| LAF | laminar air flow; Latin American female; leukocyte-activating factor; lymphocyte-activating factor |
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| LF | labile factor; lactoferrin; laryngofissure; Lassa fever; latex fixation; left foot; left forearm; le... |
| LRF | latex and resorcinol formaldehyde; liver residue factor; luteinizing hormone-releasing factor |
| LRSF | lactating rat serum factor; liver regenerating serum factor |
| LTF | lactotransferrin; lipotropic factor; lymphocyte-transforming factor |
| tumour | 1. <oncology> An abnormal mass of tissue that results from excessive cell division that is uncontrolled and progressive, also called a neoplasm. Tumours perform no useful body function. They may be either benign (not cancerous) or malignant. 2. Swelling, one of the cardinal signs of inflammations, morbid enlargement. Origin: L. Tumere = to swell (12 May 1997) |
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| tumour antigens | Antigens that may be frequently associated with tumours or may be specifically found on tumour cells of the same origin (tumour specific), tumour antigens may also be associated with replication and transformation by certain DNA tumour viruses, including adenoviruses and papovaviruses. Synonym: neoantigens. See: T antigens. (05 Mar 2000) |
| tumour-associated antigen | Antigens that are highly correlated with certain tumour cells. They are not usually found, or are found to a lesser extent, on normal cells. (05 Mar 2000) |
| tumour burden | <oncology> The size of the tumour or number of abnormal cells in the organ or tissue. (16 Dec 1997) |
| tumour cell | <oncology> Cell derived from a tumour in an animal. Refers to a tumour causing malignant cell and not an adventitious normal cell. Loosely, a transformed cell able to give rise to tumours. (18 Nov 1997) |
| tumour cells, cultured | Cells grown in vitro from neoplastic tissue for use in studying the proliferative and metabolic capacities of tumour cells, in predicting clinical responses to chemotherapy, in screening new antitumour agents, and in basic biological research. They include carcinoma cell lines. (12 Dec 1998) |
| tumour debulking | Surgically removing as much of the tumour as possible. (12 Dec 1998) |
| tumour embolism | Embolism by neoplastic tissue transported from a tumour site and which may grow as a metastasis. (05 Mar 2000) |
| tumour escape | The ability of tumours to evade destruction by the immune system. Theories concerning possible mechanisms by which this takes place involve both cellular and humoral immunity, and also costimulatory pathways related to CD28 antigens and CD80 antigens. (12 Dec 1998) |
| tumour-infiltrating lymphocyte | <haematology, oncology> Special cancer-fighting cells of the immune system found in tumours. In a type of experimental therapy, scientists harvest these cells from the tumour, grow them in a laboratory and then return them to the patient with the hope of the cells destroying the tumour. These cells can be collected from the site of a tumour and exposed to IL-2 in vitro. When these cells are injected back into the tumour bearing host, they will specifically kill the tumour from which they originated. (05 Mar 2000) |
| tumour initiation | <cell biology, oncology> First stage of tumour development. See: tumour progression. (18 Nov 1997) |
| tumour lysis syndrome | <haematology, oncology, syndrome> A syndrome resulting from cytotoxic therapy, occurring generally in aggressive, rapidly proliferating lymphoproliferative disorders. It is characterised by combinations of hyperuricaemia, lactic acidosis, hyperkalaemia, hyperphosphatemia and hypocalcaemia. (12 Dec 1998) |
| tumour marker | <investigation, oncology> A substance in the body that usually indicates the presence of cancer. These markers are usually specific to certain types of cancer and are usually found in the blood or other tissue samples. Examples are alphafetoprotein (AFP), human chorionic gonadotropin, and lactate dehydrogenase (LDH). They may be indicators of tumour stage and grade as well as useful for monitoring responses to treatment and predicting recurrence. Many chemical groups are represented including hormones, antigens, amino and nucleic acids, enzymes, polyamines, and specific cell membrane proteins and lipids. (18 Jul 2002) |
| tumour progression | <oncology> Second stage of tumour development. See: tumour initiation. (18 Nov 1997) |
| tumour promoter | <molecular biology, oncology> Agent that in classical studies of carcinogenesis in rodent skin was able to increase the sensitivity of tumour formation by a previously applied primary carcinogen, but was unable to induce tumours when used alone. Important example was croton oil, active ingredients of which are now believed to be phorbol esters. These are believed to act as analogues of diacylglycerols and may activate protein kinase C. Strictly speaking, not the same as a co carcinogen, which is defined as being active when administered at the same time. Tumour promoters generally are carcinogens when tested more stringently. (18 Nov 1997) |