Carcinogenesis definition

Anti-neoplastic activity of UDCA was demonstrated first in the context of ulcerative colitis-associated colorectal carcinogenesis. Subsequently, encouraging (but not definitive) results have been obtained in clinical trials of UDCA for prevention of sporadic colorectal adenoma recurrence, which should prompt further evaluation of UDCA for polyp prevention, particularly given its excellent safety profile compared with other candidate chemoprevention agents such as the nonsteroidal anti-inflammatory drugs. 

Just within the past decade have definitive animal studies for arsenic-induced carcinogenesis emerged with positive results (Kitchin, 2001 Hughes, 2002 Rossman, 2003 Wanibuchi et al., 2004 Cohen et al., 2006 Waalkes, Liu and Diwan, 2007). Up until this point, standard lifetime cancer bioassays with inorganic... 

However, most public concern does not center around death or other acute intoxication symptoms, but rather those chronic injuries which we term as irreversible. These are carcinogenesis (cancer), teratogenesis (birth defects), or mutagenesis (genetic defects). There have been three good studies involving the ability of 2,4-D to cause cancer. The conclusion by the authors of these three studies is that there is no evidence that 2,4-D causes cancer. However, the study design was such that they were not adequate to prove that 2,4-D could not cause cancer, and as a result, further cancer studies were required by the EPA which should provide a definitive answer. 

These results implicate BHT as having a role in the activation, initiation or early promotional phase of DMBA-induced chemical carcinogenesis. A definite possibility is that it may require this period of time to allow for the induction of specific metabolic enzymes involved in the handling of DMBA. This time may be required for the attainment of sufficient levels in the tissues to allow effectiveness as an inhibitor. Further studies are certainly needed to narrow the wide range of possibilities. 

For brief definitions of various terms associated with carcinogenesis, refer to the glossary at the end of this entry. 

Several features of the carcinogenicity results on ethylene thiourea deserve discussion. Not all of the animals in a given dose group developed thyroid tumors over the course of their exposures only a fraction of each group did. Another name for this fraction is lifetime tumor incidence still another is lifetime risk (probability) of tumor development. Second, the lifetime risk of tumor development, or, since in the definition of carcinogenesis tumors were equated with can-... 

Carcinogenesis. Surviving victims of mustard exposure during the Iran-haq War are exhibiting carcinoma of the nasopharynx, bronchogenic carcinoma, adenocarcinoma of the stomach, as well as acute myeloblastic and lymphoblastic leukemia (Balali-Mood and Hefazi, 2006). Definitive studies of the nature and types of cancers seen in this patient population and correlations with severity of exposure have yet to be published. 

Chemical carcinogenesis (i.e., the production of malignancies by direct application of, or other exposure to, certain chemical substances) has been recognized for many years. However, sophisticated studies of the molecular mechanisms of carcinogenesis have only been undertaken during the past two or three decades. Unfortunately, few definitive answers have emerged. 

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