Lung Cancer Biomarkers - An Overview

Introduction

To diagnose cancer, clinicians use biomarker testing, also known as molecular testing or tumor marker testing, to study tumor tissue from a biopsy or blood sample. Cancer patients have elevated biomarkers in their blood, urine, or tissues. DNA mutations, alterations, and patterns in tumors are various biomarkers.

What Is a Lung Cancer Biomarker?

Lung cancer biomarkers are proteins, hormones, or DNA fragments (deoxyribonucleic acid) that are either secreted by cancerous cells or produced by the body in response to cancer. Biomarker tests may be performed by a medical practitioner or a healthcare expert to detect the presence of a specific biomarker in a person's body. Historically, a uniform treatment approach was employed for all individuals diagnosed with lung cancer. Currently, therapeutic interventions are specifically tailored to individuals based on their biomarkers. Biomarkers play a crucial role in prognosticating optimal therapy modalities or care for cancer patients; they can serve as indicators of treatment efficacy.

Medical professionals employ it to facilitate the diagnosis of cancer and determine its potential rate of progression. Although biomarkers are present for small-cell lung cancer, their predominant application lies in the diagnosis and management of non-small cell lung cancer (NSCLC).

Why Can Biomarker Testing Benefit Lung Cancer Patients?

• Some lung cancers have specific gene changes (mutations).

• Targeted medicines are designed to attack these changes in cancer cells.

• It can slow the tumor growth.

• Doctors often do biomarker tests to find the right targeted treatment.

• Targeted therapy usually causes fewer side effects because it mainly affects cancer cells.

When Does Biomarker Testing Accompany Lung Cancer Treatment?

• Biomarker testing is most useful for people with advanced (stage IV) non-squamous NSCLC.

• Doctors may use broad tests, such as next-generation sequencing (NGS), to assess multiple biomarkers simultaneously.

• Some people with advanced squamous lung cancer may also need testing, especially if they have little or no smoking history or mixed tumor types.

• Biomarker testing may also be done in some early-stage lung cancer cases.

• Doctors often check for EGFR (epidermal growth factor receptor) and ALK (anaplastic lymphoma kinase) gene changes because targeted treatments are available for them.

• Some oncologists also consider testing for stage I to III NSCLC when planning treatment.

• However, biomarker testing is not yet standard for all lung cancers below stage IV.

What Are the Classifications of Biomarkers?

Lung cancer biomarkers are mutations caused by gene alterations or rearrangements that encourage cancer cell development.

• Immune Response Biomarkers: These biomarkers indicate how effectively immunotherapy will work for a given malignancy. NSCLC gene mutation biomarkers include:

• Tumor Protein p53 (TP53): The most prevalent mutation in NSCLC is TP53. It is seen in approximately 50% of patients with NSCLC.

• KRAS: The second most prevalent mutation in NSCLC is KRAS. The KRAS mutation is found in approximately 30% of patients with NSCLC. The serine/threonine kinase 11 (STK11) mutation is frequently found in conjunction with it.

• EGFR: The EGFR mutation causes the creation of the EGFR protein, which causes cancer cells to grow excessively. There are several EGFR mutations, the most frequent being EGFR exon 19 deletion and EGFR exon 21 L858R point mutations.

• Anaplastic Lymphoma Kinase: The ALK gene can be relocated or fused to another gene, such as the echinoderm microtubule-associated protein-like 4 (EML4) gene. ALK-positive lung cancer affects those around it with NSCLC.

• MET Gene and MET Exon 14(METex14): The MET gene codes for the MET protein, which transmits growth signals to the cancer. Exon 14 skipping is a defect that hinders the degradation of a certain type of MET protein, which results in extra protein in the body.

• PIK3CA: The PIK3CA mutation affects the p110 alpha protein. This protein is required for lung cancer cell proliferation and survival.

• BRAF: This mutation causes the creation of an aberrant protein, which causes cancer cells to grow excessively. BRAF mutations are found in persons with NSCLC.

• Human Epidermal Growth Factor Receptor 2 (HER2): The HER2 gene mutation delivers signals that promote tumor growth. Breast and ovarian cancers are also associated with HER2 gene alterations. HER2 gene mutations are found in one to four percent of persons with NSCLC.

• ROS1: This gene may be misplaced or fused to a portion of another gene. ROS1 is mutated in one to two percent of NSCLC patients.

• RET: The RET gene may be mispositioned or fused to another gene. This mutation is found in one to two percent of persons with NSCLC.

• NTRK (Neurotrophic Tyrosine Receptor Kinase): The NTRK gene can combine with another gene, resulting in uncontrolled cell proliferation. This gene alteration affects approximately 1% of individuals with NSCLC.

Non-small cell lung cancer is associated with many biomarkers that are indicative of the immune response. Programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are membrane-bound proteins expressed on T cells, a subset of healthy white blood cells. Furthermore, these receptors are present at higher levels on certain cancer cells. They function as an inhibitory mechanism that impedes the immune system's assault on cancerous cells. Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a protein that plays an essential role in regulating the immune response. Additionally, this protein is found on the surface of T cells. It hinders the immune system's ability to respond to malignancy.

What Are the Various Applications of Biomarker Testing?

Biomarker testing provides healthcare professionals with additional insights into tumor characteristics. Individuals diagnosed with non-small cell lung cancer should undergo these tests. The specimen is sent to a laboratory or testing facility to examine DNA alterations and quantify certain protein levels. Several methods exist for identifying biomarkers associated with lung cancer.

• Next-generation sequencing (NGS) is a test that analyzes a tissue or blood sample using a specialized machine to detect multiple cancer-related genes simultaneously.

• Fluorescence in situ hybridization (FISH) uses a fluorescent dye to detect specific cancer genes within cells.

• Immunohistochemistry (IHC) is a widely employed staining technique in biomedical research and clinical diagnostics. It involves the use of specific antibodies, proteins that bind target biomarkers, to precisely identify and localize them within a given tissue sample.

Conclusion:

Lung cancer biomarkers are helpful tests that give important information about the cancer. They help doctors understand the type of lung cancer and choose the most suitable treatment for each patient. Biomarker testing can also help avoid treatments that may not work.

With better testing methods, many patients can now receive more targeted and effective therapies. Therefore, biomarker testing plays an important role in improving treatment decisions and patient care in lung cancer. If you or your loved ones have similar cancer issues, consult a cancer doctor.

Key Takeaways:

• Lung cancer biomarkers are specific genes or proteins found in cancer cells that help doctors better understand the cancer.

• Biomarker testing helps doctors choose the most suitable and targeted treatment.

• It is commonly used in patients with advanced lung cancer to guide therapy.

• Finding the right biomarker can improve treatment results and patient care.