The Epidermal Growth Factor Receptor, or EGFR, is a protein on the surface of many cells. It acts like a receiver for growth signals from outside the cell. When these signals bind to EGFR, they trigger events involved in normal cellular processes.
EGFR’s Role in the Body
Normally, EGFR regulates cell growth, division, and repair. When a growth factor connects with EGFR, it activates a pathway telling the cell to multiply or fix damaged components. This process is fundamental for maintaining healthy tissues and organs.
If EGFR becomes overactive or malfunctions, it continuously sends signals for cell growth, even without growth factors. This uncontrolled signaling leads to cells dividing excessively. Such unregulated cell proliferation is a hallmark of many cancers.
Understanding EGFR Mutations
An EGFR mutation is a change in the EGFR gene’s genetic code, altering the EGFR protein’s structure and behavior. These alterations often cause the EGFR protein to be constantly “on,” sending continuous growth signals regardless of external cues. This persistent activation drives uncontrolled cell growth and division, contributing to cancer development.
EGFR mutations are particularly relevant in certain cancers, notably non-small cell lung cancer (NSCLC). Deletions in exon 19 and a point mutation (L858R) in exon 21 are common EGFR mutations, accounting for 85-90% of those found in NSCLC. While “81 mutation” might appear in a report, it often refers to a mutation’s location or characteristic influencing protein behavior.
Detecting EGFR Mutations
Identifying EGFR mutations is standard in cancer diagnosis, particularly for non-small cell lung cancer. One common method is a tissue biopsy, where a tumor sample is removed and analyzed. This sample provides genetic material for screening for specific EGFR gene alterations.
Newer techniques, like liquid biopsies, offer a less invasive alternative. These tests analyze blood samples for circulating tumor DNA (ctDNA), DNA fragments shed by cancer cells. Both tissue and liquid biopsies help determine if a cancer harbors an EGFR mutation, guiding treatment decisions.
Targeted Treatments for EGFR-Mutated Cancers
The discovery of EGFR mutations changed cancer treatment, enabling targeted therapies. These specialized drugs, tyrosine kinase inhibitors (TKIs), block the mutated EGFR protein’s activity. By inhibiting this overactive protein, TKIs slow or stop the growth of cancer cells dependent on the mutated EGFR pathway.
Unlike traditional chemotherapy, which broadly attacks rapidly dividing cells, targeted therapies precisely focus on the cancer’s genetic drivers. For patients with EGFR mutations, TKIs show significant efficacy, leading to higher objective response rates and longer progression-free survival compared to conventional chemotherapy. This personalized strategy results in fewer side effects, as drugs primarily affect cancer cells while sparing healthy cells.