Dr.Ramesh Hariharan, CEO at Strand Life sciences
One of the main causes of disease and mortality in the world today is still cancer. Since genes are the primary cause of cancer, the relationship between genes and cancer has been most effectively utilized in contemporary oncology, opening new avenues for personalized diagnosis, treatment, and prevention strategies. Even with the fastest-paced scientific advancements which helps us uncover layers of genetic complexity that influence an individual’s susceptibility to various types of cancer, it continues to remain a menace to many people. The following seven factors indicate that genetics raises the risk of cancer:
1. Cancer is a Genetic Disease
At its core, cancer is a genetic disease. Certain genetic variants lead to the uncontrolled cell division that we call cancer. We may be born with such variants, or we may acquire them over our lifetime. An overwhelming majority of genetic variants do not lead to cancer, only a few do.
2. Most Cancers are Sporadic
The majority of genetic variants that cause cancer are acquired over one’s lifetime. This may happen on account of exposure to various environmental factors (e.g., tobacco smoke, radiation, chemicals, and viruses) or even by sheer random chance. Such genetic variants accumulate with age, thus making age and certain environmental exposures the key risk factors. i
3. Some Cancers Have An Inherited Basis
Mutations in the BRCA1 and BRCA2 genes boost a woman’s risk of breast or ovarian cancer manyfold; these mutations also increase a man’s risk of breast, prostate, and pancreatic cancer. These mutations are among the most well-studied genetic variants linked to malignancies. 10 % of people who are born with a genetic mutation makes them even more susceptible to developing breast and ovarian cancers, and a smaller proportion of other cancers, more than the average person.There are several such “germline cancer risk” genes known today (the term germline just means that these genetic variants can be passed down from parents to their children). Understanding the status of these genes can provide valuable insights into an individual’s inherited cancer risk.
4. Screening for Inherited Cancer Risk Can Save Lives
Roughly 2 in a 100 individuals in the general population are born with a risk-conferring genetic variant. While some of these individuals may have a family history of cancer that serves as a warning bell, a majority may have no warning bells. Identifying these individuals and taking preventive action could potentially reduce the number of cancer cases. Indeed, publications estimate that screening every adult woman for genetic variants in the BRCA1/2 genes could prevent 750,000 cancer cases and save 250,000 lives in India. The preventive actions required are laid out, gene by gene, in various medical guidelines and include more frequent surveillance and potential risk reducing surgery.
5. Genome Sequencing Inherited Cancer Risk
For individuals interested in assessing their inherited cancer risk, genome sequencing using what is called Next Generation Sequencing (NGS) is the state of the art. Major technology advancements in the last two decades now ensure that NGS is within affordable range for many in India. However, NGS is a complex process with multiple laboratory and data analysis steps and, therefore it is important to choose a testing organization with a strong reputation and track record of handling the complexity and the numerous corner cases that arise. Strand Life Sciences, with its BreastAssure and Genomic Health Insights tests, is an example.
6. Early Detection of Cancer Potentially Improves Outcomes
Most cancers are sporadic and occur due to genetic variants that we acquire over our lifetimes. When a cancer develops in our body, it often offers no visible signs, and is hard to detect. Therefore, most cancers are detected later in their progression. Publications indicate that the later a cancer is diagnosed in its progression, the lesser are the cure or survival rates. So, early detection can potentially improve outcomes. In particular, detection while the cancer is very locally contained and can be surgically removed offers the best potential for cure.
7. Genetic and Other Tests For Early Detection
Medical guidelines suggest different screening tests for different cancers, starting at various ages and performed at various frequencies. These include mammograms for breast cancer, colonoscopies for colorectal cancer, and low dose CT scans for lung cancer. Many cancers do not have a standard screening method and those that do invariably involve radiation (CT scans) or in-hospital procedures (colonoscopies). Upcoming techniques using sequencing of genetic fragments in the blood offer an alternative to radiation and hospital procedures while covering multiple cancers in one test.
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