Flow cytometry is a diagnostic and research technique known for many years and widely used in oncology. Flow cytometry allows the cells that make up suspension in a laminar, or stratified, liquid stream to be examined with a device called a flow cytometer. What are the indications for flow cytometry and how is it done?
Flow cytometryis used in the diagnosis of hematological neoplasms because they are liquid tumors, but it is only an auxiliary method. However, it is worth remembering that there is one cancer that can only be diagnosed with this method. This is chronic lymphocytic leukemia.
In other neoplastic diseases, flow cytometry is used as a diagnostic aid as it shows very important features of neoplastic cells. This method is also used to evaluate the effectiveness of the applied treatment.
Flow cytometry - what does it show?
The liquid stream containing the test particles flows at a constant speed (100-2000 particles per second) through the measuring area of the cytometer. Here, optical methods are used to analyze shapes, dimensions, internal structure of cells and their content, eg DNA. All cells are optically labeled.
The scattering properties of laser light by individual cells or their components (nuclei, chromosomes, mitochondria) or the fluorescence induced by them are used for measurements.
Optical signals are converted into electrical signals which, after analysis, are graphically presented in the form of mono- or biparametric distributions.
The cytometer also enables particle segregation after exiting the measurement zone. It can be said that the apparatus arranges (segregates) cells with the same constituent elements (preparative sort) or extracts specific types of cells (analytical sort).
Flow cytometry enables the study of population characteristics of cells, analysis of cellular components (especially such as nucleic acids, proteins, surface and cell antigens), enzymatic activity, membrane potential, mitochondrial activity, intracellular pH, ion transport and membrane fluidity.
Flow cytometry - application
Used in diagnosticsflow cytometry allows to determine the phenotype of neoplastic cells and the expression of individual proteins. To achieve this, labeled fluorescent antibodies are used which bind in a characteristic manner to antigens on the surface of the cell membrane. Thanks to this, it is possible to determine the degree of their differentiation, origin, prognostic and therapeutic markers, which facilitate the decision on further diagnostic and therapeutic procedures.
Another application for flow cytometry is monitoring the effectiveness of the treatment applied, by assessing the so-called "residual disease", which is the percentage of cells with tumor-like phenotypes that remain after treatment.
Flow cytometry also facilitates cancer research. Thanks to this method, it is possible to search, for example, for receptors that are on the surface of neoplastic cells and which can become the target of treatment.
The method allows you to evaluate the activity of proteins inside the cell. It is also possible to assess the cell cycle, e.g. by determining the amount of DNA in the cell.
In the course of proliferation, a cell goes through phases in the cell cycle in which it doubles the amount of DNA. By assessing this amount, it is possible to indicate what phase the cells are in, whether they are proliferating or not, or whether they are going into apoptosis. In other words, with the help of flow cytometry you can find out if the cells are preparing for apoptosis, which is the process of programmed death.
Flow cytometry - the future
Flow cytometry has been known and used in medicine for several dozen years. However, it is constantly being improved and creates more and more new diagnostic and research possibilities. In the first period of using this method, it was only possible to determine the size and degree of granularity of cells.
The use of laser light in flow cytometry devices allows you to excite certain fluorescent markers and then evaluate their emission. Modern cytometers allow a significant increase in the number of markers that are assessed at one time, which definitely translates into an increase in the sensitivity of this method.
That is why it is used not only in the diagnosis of neoplastic diseases, but also to assess the effectiveness of the treatment.
About the author
Anna Jarosz A journalist who has been involved in popularizing he alth education for over 40 years. Winner of many competitions for journalists dealing with medicine and he alth. She received, among others The "Golden OTIS" Trust Award in the "Media and He alth" category, St. Kamila awarded on the occasionWorld Day of the Sick, twice "Crystal Pen" in a nationwide competition for journalists promoting he alth, and many awards and distinctions in competitions for the "Medical Journalist of the Year" organized by the Polish Association of Journalists for He alth.
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