▶ Lee Soo-hyun, professor of oncology and hematology at Korea University Anam Hospital
Lee Soo-hyun, professor of oncology and hematology at Korea University Anam Hospital, said, “With the development of gene mutation diagnosis methods, the diagnosis rate of ‘hereditary cancer’, which accounts for 10-15% of all cancers, is increasing. .” [고려대 안암병원 제공]
The disease that Koreans worry about the most is cancer. This is because it is the leading cause of death in Korea. However, some people can easily come into contact with cancer due to genetic causes due to lack of gene repair ability. Cancers that develop in this way are called ‘hereditary cancers’. It is estimated that it is 5-10% of all cancer patients. I met Lee Soo-hyun, professor of oncology and hematology at Korea University Anam Hospital. Professor Lee said, “If you are a cancer patient with a mutated gene, the prevention and treatment of cancer should proceed differently to normal cancer patients.”
– What is hereditary cancer?
Cancer is a condition where genetic mutations that have occurred within cells for some reason accumulate and multiply indefinitely. Genes have the ability to repair themselves even if they are damaged, but when a mutation occurs in the repair gene, normal cells are continuously exposed to the risk of cancer, and the damaged gene cannot be repaired. . This is called ‘hereditary cancer’.
Hereditary cancers develop very quickly and can appear at a young age. It usually takes 10 to 15 years for colon polyps to turn into cancer. However, if there is a specific genetic mutation, it can turn into a malignant tumor even after 2 to 3 years.
– Does cancer appear when a gene mutation occurs?
Not so. If there are specific gene mutations such as MLH1·MSH2·MSH6·PNS2, there is a high probability that different types of cancers associated with the gene mutation will occur, rather than specific cancers. For example, if you have a genetic mutation called MSH2 in your 30s, the risk of developing bladder or kidney cancer by the time you turn 70 increases by more than 40%.
In addition, if there is a germ cell mutation in a specific location of the APC tumor suppressor gene, a familial polyp syndrome where more than 100 polyps occur, and in this case, the risk of colorectal cancer as high as 90%. A particular mutation in the BRCA1 gene found in American film star Angelina Jolie increases the risk of breast cancer by 65% and the risk of ovarian cancer by 75%. In this case, it is important to check for genetic mutations through genetic testing.
– If parents get cancer, do their children get the same cancer?
A predisposition to cancer is often inherited from parents. Even if not, certain genes are damaged and cause cancer. In particular, since family members share lifestyle habits, it is possible to get the same cancer even if there is no genetic abnormality. This is the case when fathers who smoke and family members who smoke secondhand smoke are at high risk of lung cancer.
– If someone in your family has cancer, should you get tested as a preventative measure?
Not necessarily. If a close family member (parents, children, siblings) diagnosed with cancer is diagnosed with cancer under the age of 50, they need to have a genetic test. If your grandfather was diagnosed with cancer at the age of 80, there is no need for genetic cancer screening.
Additionally, NGS genetic test results are only meaningful when interpreted in conjunction with the clinical situation. Genes alone are not diagnostic because they have to be compared with the average health information of healthy people and combined with family history and genetic testing.
-How do genetic tests work?
It can be done in any tissue where DNA can be identified in our body, but blood tests have the highest sensitivity and accuracy. In the past, a blood test was used to test for mutations in one specific gene, but with the development of technology, dozens of genes known to be involved in the development of hereditary cancer can be tested at once with ‘Next Generation Sequencing (NGS). ‘ gene panel test
-Who should have NGS genetic testing?
First of all, you should be careful if you are diagnosed with cancer younger than the average age of onset. Hereditary cancer should be suspected if breast cancer occurs under the age of 40 and colorectal cancer occurs under the age of 50. Second, when cancer occurs several times in one person with a difference in time. Thirdly, if there are many patients with the same type of cancer in your family, if invasive polyposis (Lynch syndrome, familial polyposis) is found at endoscopy, or if genetic cancer is confirmed in your immediate family or siblings, you need to visit a ‘hereditary cancer clinic’ for a consultation. .
If a mutant gene is found, there is a 50% chance that the child will also have the genetic mutation, so close family members need additional testing. In particular, it is good to have genetic tests more than 10 years earlier than patients who were diagnosed with cancer at the youngest age in their family.
Daeik Kwon Medical Specialist Reporter >
