What is Liquid Biopsy? How is Liquid Biopsy Done?

Cancer; Today, it is one of the most important health problems that threaten human health and for which intense efforts are made to solve. Although various diagnostic and treatment methods have been used to date, an effective method for eliminating cancer has still not been determined. For this reason, a lot of research is being carried out on cancer internationally, and many different technologies are used in terms of diagnosis and treatment methods. One of these methods is liquid biopsy.

What is Liquid Biopsy?

By its nature, cancer primarily occurs as a result of certain deteriorations in healthy cells of the body under the influence of various genetic and environmental factors. Cells whose biological structure is disrupted not only proliferate uncontrollably, but also act contrary to the physiological functioning of the body and acquire an unnatural tissue structure. Over time, the proliferating cells form masses called tumors and acquire a vascular structure of their own. At this point, cancer cells acquire new properties and have the opportunity to spread to other parts of the body and begin to move into the bloodstream and take part in the blood circulation.

Here, these cancer cells or the DNA of these cells in the circulation; The process of detecting and examining blood samples taken from patients is called liquid or liquid biopsy. Similar to routine blood tests based on measuring different biochemical substances in the blood, various methods are used to detect cancer cells in a certain amount of blood samples taken from patients, and the identified cancer cells can be typed with additional methods.

In the presence of tumor tissue, cancer cells must be demonstrated in pathological examination in order to make a definitive diagnosis of cancer. For this purpose, the frequently used method is to remove all or part of the tumor tissue, send it for pathological examination, and during this examination, cancer cells are isolated and detected by various methods. This entire method is called tissue biopsy and histopathological examination.

Tissue biopsy can be performed directly with various equipment under clinical conditions, or by removing the tumor during various imaging procedures such as endoscopy or during surgery. In addition, with another method called needle aspiration biopsy, tissue content is removed with the help of a needle, especially in tumors with cystic structure, and cancer cells are detected by cytological examination. The difference here is that although cancer cells can be shown from the tissue content obtained, the tissue structure cannot be preserved. Liquid biopsy is different from these two methods. Thanks to its various advantages, it provides the physician with detailed and valuable information that cannot be obtained with the other two methods, while providing ease of application and comfort to the patient.

What is the Purpose of Liquid Biopsy?

The purposes of liquid biopsy application can be defined as follows:

• First of all, in order to perform a tissue biopsy or needle biopsy, tumor tissue must be present and access to this tissue must be possible. For this reason, it makes it possible to detect cancer in its advanced stages when it forms a tumor mass; It is also difficult to implement. Additionally, serious interventions such as surgery may be needed. On the other hand, liquid biopsy enables the detection of cancer cells at an early stage, even before the cancer has formed a tumor mass, after an ordinary and simple intervention such as routine blood tests.
• In early stage cancer disease, where cancer cells cannot yet be detected, it provides very valuable information in terms of diagnosis and treatment planning by isolating only cancer DNA in the bloodstream.
• By typing the cancer cells obtained, it allows more effective treatment methods to be applied.
• It helps to make the right drug choice according to the detected biological characteristics of the cancer.
• It allows measuring the effectiveness of the applied treatment.

When is Liquid Biopsy Performed?

Liquid biopsy is a preferred method, especially in cases where normal tissue biopsy cannot be applied, the existing cancer disease occurs in another body part, or the information obtained by tissue biopsy is not sufficient for diagnosis and treatment planning. Liquid biopsy is a very important method in diagnosis and treatment decisions because it is easily reproducible and provides valuable genetic and biochemical data.

Studies have shown that liquid biopsy is especially useful in the following types of cancer:

• breast cancer
• Lung cancer
• gastrointestinal cancer
• pancreatic cancer
• Cervix, Endometrium, Ovarian and tubal cancers
• kidney cancer
• bladder cancer
• Melanoma
• brain tumors
• testicular tumors
• Leukemia and Lymphomas (blood cancer)
• Other rare epithelial tumors

It can be used in the diagnosis of various types of cancer; In cancers that are at risk of recurrence after treatment, liquid biopsy can be used to show whether there is a recurrence at an early stage. It also provides useful information in planning the treatment of these diseases and evaluating the response to treatment.

How is Liquid Biopsy Done?

Liquid biopsy; It is performed by taking a certain amount of blood sample from the patient, as in routine blood tests. The following parameters are examined in the blood sample taken to obtain the necessary data for diagnosis and treatment:

Detection of circulating cancer cells: Small amounts of cancer cells that enter the bloodstream are isolated by various methods. The various properties of the resulting cell can be analyzed using detailed techniques for the purpose.

Detection of DNA samples of cancer cells: Since cancer cells that enter the bloodstream continue to divide rapidly, they may break down periodically and transfer their contents to the blood fluid. One of the most important ingredients in this content is the DNA sample of the cancer cell. By isolating the DNA of the cancer cell from the blood obtained by liquid biopsy and performing many purposeful analyses, in addition to cancer diagnosis, very valuable information is obtained such as cancer typing, treatment planning according to DNA characteristics, and determination and follow-up of the response to treatment.

Many structural and functional cellular changes specific to cancerous cells can be detected and investigated in depth from circulating tumor cells (CTC) in the circulating blood or from the DNA shed from these cells, that is, from the material obtained by liquid biopsy.

What are the Benefits of Liquid Biopsy?

There are some advantages provided by liquid biopsy application. It is possible to list these advantages as follows:

• Compared to serious interventions and invasive techniques used in tissue biopsy; Liquid biopsy is simple and involves very little intervention; But it is an effective application.
• It is a cheaper procedure than tissue biopsy and pathological examination.
• It provides valuable information about the genetic and biological background of the tumor and is very useful in both determining the method used in treatment and evaluating the response to treatment.
• Since it can be easily applied and repeated, it makes it possible to follow changes in reactions such as drug resistance in cancer cells during the treatment period. Since tissue biopsy is only for diagnosis, it cannot offer a similar benefit.
• Since the sample obtained from tissue biopsy can only be examined after going through special chemical processes, it is not suitable for examining the genetic structure of the cancer cell. On the other hand, DNA of cancer cells in the blood can be detected and examined in detail with liquid biopsy.
• While pathological examination of tissue biopsy may take weeks, the result of liquid biopsy can be determined in a much shorter time.

What is the Future of Liquid Biopsy?

Genetic studies and gene therapy are among the most popular research topics today. Since the basis of cancer is genetically related, advances in research on this subject are also breaking new ground in cancer diagnosis and treatment.

It can be said that liquid biopsy will gain more importance in the light of current genetic research. Because, with the result of liquid biopsy, the gene map of cancer cells in the bloodstream can be obtained. In this way, possible target regions that can be targeted in gene therapy can be identified and it may be possible to completely eliminate cancer with an effective gene therapy. Likewise, significant progress can be made in the treatment of cancer by eliminating the resistance mechanisms that cancer has developed against the treatment methods used.

If you would like to get more detailed information about liquid biopsy, you can contact our hospital to get help from specialist physicians.