IHC study – what is it, decoding of the results

IHC study – what is it, decoding of the results

24.05.2022 0 By admin

At present, a qualitative diagnosis of many oncological diseases is impossible without immunohistochemical studies. Immunohistochemical study (IHC study) is a method of microscopic examination of tissues. During the IHC study, tissue sections are processed with labeled specific antibodies to the substance to be detected.

This is a highly accurate and informative method that allows not only to identify a neoplasm, but also to develop optimal treatment tactics.

igh research what is it

IHC is mandatory for cancer of the lymphatic system, when the lymph nodes or internal organs are affected.

IHC research – what is it

IHC is a technique used in pathological anatomy for the diagnosis of cancerous and benign tumors. It is prescribed when it is impossible to establish an accurate diagnosis using a standard histological method or when it is necessary to detail the clinically significant parameters of neoplasms at the molecular level.

Very often, histology is not enough. In most cases, the reason for this is the extremely atypical structure of the pathological formation, which makes it difficult to make an accurate diagnosis. In particular, with lymphoma and leukemia, IHC is almost always done.

It should be noted that in total there are about 70 varieties of leukemia and lymphomas. It is possible to verify some of them only through several studies – histological, immunohistochemical and molecular genetic.

Another diagnosis – “small round cell tumor” – can mean 13 malignant tumors with different course and prognosis. In addition, each of them requires the development of a special scheme of chemotherapy and radiotherapy. Differentiation of such tumors helps the only method – immunohistochemistry.

The essence of the technique

With the development of any tumor process, proteins alien to the body are formed – antigens, in contrast to which the human immune system produces antibodies – immunoglobulins. They attach to antigens and bind to epitopes, the main parts of antigenic macromolecules. Antibodies perform two functions at once: binding and effector. Simply put, they directly prevent antigens from doing harm and at the same time activate complement, triggering an immune response.

The role of antigens in this case belongs to atypical tumor cells. Before conducting an immunohistochemical study, sections of the biomaterial are labeled with specific antibodies to them. For further visualization, these antibodies are stained with enzymes. Further, using high-precision optics, the behavior of the tested cells is observed.

If protein compounds labeled as antibodies bind to tumor cells, a glow will be seen – fluorescence, indicating the presence of the desired substances. So, for example, hormone receptors and tumor markers are detected. If breast cancer is suspected, estrogen and progesterone receptors are thus detected.

Who is shown

The main indication for the appointment of immunohistochemistry are malignant neoplasms. In oncology, this method is used to search for metastases and pathological microorganisms, determine the type and localization of the tumor, and also to assess the activity of the pathological process. With the help of IHC, it is possible to establish a final or, less often, an intermediate diagnosis in skin cancer (melanoma), sarcoma, lymphogranulomatosis, lymphocytic leukemia, and leukemia, and to type the degree of malignancy of the process. The latter is extremely important in neuroendocrine formations, which are also called “hidden killers” due to the fact that they are very difficult to recognize in the early stages.

Immunohistochemical testing is often done to avoid aggressive treatment with toxic drugs.

In some cases, immunohistochemical analysis makes it possible to establish the source of metastases when the localization of the primary focus is unknown, as well as to conduct differential diagnostics for several neoplasms of different origin.

IHC can be prescribed for infertility, chronic pathologies of the endometrium, uterus and ovaries, habitual miscarriages. It is also advisable to do it if pregnancy does not occur after several IVF procedures.

Immunohistochemistry will help detect the presence of cells that prevent conception, and determine further tactics for the treatment of infertility.

The IHC method also evaluates drug sensitivity by identifying:

  • sex hormone receptors – estrogen, progesterone and androgens. It is necessary for the defeat of the female reproductive system;
  • tumor growth factor Her2/neu. Biomarker and therapeutic target for aggressive types of breast cancer;
  • somatostatin receptors 2a and 5 types, important in carcinoids;
  • PD-L1 immunoglobulin membrane protein, ALK gene, and ROS tyrosine kinase receptor. These indicators are studied mainly in non-small cell lung cancer;
  • microsatellite instability;
  • index of proliferative activity.

It is difficult to overestimate the importance of microsatellite instability (MSI), which significantly expands the prognostic and therapeutic options in patients with malignant lesions of the gastrointestinal tract. Neoplasms with low MSI grow more slowly and metastasize less often. Therefore, timely detection of MSI avoids the appointment of aggressive, but obviously ineffective therapy.

How IHC studies are carried out

To perform IHC, a biomaterial is required, the collection of which is carried out mainly by taking a biopsy. Somewhat less often, it is obtained during endoscopic or classical open surgery. The method of removing the affected tissue depends on the type and location of the cancer. It should be noted that the material should be taken for analysis before the start of therapy. Otherwise, the results of the study may be distorted.

