, as well as in determining individual treatments.

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