Biomarkers are key in deciding on subsequent treatment, especially in oncological diseases.
Biomarkers can be extracted and analyzed from various biological materials such as blood, urine, saliva as well as various tissues, including tumor tissue.
Tumor markers in oncology can be different types of RNA molecules, proteins, cellular metabolites and organic materials, as well as different variants in the DNA structure. In recent years, the- DNA-based biomarkers have gained a lot of traction, as well as protein ones.
Lung cancer is not 'one disease': there are different types and each type of lung cancer is different. It is important to know the exact type of lung cancer, because then there is a better idea of the course of the disease and its treatment. Biomarker tests indicate whether a patient will benefit from a particular treatment and which treatment is best for them.
Biomarkers are "clues" in cells or in the body, which tell us something about the behavior and type of cancer. Biomarkers are used, to analyze what type of cancer it is and which treatment has the best chance of success. Their use increases the chance of successful treatment.
Biomarker testing involves laboratory testing, using samples of a patient's tumor tissue or body fluids such as blood or urine, looking for the presence of known mutations in the tumor cells. Test results are interpreted by medical oncologists, so they can determine the best treatment for their patients. In lung cancer, biomarkers are often 'driver mutations', ie. genetic changes, which cause cells to grow uncontrollably. Common mutations in lung cancer are: KRAS, EGFR, BRAF, ALK, MET, ROS-1, NTRK.
By their nature, biomarkers can be divided into 3 large categories: diagnostic, prognostic and predictive.
- Diagnostics are used to make the specific diagnosis. Yeah, they're like that: BCR- ABL, JAK2 mutations, etc.
- Prognostic biomarkers provide information about how a disease will progress and whether the patient's prognosis is good or not so good. Such are, for example, BRAF mutations in patients with colorectal cancer.
- Predictive biomarkers are these, that give us information, whether the patient will respond to a given therapy. For example, certain variants in the EGFR gene indicate whether or not the patient is suitable for targeted therapy.
Biomarkers are used in different stages of the development of the patient's disease. For example, some biomarkers could be used to make a diagnosis, others to choose therapy, third – to track the disease or how a particular therapy affects the specific cancer education.
The most- predictive genetic biomarkers have great application in breast and ovarian cancer patients, colorectal carcinoma, as well as non-small cell lung cancer.
In patients with breast and ovarian cancer, the mutational status of BRCA1/2 genes is relevant for the choice of targeted therapy. Targeted therapy in patients with colorectal carcinoma is determined by RAS/RAF mutational status, while MSI (microsatellite instability) has implications for immunotherapy. In patients with non-small cell lung carcinoma, PDL expression is the biomarker that indicates whether or not they are suitable for immunotherapy. EGFR is used for targeted therapy in these patients, ALK, ROS1, BRAF.
Liquid biopsies are a variant of tissue biopsies. With them, unlike conventional biopsy, patient's venous blood is used. When tumor cells die, they release tumor DNA into the bloodstream. Liquid biopsies are an analysis of these items. the sun. "free circulating tumor DNA". Liquid biopsies are a powerful tool for disease monitoring, are also suitable in patients, in which the biopsy material was exhausted. Another advantage is, that they provide a representative sample of the tumor genome, as all tumor cells shed DNA into the blood.
A frequently asked question is when to test biomarkers, how long the analyzes take. In the first place is the attending physician. He judges, when and which biomarkers are needed by the patient. The relationship doctor, patient, geneticist is narrow and two-way. Depending on the biomarkers, the time to issue a result also depends. Po- complex analyzes such as BRCA1/2 take up to 45 days, others like EGFR genotyping take up to 7 working days.
The results are read by the attending physician.
WHAT ARE BIOMARKERS AND HOW THEY ARE USED FOR CANCER DIAGNOSIS AND TREATMENT?
Interview with geneticist Stoyan Bichev
How cancer biomarkers are used in cancer treatment – the medical point of view. Interview with medical oncologist Assoc. Zhelyazko Arabadzhiev