Analysis steps:

  1. The resulting biomaterial is fixed by processing in formalin and sent to the laboratory.
  2. Then it is degreased and re-fixed, after which it is filled with paraffin.
  3. Next, microtomy is performed – thin sections are made from the finished paraffin blocks, which are placed on special glasses. The cut thickness is no more than 1 µm.

To take the material, a biopsy of the tumor is prescribed or a tissue fragment is removed during surgery.

When the tissues lie on the slides, they are treated with labeled specific antibodies to the substance to be detected, which in this situation serves as an antigen. The number of their species is limited to a few dozen. The study of reactions using up to 5 different antibodies is carried out on a small panel. For a larger experiment, a larger panel is needed.

The final stage of the analysis is the immunohistochemical study itself, which is a method of microscopic examination of tissues. This method provides the most effective detection of the desired substances in tissue sections.

During IHC, cancer of any organ is manifested by the effect of luminescence – fluorescence – due to which malignant cells are detected, hormone receptors or other specified parameters are determined.

Decryption

Pathologists are engaged in the study of sections of biomaterial. They are the first to make a prognosis based on the identified type and volume of oncogenic cells. When deciphering the results, special attention is paid to the K-67 indicator – a specific protein, an antigen of the cancer process. It is produced only during active cell division, and is not produced at rest.

K-67 is exactly the oncomarker that shows the degree of malignancy of the process. If its level in percentage is 85% or higher, then the disease progresses rapidly and with a high probability will soon lead to death.

The forecast will be favorable at K-67=10%. In the case of a well-designed therapy plan, there is every chance for a complete recovery, often without the risk of relapse. At K=30%, the average severity of the disease is stated, which means a fairly rapid growth of cancer. With chemotherapy, it can be slowed down and even stopped.

However, K-67 is not the only indicator that is indicated in the medical report. Antibodies are also recorded, to which the corresponding antigens, the type and number of the latter have been identified.

The resulting conclusion is passed by the pathologist to the attending oncologist, who selects the treatment. To evaluate its effectiveness, immunohistochemistry is carried out again after the completion of the therapeutic course.

Video

Read more: Embryo PGD

Photo: © Depositphotos

IHC study – what is it, decoding of the results

24.05.2022 0 By admin

At present, a qualitative diagnosis of many oncological diseases is impossible without immunohistochemical studies. Immunohistochemical study (IHC study) is a method of microscopic examination of tissues. During the IHC study, tissue sections are processed with labeled specific antibodies to the substance to be detected.

This is a highly accurate and informative method that allows not only to identify a neoplasm, but also to develop optimal treatment tactics.

igh research what is it

IHC is mandatory for cancer of the lymphatic system, when the lymph nodes or internal organs are affected.

IHC research – what is it

IHC is a technique used in pathological anatomy for the diagnosis of cancerous and benign tumors. It is prescribed when it is impossible to establish an accurate diagnosis using a standard histological method or when it is necessary to detail the clinically significant parameters of neoplasms at the molecular level.

Very often, histology is not enough. In most cases, the reason for this is the extremely atypical structure of the pathological formation, which makes it difficult to make an accurate diagnosis. In particular, with lymphoma and leukemia, IHC is almost always done.

It should be noted that in total there are about 70 varieties of leukemia and lymphomas. It is possible to verify some of them only through several studies – histological, immunohistochemical and molecular genetic.

Another diagnosis – “small round cell tumor” – can mean 13 malignant tumors with different course and prognosis. In addition, each of them requires the development of a special scheme of chemotherapy and radiotherapy. Differentiation of such tumors helps the only method – immunohistochemistry.

The essence of the technique

With the development of any tumor process, proteins alien to the body are formed – antigens, in contrast to which the human immune system produces antibodies – immunoglobulins. They attach to antigens and bind to epitopes, the main parts of antigenic macromolecules. Antibodies perform two functions at once: binding and effector. Simply put, they directly prevent antigens from doing harm and at the same time activate complement, triggering an immune response.

The role of antigens in this case belongs to atypical tumor cells. Before conducting an immunohistochemical study, sections of the biomaterial are labeled with specific antibodies to them. For further visualization, these antibodies are stained with enzymes. Further, using high-precision optics, the behavior of the tested cells is observed.

If protein compounds labeled as antibodies bind to tumor cells, a glow will be seen – fluorescence, indicating the presence of the desired substances. So, for example, hormone receptors and tumor markers are detected. If breast cancer is suspected, estrogen and progesterone receptors are thus detected.

