الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Accurate diagnosis and classification of hematological malignancies (leukemia and lymphoma) is an essential step for proper treatment.This could be done by morphological, cytochemical, immunophenotypic, and cytogenetic as well as molecular studies. Among these methods immunophenotyping is a mandatory test for diagnosis, follow up through detection of minimal residual disease and sometimes for prognostic stratification. Immunophenotyping is a technique used to study the protein expressed either in the surface or inside the cells. This could be done by two techniques flow cytometry and immunohistochemistery applying monoclonal antibodies in both techniques. FCM provides a more precise definition of individual cell types through a combination of physical characteristics and the use of multiple antibodies directly conjugated with different fluorochromes. Applying multiple markers permits detection of multiple antigens on the same cell in a single procedure. Itassesses monoclonality by detecting immunoglobulin light chain expression. FCM is rapid since it requires fresh specimens to maintain viability and avoid loss of antigenicity through the process of fixation; processing of fresh tissue within minutes or a few hours is therefore mandatory. It is clearly an advantage that results are available within hours. However, fresh tissue is often not available in a clinical situation, leaving IHC as the most practical option. IHC allows the greatest sensitivity because of a combination of reasons: Excellent signal to background ratio, for high density antigens (>10K molecules/cell), with a simple indirect IHC. An equivalent IF immunostaining is less sensitive because none of the fluorochrome for which filters are commonly available (except possibly Cy-3) matches thesensitivity and the signal-to-background ratio. Fluorochromes such as PE or Cy-5 / APC, which are used in FCM and have very high quantum yield, either fade very rapidly (PE) or have special filter requirements, not usually found on epifluorescence microscopes. • For low density antigens (>2K,<10K molecules / cell), the only reliable and diffusely available signal amplification methods are in IHC. IHC has the advantage that the cells of interest are identified morphologically and can be used retrospectively on fixed tissues. However, only a single marker is routinely used on tissue sections, and some investigators have reported difficulty using IHC to characterize immunoglobulin light chains.