EGFR protein helps cells to grow and divide (increase in number). Mutations in EGFR exon 20 involve a specific site of the EGFR gene called exon 20 (a region of the EGFR gene which contains part of the genetic code necessary for the formation of the EGFR protein).
Mutations are alterations or changes in the sequence of DNA (genetic material). They can be seen as a change in the DNA code sequence. Normal codes are necessary for the proper functioning of cells and tissues in the body. The occurrence of mutations can cause several health problems. In addition, mutations can affect the action of a drug against a particular disease. Certain mutations can also be favorable. Such mutations provide mechanisms to better adapt to the changing environment (evolution). Mutations can cause cells to multiply out of control, leading to cancer. With advancements in medical science and technology, new treatment options are emerging that target and destroy cancer cells with little or no damage to normal or healthy cells. Mutations in cancer cells can give them benefits by facilitating the progression and spread (metastasis) of cancer. Conversely, mutations can provide treatment benefits as they can create certain microscopic structural changes in cancer cells. These structural changes contribute to the targeted delivery of drugs to cancer cells. This means that the medicine can go and attach itself to the cancer cell and kill it.
what is a EGFR mutation?
Mutations can cause changes in proteins on the surface of cells if they affect the gene encoding a surface protein. One of these proteins is called the epidermal growth factor receptor (EGFR). This protein is most commonly found on skin cells, although it can be found anywhere in the body. The function of EGFR protein is to help cells grow and divide (increase in number). EGFR protein is produced by information provided by the gene EGFR.
Normally, this gene is regulated, which means that there is a switch present in the cell to turn it on when cell growth and division is needed and turn it off when it is not needed. In some types of cancer, such as EGFR-positive non-small cell lung cancer (NSCLC), a mutation in the gene EGFR causes the EGFR protein to remain permanently in the “on” position. NSLC is the most common variety of lung cancer accounting for 80 to 85 percent of cases. The other variety is called small cell lung cancer and represents the rest of the lung cancer cases.
The mutation EGFR causes uncontrolled cell growth (cancer). The abnormal gene EGFR is therefore a type of tumor marker or biomarker that can be detected by laboratory tests. Tumor cells carrying the abnormal gene EGFR are called EGFR-positive cancer cells. This protein was the first tumor marker identified for the targeted treatment of EGFR-positive lung cancer.
EGFR-positive lung cancer is more commonly seen in patients with
- People who have never smoked or smoked a little
- People with a type of NSCLC cancer called lung adenocarcinoma
- Young adults with lung cancer. About 50% of lung cancers seen in young adults are positive for EGFR mutations.
- In people of Asian or East Asian descent
The mutations EGFR can be tested by doing a genetic lab test on a sample of cancerous tissue taken from the lung (a biopsy). A biopsy is the most accurate way to look for mutations EGFR. Doctors can detect mutations inEGFR by taking blood samples that may contain tumor cells excreted by the lungs. This is called a liquid biopsy.
what is a EGFR mutation of exon 20?
Various types of mutations can occur in the epidermal growth factor receptor gene (EGFR) depending on the site involved in the gene. The gene EGFR has several sections (expressed as numbers) called exons. Mutations can occur on any of these exons. The mutations EGFR the most common include missing genetic material (deletion) on exon 19 (19-del) or damage to exon 21 (21-L858R). These two mutations are responsible for about 85% of mutations inEGFR seen in lung cancer. Exon 20 mutations EGFR involve a specific gene site EGFR called exon 20 (region of the EGFR which contains part of the genetic code necessary for the formation of the EGFR protein).
Why know the type of a EGFR significant change?
Know the type of mutation in the epidermal growth factor receptor gene (EGFR) is important in determining treatment for non-small cell lung cancer (NSLC). For example, the deletion EGFR 19 and point transfers EGFR L858R respond to targeted therapies called tyrosine kinase inhibitors (TKIs). The choice of drug may vary depending on the specific mutation. These drugs include
However, cancer with mutations in exon 20 EGFR does not respond to ITKs.
There are other drugs that can be used in cancer with an exon 20 mutation with more success. One of these examples is the drug Rybrevant (amivantamab). It is a monoclonal antibody (a laboratory version of a specific protein in the immune system). It targets two proteins that help cancer cells to grow: EGFR and MET.
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Medical examination on 06/18/21
Medscape: “Genetics of Non-Small Cell Lung Cancer”. https://emedicine.medscape.com/article/1689988-overview
American Lung Association: “EGFR and Lung Cancer”. https://www.lung.org/lung-health-diseases/lung-disease-lookup/lung-cancer/learn-about-lung-cancer/how-is-lung-cancer-diagnosed/lung-cancer-tumor- test / egfr