Who is shown

The main indication for the appointment of immunohistochemistry are malignant neoplasms. In oncology, this method is used to search for metastases and pathological microorganisms, determine the type and localization of the tumor, and also to assess the activity of the pathological process. With the help of IHC, it is possible to establish a final or, less often, an intermediate diagnosis in skin cancer (melanoma), sarcoma, lymphogranulomatosis, lymphocytic leukemia, and leukemia, and to type the degree of malignancy of the process. The latter is extremely important in neuroendocrine formations, which are also called “hidden killers” due to the fact that they are very difficult to recognize in the early stages.

Immunohistochemical testing is often done to avoid aggressive treatment with toxic drugs.

In some cases, immunohistochemical analysis makes it possible to establish the source of metastases when the localization of the primary focus is unknown, as well as to conduct differential diagnostics for several neoplasms of different origin.

IHC can be prescribed for infertility, chronic pathologies of the endometrium, uterus and ovaries, habitual miscarriages. It is also advisable to do it if pregnancy does not occur after several IVF procedures.

Immunohistochemistry will help detect the presence of cells that prevent conception, and determine further tactics for the treatment of infertility.

The IHC method also evaluates drug sensitivity by identifying:

  • sex hormone receptors – estrogen, progesterone and androgens. It is necessary for the defeat of the female reproductive system;
  • tumor growth factor Her2/neu. Biomarker and therapeutic target for aggressive types of breast cancer;
  • somatostatin receptors 2a and 5 types, important in carcinoids;
  • PD-L1 immunoglobulin membrane protein, ALK gene, and ROS tyrosine kinase receptor. These indicators are studied mainly in non-small cell lung cancer;
  • microsatellite instability;
  • index of proliferative activity.

It is difficult to overestimate the importance of microsatellite instability (MSI), which significantly expands the prognostic and therapeutic options in patients with malignant lesions of the gastrointestinal tract. Neoplasms with low MSI grow more slowly and metastasize less often. Therefore, timely detection of MSI avoids the appointment of aggressive, but obviously ineffective therapy.

How IHC studies are carried out

To perform IHC, a biomaterial is required, the collection of which is carried out mainly by taking a biopsy. Somewhat less often, it is obtained during endoscopic or classical open surgery. The method of removing the affected tissue depends on the type and location of the cancer. It should be noted that the material should be taken for analysis before the start of therapy. Otherwise, the results of the study may be distorted.

Analysis steps:

  1. The resulting biomaterial is fixed by processing in formalin and sent to the laboratory.
  2. Then it is degreased and re-fixed, after which it is filled with paraffin.
  3. Next, microtomy is performed – thin sections are made from the finished paraffin blocks, which are placed on special glasses. The cut thickness is no more than 1 µm.

To take the material, a biopsy of the tumor is prescribed or a tissue fragment is removed during surgery.

When the tissues lie on the slides, they are treated with labeled specific antibodies to the substance to be detected, which in this situation serves as an antigen. The number of their species is limited to a few dozen. The study of reactions using up to 5 different antibodies is carried out on a small panel. For a larger experiment, a larger panel is needed.

The final stage of the analysis is the immunohistochemical study itself, which is a method of microscopic examination of tissues. This method provides the most effective detection of the desired substances in tissue sections.

During IHC, cancer of any organ is manifested by the effect of luminescence – fluorescence – due to which malignant cells are detected, hormone receptors or other specified parameters are determined.

Decryption

Pathologists are engaged in the study of sections of biomaterial. They are the first to make a prognosis based on the identified type and volume of oncogenic cells. When deciphering the results, special attention is paid to the K-67 indicator – a specific protein, an antigen of the cancer process. It is produced only during active cell division, and is not produced at rest.

K-67 is exactly the oncomarker that shows the degree of malignancy of the process. If its level in percentage is 85% or higher, then the disease progresses rapidly and with a high probability will soon lead to death.

The forecast will be favorable at K-67=10%. In the case of a well-designed therapy plan, there is every chance for a complete recovery, often without the risk of relapse. At K=30%, the average severity of the disease is stated, which means a fairly rapid growth of cancer. With chemotherapy, it can be slowed down and even stopped.

However, K-67 is not the only indicator that is indicated in the medical report. Antibodies are also recorded, to which the corresponding antigens, the type and number of the latter have been identified.

The resulting conclusion is passed by the pathologist to the attending oncologist, who selects the treatment. To evaluate its effectiveness, immunohistochemistry is carried out again after the completion of the therapeutic course.

Video

Read more: Embryo PGD

Photo: © Depositphotos