Lung cancers begin in the cells lining the parts of the lung including bronchi, bronchioles, or alveoli. The types of lung cancers are as follows:

1. Non-small cell lung cancer (NSCLC) 
2. Small cell lung cancer (SCLC)

Treatment options

Lung cancer is treated in several ways, depending on the type of cancer and its spread. Depending on this, there is numerous treatment options include surgery, chemotherapy, radiation therapy, immunotherapy and targeted therapy. 

Biomarkers

A biomarker is a chemical substance found in body fluids or tissues and its presence is a sign of disease. Biomarkers have a wide range of uses in cancers, including risk assessment, rapid detection of disease, diagnosis, prognosis of treatment response, and disease progression assessment. 

Biomarkers in lung cancer

Identification of a variety of biomarkers was useful in the targeted therapy of patients with lung cancers. There are 12 biomarkers identified so far. The crucial biomarkers that promote cancer cell proliferation and play a significant role in lung cancer are discussed below.

1. Epidermal growth factor receptor (EGFR): It causes cancer cells to produce a protein that causes their rapid proliferation. It is found in 10-15% percent of lung cancers.
2. Anaplastic lymphoma kinase (ALK): It has the potential to be fused to another gene or it may relocate from its original location. ALK positive lung cancer accounts for about 4% of all lung cancers.
3. B-RAF proto-oncogene, serine/threonine kinase (BRAF): This mutation causes the development of BRAF protein, causes cancer cells to proliferate excessively. Such mutations are found in about 4% of lung cancers. 
4. MET proto-oncogene: This gene codes for a protein which signals cancer cells. This accounts 5% of lung cancers.
5. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA): This affects a protein which is vital for cancer cell growth and affects up to 4% of lung cancers.  

Comprehensive genomic profiling (CGP)

CGP is a new approach of genetic testing, ,that uses a single assay to assess hundreds of mutations and alterations in hundreds of genes and relevant cancer biomarkers for therapy guidance. Changes in these biomarkers lead to lung cancers and can be identified by genetic testing. Patients were assigned to targeted therapies based on these profiling results. It is unique to each patient assists in precision medicine.

Immunotherapy markers

The immunotherapy approach targets immune checkpoint pathways, which includes the blockade of the inhibitory receptors. These checkpoints are inhibitory pathways regulating immune responses. Immunotherapy markers in lung cancer are Cytotoxic T-lymphocyte-associated antigen 4 and Programmed death-ligand 1 receptor. These are mainly expressed on immune cells. Many other checkpoint molecules have been identified and are currently being evaluated as potential targets for cancer immunotherapy. 

Role of biomarkers in cancer immunotherapy

Immunotherapy is an effective oncology treatment that utilizes the body’s own natural defence system to combat cancer. Because certain cancer cells exhibit characteristics that are similar to those of healthy cells, the immune system is unable to distinguish between healthy and cancer cells. Immunotherapy is thought to function by strengthening the immune system so that it can target cancer cells and stop them from spreading. To maximise therapeutic benefit, predictive biomarkers for immunotherapy must be established.

Role of biomarkers in improving clinical outcomes 

Biomarker testing has resulted in the development of targeted treatments. The targeted anticancer therapies along with new immunotherapy methods, has resulted in new personalized therapy approach. There has been a trend toward individualising therapy for each patient based on the expression of biomarkers. 

Biomarker testing allows doctors the most in-depth knowledge on the cancers and immune systems of the patient to come up with particular medicine for a particular patient (Personalized medicine) as each patient has a unique pattern of biomarkers. This has aided in maximising the quality of life by focusing on the right targets. Personalized medicine is based on each patient’s unique genetic composition, which overcomes the limits of standard chemotherapy regimens with more effectiveness. As it targets on a particular biomarker, the predictable side effects will be substantially low with reduced failure rates, thus improving survival and response rates.

Precision medicine

Precision medicine (Personalized medicine) is a type of medicine that uses data from a person’s own genes or proteins through genetic testing to prevent, diagnose, and treat a disease. Biomarker tests are vital in the selection of precision medicine as part of targeted personalized therapy that particularly targets on cancer cells with fewest side effects. This has advanced the cancer treatment with personalised medicines that lead to improved patient outcomes.