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CA19-9 Definition ! Carbohydrate antigen 19-9.

CA125 Definition CA125 is an antigen often secreted by ! ovarian cancer cells, which can be used as an ovarian tumor marker. It is elevated in some cases of endometriosis.

CAAT Box Definition The CAAT box is part of a conserved sequence located upstream of the startpoints of eukaryotic transcription units. It is recognized by a large group of transcription factors.

Cachexia Chen Bing, Gareth Williams Department of Medicine University of Liverpool, Liverpool, UK [email protected], [email protected]

Definition Cachexia is a complex metabolic syndrome characterised by marked weight loss together with poor appetite, weakness and often anemia, which is secondary to the growing malignancy.

Characteristics Most cancer patients develop cachexia at some point during the course of their disease, and nearly one-half of all cancer patients have weight loss at diagnosis. Cachexia causes a poor prognosis: the severity of wasting is inversely correlated with survival. The causes of cancer cachexia syndrome are not fully understood, but it is evidently multifactorial. Weight loss The most apparent clinical manifestation of cancer cachexia is weight loss that affects both skeletal muscle (lean tissue) and body fat. Weight loss is not simply caused by competition for nutrients between tumour and host, as the tumour burden may be only 1-2% of total body weight, and patients with even smaller tumours are often markedly cachectic. The frequency of weight loss varies with the type of malignancy, from 31% in non-Hodgkin's lymphoma to 87% in patients with gastric carcinomas. Gastric and pancreatic cancer patients

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may lose large amounts of weight, up to 25% of initial weight. Over 15% of weight loss in patients are likely to cause significant impairment of respiratory muscle function, which probably leads to premature death. Weight loss can arise from several metabolic changes that occur during malignancy, for example, reduced food intake, increased energy expenditure and tissue breakdown. Poor appetite Loss of the desire to eat or lack of hunger is common in cancer patients, and it can be related to the mechanical effect of the tumour (especially of the upper gastrointestinal tract), side-effects of chemotherapy or radiotherapy and emotional distress. Some tumours may secrete products that act on the brain to inhibit appetite. Regulation of food intake involves the integration of blood-borne and neural signals in the hypothalamus at the base of the brain. Cytokines such as interleukin 1 (IL-1) and tumour necrosis factor-alpha (TNF-a) have been proposed to be involved in cancerrelated anorexia, possibly by increasing brain levels of corticotropin-releasing factor (CRF), a hypothalamic neurotransmitter that suppresses food intake at least in rodents, and/ or inhibiting neurones that produce neuropeptide Y (NPY), a potent appetite stimulant. Hypermetabolism and increased energy expenditure Maintaining normal body weight requires energy intake to equal energy expenditu