Health

Why do so many people in my family get cancer? – VnExpress


Some families with two or three generations of cancer may be exposed to some risk, but most are due to inherited genetic mutations.

Cancer is a common disease. Many families have one or several members with cancer, possibly due to common behaviors or exposure to factors that increase the risk of disease such as smoking. Cancer risk may also be found in some families with obesity.

In some cases, cancer is caused by an abnormal gene that is passed down from generation to generation (hereditary cancer). About 5-10% of cancers are caused by inherited genetic mutations.

Many familial cancer syndromes are caused by inherited mutations in tumor suppressor genes. These are genes that normally keep cells in check by slowing down division (to make new cells), repairing DNA damage, or telling cells to die at the right time.

Family cancer syndrome

According to American Cancer Society, in a family there can be many people with cancer. Some signs suggest that it is more likely that cancers in a family are caused by an inherited gene mutation, such as:

Cancer that occurs at a younger age than usual (such as colon cancer in a 20-year-old).

– More than one type of cancer in a person (like a woman with both breast and ovarian cancer).

Cancer occurs in two organs (such as both eyes, both kidneys, or both breasts).

Having more than one younger cancer in a sibling (such as sarcoma in both a brother and a sister).

Cancer that occurs in a sex that is usually not affected (such as breast cancer in men).

– Cancer occurs in many generations (such as in grandfathers, fathers and sons).

Having multiple family members with cancer can cause anxiety in family members. Image: Freepik

Having two relatives with cancer is of concern if they are on the same side of the family. For example, if both relatives are mother’s brothers than if one is father’s brother and the other is mother’s brother.

The type of cancer is also important. More relatives with the same cancer are more concerning than several different types of cancer. However, in some familial cancer syndromes, several types of cancer seem to go together. For example, breast and ovarian cancers often run in families with hereditary breast and ovarian cancer (HBOC) syndromes. Colon cancer and endometrial cancer tend to go together in Lynch syndrome.

Many cases of the same rare cancer are more worrisome than cases of common cancers. For some rare cancers, the risk of familial cancer syndrome is relatively high with even one case.

The age of the patient when diagnosed with cancer is also important. For example, colon cancer is rare in people under 30. Having a close relative under the age of 30 with colon cancer can be a sign of an inherited cancer syndrome.

Certain types of benign (non-cancerous) tumors are also sometimes part of familial cancer syndromes. For example, people with multiple endocrine neoplasia type two have an increased risk of certain types of thyroid cancer. They can also develop benign tumors of the parathyroid glands and produce tumors of the adrenal medulla (pheochromocytomas), which are usually benign.

Multiple relatives with the same type of cancer may be associated with a risk factor such as smoking. For example, lung cancer is often caused by smoking. Therefore, some cases of lung cancer in a family of heavy smokers are more likely to be caused by smoking than by genetics.

Some cases of familial cancer syndrome

There are many familial cancer syndromes such as breast cancer, ovarian cancer, Lynch syndrome, Li-Fraumeni syndrome. Here are some examples.

Hereditary breast and ovarian cancer syndrome

In some families, many women develop breast and/or ovarian cancer. Often these cancers are found in younger-than-normal women, who may have more than one cancer (such as breast cancer in both breasts or both breast cancer and ovarian cancer). This is called hereditary ovarian and breast cancer (HBOC). Usually, HBOC is caused by an inherited mutation in the BRCA1 or BRCA2 gene.

Lynch syndrome

Lynch is hThe most common genetic syndrome that increases the risk of colon cancer, is also known as hereditary nonpolyposis colorectal cancer (HNPCC). People with this syndrome have an increased risk of colorectal cancer. Most of these cancers develop before they are 50 years old.

Lynch syndrome also leads to an increased risk of endometrial, ovarian, stomach, small intestine, pancreatic, kidney, brain, ureter, and bile duct cancers. Possible causes are mutations in mismatch repair (MMR) genes including MLH1, MSH2, MSH6, PMS1 and PMS2.

Li-Fraumeni . syndrome

Li-Fraumeni is a rare genetic syndrome that can lead to the development of several cancers, including sarcomas (such as osteosarcoma and soft tissue sarcoma), leukemia, and brain (central nervous system) cancers. ), adrenocortical cancer and breast cancer. These diseases often develop in relatively young people. People with Li-Fraumeni can also develop more than one cancer in their lifetime, often caused by an inherited mutation in the TP53 tumor suppressor gene.

Because genetic mutations affect all cells of the body, they can be found by genetic testing through blood or saliva samples. However, genetic testing may not be helpful for everyone. You can seek appropriate advice from a genetics specialist.

Kim Uyen
(According to American Cancer Society)

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