Is cancer hereditary?

Recently, after giving birth to her second child, 36-year-old Ms. Luo accidentally discovered that her "thyroid nodules" had suddenly grown larger. She immediately went to the hospital for a check-up and was finally diagnosed with anaplastic thyroid cancer, a type of thyroid cancer with a very high risk and poor prognosis. During the treatment, she thought about one thing: her grandmother died early due to cancer, her father had four types of cancer, her brother had lymphoma, her two aunts had breast cancer, her uncle had a history of liver cancer, her cousin was a lung cancer patient, and her cousin died of lung cancer...

"Eight people in a family have cancer, and they were all young when they were diagnosed." Seeing a family with cancer, many people probably think of heredity first. So is cancer hereditary? This kind of question is sometimes like a definition problem. Today, let's talk about whether cancer is hereditary!

01. Cancer is not hereditary, but there is a hereditary tendency

If you understand heredity as the traditional "like dragons give birth to dragons, like phoenixes give birth to phoenixes", then cancer is not hereditary. A child born to a cancer patient will not be born with cancer. However, this does not mean that the disease will not be inherited, but that a tendency will be inherited.

Let us think about the pathogenesis of cancer. According to current views, the theory of cancer can be roughly understood as: mutation - carcinogenesis - breakthrough of immunity - cancer.

When our body's DNA mutates due to various factors, such as physical ultraviolet or X-ray irradiation, chemical carcinogens, biological viruses, self-replication errors, etc., most of them will be repaired or cleared, but some will become cancerous. In other words, it should be made clear here: mutation and cancer are not the same.

Even if it turns into cancer, the human body still has the immune system to eliminate it. Only when the immune system is broken through and it begins to proliferate and form cancerous tissue, then we call it cancer.

It can be seen that basically, mutation is the basis. Since mutation is basically uncontrollable, the human body has a quality control system - which can be understood as a quality inspection system . If this quality inspection mechanism also mutates, such as the repair efficiency decreases, then these mutations may begin to grow and develop.

Therefore, many of the cancer genes we observe are genes responsible for quality inspection.

For example, the picture above shows the 10 genes that Nature summarized that humans are most concerned about, most of which are cancer-related genes.

For example, TP53, the first on the hot list, is a standard quality control gene that checks and corrects errors during cell division and proliferation. If it mutates, fails to detect mutations in the human body, or its efficiency decreases, then the possibility of cancer development is high.

Because of this, when we talk about the hereditary nature of cancer, we are mainly referring to this type of inheritance.

That is, if a family has more mutations in TP53, which is heritable, then their probability of developing cancer will increase.

02. Not just cancer

In fact, many diseases have a tendency to be inherited, or it can be said to be an inheritance of risk factors. This is what we found when processing various data. Many diseases, especially chronic diseases such as cancer, cardiovascular disease, diabetes, etc., have very significant family clustering problems. The performance is that in a family, almost all direct descendants have a higher probability of suffering from the disease than the normal incidence rate.

In general, these diseases include, but are not limited to, the following:

Chronic diseases: cancer, coronary heart disease, diabetes, osteoporosis

Physical signs: blood pressure, cholesterol

The reasons here are complex and include both external and genetic factors:

External causes mainly include living habits and living environment. For example, if a family likes to eat salty food, then the proportion of hypertension in this family will definitely be high.

The internal cause is genetic factors, that is, gene problems. Many diseases are complex diseases, determined by multiple genes, and each gene is very large (basically a small one has a few thousand bases, and a large one has hundreds of thousands of bases). Many families will have some mutations, and this mutation may not directly cause the disease, but it will increase the risk, or susceptibility.

Therefore, in the hospital, responsible doctors will definitely ask about your family medical history. At the same time, please pay attention to your own family to see if there are similar phenomena. If so, then you must pay more attention. Regular physical examinations, focus on observing certain items (for example, families with high blood pressure must pay attention to blood pressure values)

In addition, you should pay attention to certain symptoms. Most indicators are statistical data, such as the normal range of high blood pressure is 90-140. This range is very large, and you cannot think that 90 before and 139 now are both normal. In fact, for you, this is already very abnormal because your blood pressure has increased by 55%. Therefore, you must read the physical examination form carefully and compare it with the data of previous years.

Many cancer patients have mutations such as TP53, or mutations like BRCA1 for breast cancer. This mutation is hereditary, which means that the probability of cancer in offspring will increase significantly.