Genetic testing is used in a number of different situations. The testing that is most commonly used to detect cancer risk is referred to as predictive gene testing. This test looks for gene mutations which may put an individual at risk of acquiring a disease. Genetic testing is generally recommended for an individual who has a medical family history of a particular disease.
For example, a woman whose sister and mother had breast cancer may be asked to get tested for changes in the BRCA1 & BRCA2 genes (breast cancer genes). But this is not the only reason why genetic testing could be used:
Types of Genetic Testing
- Carrier Testing – This may be used in cases where couples need to know whether they carry any gene mutation for a disorder(s) that could be passed onto their child (e.g.: sickle-cell anaemia, cystic fibrosis)
- Prenatal Testing– May be used in the diagnosis of certain conditions in babies while they are in the mother’s womb ( e.g.: Down syndrome)
- Newborn Testing– This is a very common type of genetic testing. Newborn babies are screened for different inherited conditions including sickle cell disease, cystic fibrosis, phenylketonuria (PKU) etc
- Predictive Testing– If a person has a family history of any genetic condition, getting genetic testing done even before he/she has any symptoms might show if the person is at risk of developing that particular condition
- Preimplantation Testing– This is also referred to as Preimplantation genetic diagnosis and might be used when a couple tries to conceive a child via IVF. The embryos are tested for genetic abnormalities and only ones without any, are implanted inside the woman’s uterus
All these types of genetic testing essentially look for any gene changes that have been passed-on from one generation onto the next. These changes can be found in every single cell in the body. With the exception of the screening tests used for newborns, these tests are primarily used for individuals who have certain diseases which run in their families.
Predictive Genetic Testing
Cancer-related genetic screening tests are typically actioned as predictive genetic tests. These may be used:
- To check if an individual has any gene mutation that is known to up the risk for a particular cancer(s)
- To confirm whether there is any suspected gene mutation in an individual/family
Testing Cancer Cells
In some cases, after an individual is diagnosed with cancer, his/her doctor orders tests that check for gene changes. A sample of the person’s cancer cells is tested and the results can give important information on that individual’s prognosis. At times, it can also help the doctors ascertain whether a particular type of treatment could be useful. These tests check for gene changes in the cancer cells that have been taken from the patient and are very different from the tests that are used to check for inherited cancer risk.
Benefits of Genetic Testing
- Regardless of what situation and condition genetic screening is carried out in, it has now become the one way to mitigate the risk associated with genetically-transmitted diseases, some of which could be very severe or impacting
- It helps in getting a better understanding of a person’s risk for a particular disease
- It has to be understood that genetic testing is not fool-proof ; however, it helps people make more informed decisions about their health
- If the result of genetic screening for an individual turns out to be negative for a disease like cancer, it can go a long way in relieving uncertainty and anxiety
- Similarly, a positive result can help a person make crucial decisions about his/her future. In some cases, a positive result might help in detecting the disease in its initial stages which can make the treatment more effective
Cancer has always been considered to be one of the most deadly diseases in the world and almost 70% of cancer deaths are reported in developing countries (A fifth of these come from India). As researchers conduct more studies about genes and their behavioural patterns, genetic testing will prove to be even more helpful in the prevention of deadly diseases such as cancer.