Proteins of the Bcl-2 family are regulators of apoptosis (programmed cell death) localized to membranes of primarily mitochondria, but also to smooth endoplasmic reticulum and nucleolemma. The fine balance between pro- and anti-apoptotic Bcl-2 family members regulates the cell fate in response to many signalling pathways. Altered expression of the proteins may lead to either premature cell death or to inappropriate cell survival promoting neoplastic growth. Bcl-2, Bax and Bcl-X are the most well known proteins in this family. In neoplastic lesions Bcl-2 upregulation may act by suppression of programmed cell death and extension of the tumour cell life span. Bcl-2 overexpression contributes to increased resistance to chemotherapy. However, the prognostic value of Bcl-2 overexpression is dependent on the tumour type, and in some types BCl-2 may even have a tumour suppressor effect. Overexpression of Bcl-2 is common in many types of cancer, including non-Hodgkin's lymphoma and leukaemias, adenocarcinomas (e.g., prostate, colorectum, stomach, and lung), squamous cell carcinoma, small cell carcinoma, neuroblastoma and various sarcomas. Bcl-2 is helpful in distinguishing follicular lymphoma from reactive follicular hyperplasia. Bcl-2 staining can not be used for differential diagnosis between follicular lymphoma and other types of low-grade B-cell lymphomas since most of the latter also express bcl-2. Monocytoid B-cell hyperplasia contrasts with bcl-2 negativity against positive reaction in 80% of the marginal zone lymphomas. Possibly, Bcl-2 may aid in the differential diagnosis of sarcomas. Tonsil is recommendable as positive and negative tissue control for BCL2. A moderate to strong, predominantly cytoplasmic staining reaction should be displayed in virtually all T-cells and B-cells in the mantle zone of the reactive follicles, whereas the majority of the basal squamous epithelial cells, e.g. lining the tonsillar crypts, must show an at least weak staining intensity. Germinal centre T-cells should be distinctively demonstrated, whereas germinal centre B-cells should be negative.
1034.88RON
În stoc
Număr Catalog 992-HA721235CategorieAfaceri și industrie > Știință și laboratorFurnizorHUABIOGentaurDimensiune100ulTipsingle
