Genetic testing is a process that uses molecular biology, biochemistry, and genetics to detect mutations in genes that may lead to cancer. Using genetic profiling, some companies can predict a person’s risk of developing certain types of cancer or hereditary disease before they get sick. It also helps estimate your chance of developing cancer in your lifetime, which can help provide evidence to support preventive measures. Several genetic tests predict a person’s risk of developing or having a certain type of cancer. One way to use such tests is to determine an individual’s specific cancer risks using tumor suppressor genes (TSGs). These genes play an essential role in developing many different types of tumors. Some researchers believe that hereditary (genetic) testing will be necessary for predicting and preventing cancer:
1. Germline testing
This test evaluates an individual’s genetic material (DNA) from all their cells to detect mutations associated with tumor suppressor genes. It determines if a person has an inherited mutation in tumor suppressor genes passed down from one or both parents. It refers to genetic testing on tissue samples from an early-stage human fetus embryo. Germline testing can predict an individual’s risk of developing and passing on cancer genes. For this reason, germline tests are also called predictive genetic tests.
2. Molecular tests
This type of testing examines copies of genes, called messenger RNA, that are made from DNA. These RNAs contain instructions for synthesizing proteins, which are cellular structures and components that carry out a range of cell functions. Molecular tests look for mutations in these instructions in the RNA. A mutation is a defect or variation in a gene. This type of test looks for a genetic change in the region containing instructions for making an RNA molecule.
3. Chromosomal tests
This type of test determines whether the tests analyze whole chromosomes or long DNA lengths passed from parent to child. Chromosomal tests examine the number of chromosomes in a person’s cells to test for abnormal numbers and to look for missing or extra chromosome parts called genes. Chromosomes are the structures that contain all of the DNA in cells. Chromosomal testing is used to show if there is an abnormality in the makeup of a person’s chromosomes.
4. Gene expression tests
These tests are done on breast cancer cells after surgery or biopsy. The test analyzes the amount of RNA made by the tumor cells. Those with a mutation may exhibit abnormal gene expression or changes in how a particular gene behaves. This is important because it can be used to predict which women are at risk for breast cancer.
5. Newborn screening tests
Newborns are screened for certain genetic disorders like down syndrome and cystic fibrosis. These disorders are due to an abnormal number of chromosomes in a baby. The newborn screening tests detect a change or mutation in the genes that help determine the child’s blood type. Scientists are currently developing tests to help detect whether there is a mutation in the gene that causes breast or ovarian cancer.
There is a need for the public to understand that genetic tests are being used to identify genetic defects and inherited cancer. The public must be aware of the limitations of genetic testing for cancer and cancer risk. The tests may give false positives and, in some cases, false negative results, leading to unnecessary treatment or procedures that may do more harm than good.
