Introduction
Globally, lung cancer is the primary cause of death associated with cancer. The two main causes of lung cancer are smoking and air pollution. But, experts have recently discovered that genetic factors also contribute to the development of lung cancer. Both smokers and never-smokers are more susceptible to lung cancer if there is a family history of the disease.
What Is Lung Cancer?
The illness known as lung cancer occurs when specific lung cells develop inappropriately and multiply excessively, resulting in the formation of a cancerous growth. Early in its development, lung cancer might not exhibit any symptoms. Chest discomfort, persistent coughing, blood in the mucus, difficulties with breathing, difficulty speaking or swallowing, decreased appetite and reduction in weight, and exhaustion are some of the symptoms of lung cancer. Adults between the ages of 60 and 70 are most commonly affected by lung cancer. The majority of individuals who acquire lung cancer have a record of prolonged tobacco use, yet the illness can strike even people who never used tobacco products.
What Is Genetics?
Exploring genes and attempting to understand their functions is the field of genetics. Living things acquire characteristics or qualities from their predecessors through genes; for instance, children typically resemble their biological parents due to gene inheritance. The goal of genetics is to determine which features are inherited and to provide an explanation for how these qualities are handed down across the generations.
What Are Genes?
The basic components of the human body are genes. Some genes provide instructions on how to create proteins. The function of protein is to determine the physical nature of a person, for instance, the color of the eye or hair. The function of genes is to send signals to control cells’ division and proliferation. The human body contains between 20,000 and 25,000 genes.
What Is the Link Between Genes and Lung Cancer?
A smaller percentage of lung cancer is linked to genes. One class of genes called oncogenes promotes cell division and growth. Tumor suppressor genes cause cells to either cease proliferating or die off when they are no longer needed. Cancer develops when cells begin to grow and replicate excessively due to malfunctions or the absence of any of the signals sent by genes. Mutation or changes in the genes make them send improper signals. Specific forms of lung cancer are more likely to be caused by genes. For instance, particular genetic modifications are present in roughly 60 percent of patients with lung adenocarcinomas.
Cancer has been demonstrated to be initiated by mutations in oncogenes and tumor suppressor genes. Thus, it is important to look into these genes to analyze the biological processes behind cancer. Numerous tumor suppressor genes and oncogenes have been linked to lung cancer.
1. K-RAS Genes (Kirsten Rat Sarcoma Viral Oncogene Homologue):
The RAS genes were among the earliest known oncogenes, categorized as H-RAS, K-RAS, and N-RAS. A G-protein formed by K-RAS governs signaling pathways that affect cell survival, growth, and division. Mutations (changes) in the K-RAS gene cause lung adenocarcinoma in 25 to 30 percent of the cases.
2. EGFR:
Epidermal growth factor receptor (EGFR) is a protein present on the cell surface. It controls cell growth and division. EGFR is a member of avian erythroblastosis oncogene B (ERBB). It also includes ERBB 2, ERBB, and ERBB 4. Mutations in EGFR or ERBB 1 have been linked to 43 to 89 percent of non-small cell lung cancer. There are two types of EGFR-targeting medications now on the market: monoclonal anti-EGFR antibodies like Cetuximab and small-molecule EGFR tyrosine kinase inhibitors (TKI) like Gefitinib and Erlotinib.
3. RAF Genes:
RAF(rapidly accelerated fibrosarcoma) includes three forms of oncogenes, namely A-RAF, B-RAF, and RAF-1. B-RAF oncogene mutation is identified in six to eight percent of non-small cell lung cancer. It results in over 90,000 annual deaths worldwide. Whether or not a woman has ever smoked, B-RAF mutations are common in lung adenocarcinoma patients.
4. HER2 (Human Epidermal Growth Factor Receptor 2):
Like EGFR, HER2 is a receptor tyrosine kinase in the ERBB family. Two to four percent of non-small cell lung cancer cases have been found to contain HER2 changes. Adenocarcinoma is more likely to have HER2 alterations than other forms of lung cancer, and these mutations are more common in Asian women patients who have never used tobacco.
5. EML4 and ALK Genes:
Mutations in EML4 (echinoderm microtubule-associated protein-like 4) and ALK (anaplastic lymphoma kinase) genes are linked to non-small cell lung cancer (NSCLC) in about three to seven percent of cases. The newest therapeutic targets for NSCLC treatment are the fusion protein anaplastic lymphoma kinase (ALK) and echinoderm microtubule-associated protein-like 4 (EML4).
How Are Lung Cancers With Genetic Alterations Screened and Treated?
There is still much that researchers need to discover regarding the genetic causes of cancer of the lungs. EGFR, KRAS, ALK, and BRAF (v-Raf murine sarcoma viral oncogene homolog B1) mutations are linked to lung cancer. These mutations are acquired and are not present in healthy cells. Therefore, they cannot be found before lung cancer manifests.
- Genetic Testing: The choice of targeted medicines for lung cancer treatment is one area in which genetic testing can be beneficial. This method involves analyzing lung cancer samples for genetic abnormalities and then applying a cancer treatment that targets and kills the malignant cells with the detected gene mutation.
- Targeted Therapy: These medications mostly spare normal cells from harm while targeting and eliminating cancer cells with certain curable abnormalities. As a result, side effects from targeted medicines are frequently reduced.
Among the specific medications for EGFR-mutant non-small cell lung cancer are:
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Afatinib.
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Gefitinib.
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Osimertinib.
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Erlotinib.
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Dacomitinib.
Targeted medications for non-small cell lung cancer with an ALK mutation include:
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Alectinib.
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Brigadinib.
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Lorlatinib.
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Crizotinib.
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Ceritinib.
Conclusion
The types of lung cancer that affect individuals who do not smoke are different from those who have the habit of smoking. These cancers appear to develop at a younger age and show genetic mutation. These changes are different from the genetic changes found in cancers of people who smoke. These gene alterations may be able to direct treatment in some situations. Research on lung cancer in families may contribute to a better understanding of the underlying causes and processes of lung cancer. It will also help to determine the biomarkers for early disease identification and treatment.
