¿Qué es la prueba de FISH y cómo ayuda en la detección del cáncer?

Una de las enfermedades más temidas, complejas y fatales que se ha convertido en la causa de muerte para muchos es el cáncer. El cáncer es una enfermedad en la cual las células y los tumores se vuelven malignos y se diseminan de una manera poco saludable. El cáncer puede ocurrir en casi cualquier parte del cuerpo. Aunque la determinación temprana y el diagnóstico de cáncer pueden curar o al menos tratar la enfermedad; sin embargo, la mayoría de las veces, en la etapa temprana se hace difícil diagnosticar el cáncer, ya que los síntomas no son pronunciados. De hecho, las pruebas tampoco confirman la presencia de células malignas / cancerosas en el cuerpo con facilidad. Sin embargo, una prueba que es común y ampliamente utilizada para determinar el cáncer es la prueba FISH.

La prueba de FISH o la hibridación in situ de la fluorescencia es una prueba que se utiliza para detectar el cáncer mediante el “mapeo” de los materiales genéticos presentes en las células humanas. Para ser más específico, la prueba FISH es una rama de la genética que detecta y trata principalmente de localizar la presencia y la ausencia de secuencias específicas o particulares de ADN en los cromosomas. Esta prueba también se conoce como citogenética molecular.

Con esta prueba, se pueden detectar anomalías genéticas relacionadas con enfermedades como el cáncer. La mejor aplicación de la prueba FISH es determinar el tipo de cáncer. En esos casos, donde el tipo de cáncer ya ha sido detectado por alguna otra prueba, la prueba FISH ayuda a determinar si un paciente puede tomar medicamentos de quimioterapia y responder a este tratamiento contra el cáncer. El médico también requiere información adicional para determinar la condición del paciente y el resultado del cáncer; Ya sea que él o ella esté respondiendo al tratamiento del cáncer o no, la prueba FISH también ayuda a detectar esta información adicional. En la mayoría de los casos, esta prueba FISH se realiza para detectar el cáncer de mama, mediante la recolección de tejido de los tumores de mama durante la biopsia u otras cirugías.

La prueba FISH puede detectar si las células de cáncer de mama que contienen genes y ADN adicionales lo son.

  • Producing some particular proteins.
  • Prohibiting the cells to make the protein.
  • Making protein in large amounts than normal.

How is FISH Test Done?

Since FISH test is done to determine breast cancer in most of the cases, the mechanism of breast cells needs to be understood first. The breast cell contains HER2 gene in its chromosomes. The HER2 or Human Epidermal Growth Factor Receptor 2 is a receptor protein. The HER2 gene in a normal breast cell will instruct the cell to produce HER2 protein in proper amount. The HER2 receptor or protein gives the cell the instruction and sends signals telling the cell to grow itself and divide into more cells. When there are extra copies of the HER2 gene in the breast cell, the HER2-positive breast cells are deemed as cancer cells causing the cells to grow and divide more quickly.

During the test, samples of the cancer tissue are collected at first. They are then spread on slides to check if the cells have extra copies of HER2 genes. Those cells that have extra copies of the HER2 genes will have more HER2 receptors or produce more HER2 protein and are considered to be cancerous.

A special coloured dye is used to colour some parts of the specific chromosomes for determining its type. This helps the pathologist to count the chromosomes with proper visualizing opportunity, when the sample with the coloured dye attachment is placed under a fluorescent microscope. The dye works as a specific marker that will indicate any change in the DNA or the parts of the chromosomes and also help the pathologist to count the chromosome or genes, thereby determining the extra presence of these genes within the cancerous cells.

As the genetic markers or the fluorescent dye sticks to the genes, it clearly shines when the cells are placed under ultraviolet light in the fluorescent microscope. When the pathologist looks into the microscope, the dyed region is clearly shown as a brightly glowing area.

The Abnormalities that FISH Test Can Detect.

In case of breast cancer cells that are mostly determined by the FISH test, the fluorescent dye will clearly show that the HER2 gene as a more glowing region, since they are more in number than normal. However, in general and in all other cancer detections, the abnormalities that FISH test can find are.

  • Inversion. If some parts of the chromosome lies in a reverse order, despite being attached to the proper chromosome.
  • Translocation. When some parts of the chromosome gets broken and gets relocated to another chromosome.
  • Duplication. When parts of the chromosome are copied and there are too many duplicates in the cell.
  • Deletion. When parts of the chromosome gets deleted.

The other diseases that can also be detected with the help of FISH test or Fluorescence In-Situ Hybridization test are lymphoma, leukemia and also sarcoma. All these diseases are associated with the abnormality of the chromosome where parts of the chromosome get translocated.

What are the Advantages of FISH Test?

FISH Test Detects Minute Cell Changes. Since the genetic changes are very crucial to be identified by the pathologist in order to determine and detect the cancer cells,

FISH test or Fluorescence In-Situ Hybridization test is the best way to do this. This is because no other test can display the small genetic changes under the microscope like this one.

FISH Test Confirms Cancer In Its Initial Stages. As most of the cancer cells take about two weeks to grow and divide, when the sample is collected at the lab dish, the pathologist has to wait for weeks to let the sample cells grow and divide, in order to run the test. However, in FISH test, the active cell division is not required. Only the presence of these cell dividing extra copies of HER2 genes can detect the malignancy of these cells. Hence, the results can be determined within a few days.

Usage and Availability of the FISH test.

FISH test is quite an expensive test and is not widely popular, despite its accuracy and potential to detect some kinds of cancers. Moreover, it is still not known whether FISH test will be useful in determining and detecting all kinds of cancers or not. This is because the genes that should be looked for in order to perform the FISH test for different cancer cells are not yet known. Chronic lymphocytic leukaemia and breast cancer are the two common cancers that are best determined by FISH test. Lung cancer and stomach cancer are also being determined by FISH test.

Conclusion

The FISH or Fluorescence In Situ Hybridization test is a highly potential test for determining some cancers and other similar gene abnormality related diseases. The test is likely to be done and used more widely in the times to come.

Especialista en dolor at | 307-996-2960 | [email protected]

Soy un Neuroanestesiólogo y Especialista en el Tratamiento del Dolor. Me otorgaron el Premio Nacional de Medicina 2018. Soy CEO y fundador de la Unidad Internacional del Dolor de Madrid y editor de Journal Pain Management and Therapy. También es asesor y crítico del AIUM (Instituto Estadounidense de Ultrasonidos en Medicina) y miembro del Comité Organizador de las World Pain Conferences.

Tengo más de diez años de experiencia con terapias regenerativas que incluyen células madre mesenquimales, plasma rico en plaquetas, factores de crecimiento, transferencias de grasa y ácido hialurónico. Inicié Dolor-drdelgadocidranes.com para difundir el conocimiento y la conciencia.

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