How your genes contribute to cancer

Cancer is a disease that is ultimately caused by a genetic change called a mutation because all cell functions, that is, cell growth patterns and division, are controlled by normal genes, but when it changes for some reason, it becomes abnormal. Cell division leads to abnormal growth and ultimately cancer.

Genes are all-directed carriers for making proteins that do most of the work in our cells. Certain changes in a gene can cause abnormal growth in cells, which are uncontrolled, rapid, and cancerous. These altered genes are called oncogenes or oncogenes.

In some cases, some oncogenes lead to increased production of proteins that cause cells to grow rapidly and out of control. Others usually result in the production of non-functional forms of proteins that repair cell damage.

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Genetic changes that promote cancer can be inherited from our parents if there are changes in the germ cells of the body (eggs and sperms). These changes, called germline changes, are found in all cells of the offspring.

Carcinogens can cause carcinogenic genetic changes that can be acquired throughout life as a result of errors that occur when cells divide. Carcinogens that damage DNA can be certain chemicals in cigarette smoke or radiation, such as UV light from the sun. Genetic changes that occur after conception are called somatic (or acquired) changes.

There are many types of changes in DNA. Some changes affect only one unit of DNA, called a nucleotide. One nucleotide may be replaced by another, or it may be completely missing. Other changes include larger DNA stretches and may include rearrangement, deletion, or duplication of long DNA stretches.

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The changes may not be in the actual DNA sequence. For example, the addition or deletion of chemical marks on DNA, called epigenetic modifications, can affect whether a gene is “expressed”, that is, whether and how much messenger RNA is produced. (The messenger RNA is then translated to produce the protein encoded by the DNA.)

In general, cancer cells have more genetic changes than normal cells. However, each person’s cancer has its own combination of genetic changes. Some of these changes may be the result of cancer, not the cause. As the cancer continues to grow, further changes occur. Even within the same tumor, cancer cells can show different genetic changes.

Hereditary cancer

Almost 10% of all cancers are due to hereditary genetic mutations.

There are various tests available that can tell if a family member showing signs of such a syndrome has one of these mutations. These tests can also show whether a family member with no obvious illness inherits the same mutation as a family member who has a cancer-related mutation.

Experts should consider genetic testing for cancer risk if they have a personal or family history that suggests a hereditary cancer risk status, but the tests are accurate and predictive for a particular cancer. Is recommended.

Cancers that are not caused by hereditary genetic mutations can occur for non-genetic reasons. For example, the same environmental exposure or lifestyle, such as chewing tobacco, smoking, and alcohol, can cause similar cancers among families.

It is not always the case that all people who have a mutation that predisposes to cancer in their family will inherit the mutation.

This is an example of a gene that can play a role in hereditary cancer syndrome.

The most commonly mutated gene in all cancers is TP53, which produces a protein that suppresses tumor growth. Germline mutations in this gene can also cause Li-Fraumeni syndrome. This is a rare genetic disorder that increases the risk of developing certain cancers.

Hereditary mutations in the BRCA1 and BRCA2 genes are associated with hereditary breast and ovarian cancer syndromes. It is a disorder characterized by an increased lifetime risk of breast and ovarian cancer in women. In addition to breast cancer in men, several other cancers, such as pancreatic and prostate cancer, are associated with this syndrome.

Another gene that produces a protein that suppresses tumor growth is PTEN. Mutations in this gene are associated with Cowden Syndrome, a hereditary disorder that increases the risk of breast, thyroid, endometrial, and other types of cancer.

Genetic testing for mutations that cause hereditary cancer syndrome is usually requested by a human doctor. Some genetic counselors can help people consider the risks, benefits, and limitations of genetic testing in certain situations.

A genetic counselor, doctor, or other genetically trained healthcare professional can help an individual or family member understand their test results and explain the possible effects of the test results on other family members.

How to identify genetic changes in cancer

Lab tests, called DNA sequencing tests, can “read” DNA. By comparing the DNA sequences of cancer cells to the DNA sequences of normal cells such as blood and saliva, scientists can identify genetic changes in cancer cells that may be promoting the growth of an individual’s cancer. I will. This information may be useful in designing specific treatment plans for genetic changes that may ultimately lead to improved overall patient output.

Tumor DNA sequencing can also reveal the presence of hereditary mutations.In fact, in some cases, genetic testing of tumors has shown that the patient’s cancer may be associated with hereditary cancer syndrome that the family was unaware of.

Conclusion

In conclusion, most cancers are caused by some genetic changes, but only 5-10% of these changes are hereditary, the remaining changes are environmental exposure to certain chemicals, radiation exposure, This is due to chronic ingestion of toxic substances such as alcohol. Chewable or smoking tobacco, increased meat in the diet, and a variety of other reasons that can be very well prevented by living a healthy lifestyle and consuming more chemical-free plant-based diets.

There are many changes in genes, but the cause is still unknown. Therefore, you should be aware of the early signs of cancer and immediately receive the advice that cancer can be cured if it is detected early.

(Dr. Vishnu Agarwal is a Surgical Oncology Consultant at Jaslok Hospital and Research in Mumbai. His views are personal.)