Is cancer contagious? Scientists get the answer after injecting cancer cells into healthy people

Today, many studies have confirmed that cancer can be inherited. The American Cancer Society believes that about 5 to 10% of cancer cases are related to inherited genetic errors . But did you know that cancer is contagious?

In the "American Journal of Organ Transplantation", a case was reported: a 53-year-old female organ donor died of a stroke. After a series of examinations, he was eligible for donation and finally donated kidneys, lungs, livers and hearts. .

And patients who received transplants developed cancer in the later stages :

A patient who received lung transplantation was found to have lung cancer 16 months after transplantation and had already metastasized, and died of cancer 1 year later;

Two women who had left kidneys and livers transplanted were also diagnosed with cancer and eventually died of cancer;

Another man who received a right kidney transplant was found to have metastatic breast cancer cells. Due to timely treatment, he saved his life and is currently waiting for another kidney transplant.

Although this is an extreme case, it still makes people curious, is cancer really contagious? In fact, as early as the mid-twentieth century, some scientists injected cancer cells into the human body and got the answer.

1. What happens when cancer cells are injected into a healthy human body?

To understand how cancer spreads, American medical scientist Chester Southam conducted human experiments.

In the beginning, afraid of taking risks and responsibilities, he selected more than a dozen patients with cancer and injected them with cancer cells "Hella cells", and finally found that only one died due to cancer cells.

Since it could not prove that injecting cancer cells will cause cancer, he turned his attention to American prisoners. He recruited a total of 20 healthy adult male volunteers from the prison, indicating that this is a cancer trial.

After obtaining consent, he injected the volunteers with HeLa cancer cells several times within a few months, and finally found that all the prisoners rely on their own immune systems to defeat the foreign cancer cells , and each injection reduces the swelling. less time.

It can be seen that human cancer cells are not directly infected. After injecting cancer cells into the body, they are generally recognized and eliminated by the immune system in the body soon .

However, it should be emphasized that in some specific cases, cancer still has conditions for transmission. For example, if a woman has cancer during pregnancy, the cancer cells may be transmitted from the mother to the fetus; or in organ transplantation, such as the donated organ contains cancer cells, It can also lead to the spread of cancer.

Therefore, in the face of the spread of cancer, we still have to be vigilant and take precautions.

2. Cancer is not contagious, but carcinogens are contagious

For cancer, what we really need to worry about is that some carcinogens are contagious. According to the "2018 Global Cancer Statistics", there were 18.1 million new cases worldwide in 2018, of which 2.2 million were caused by infectious pathogens, accounting for the total number of cases. Nearly 13%, especially the following three carcinogenic factors are the most common.

1. Helicobacter pylori (Hp)

Very high incidence in China, mainly through oral-oral (saliva or oral secretions), fecal-oral transmission, is one of the main causes of gastric cancer, has been classified as a first-class carcinogen.

Helicobacter pylori is highly contagious, so it is necessary to strengthen prevention, and usually put more effort into the "mouth". For example, it is best to use public chopsticks for meals, or to adopt a divided meal system; family members try to avoid sharing vegetables with each other; Be sure to remember to wash your hands; utensils are regularly sanitized, etc.

2. Hepatitis B virus (HBV)

China is a big country with liver cancer, and 85% to 90% of liver cancers are related to hepatitis B. The hepatitis B virus can be transmitted through mother-to-child, blood and sexual contact.

So if you want to prevent HBV infection, you can start from these aspects:

• Get the hepatitis B vaccine in advance;
• Develop good hygiene habits and do not share personal items such as toothbrushes, razors, etc.;
• If female hepatitis B patients have fertility requirements, they need to consult a professional doctor for formal blocking to prevent the virus from being transmitted to the fetus or newborn.

3. Human papillomavirus (HPV)

HPV is mainly sexually transmitted and may cause cervical cancer, vaginal cancer, vulvar cancer, anal cancer and other cancers, among which cervical cancer is the most common.

To prevent HPV infection, the most direct and effective way is to get HPV vaccine . Avoid multiple sexual partners at the same time, use condoms as much as possible during sex; strengthen physical exercise and improve immunity.

It can be seen from the above that cancers in certain parts may indeed be transmitted from person to person, and the closer the relationship is, the easier it is to be recruited, so we must pay attention to prevention.

3. 5% of cancers are inherited, how can the remaining 95% be prevented?

A study published by Canadian researchers in the medical journal "Metabolites" pointed out that although cancer is a genetic disease, heredity is only one of the causes. We also need to consider factors such as environment and metabolism .

• These 4 types of cancer have high genetic risk

Breast cancer : Breast cancer is very likely to be hereditary, especially among immediate family members. For example, if a mother develops breast cancer, her daughter is 2-3 times more likely to develop breast cancer than the average person . It is recommended that those with family history do a good job of "breast self-examination" and professional screening work, including B-ultrasound, mammography, etc.

Gastric cancer : There is an obvious family aggregation phenomenon in gastric cancer. For example, if more than two parents and grandparents in the family have (diffuse) gastric cancer , and the age of onset is less than 50 years old, it is necessary to be highly alert to hereditary gastric cancer. It is recommended to perform gastroscopy on a regular basis so that abnormalities can be detected in time; in the event of abdominal pain, abdominal distension and other discomfort, seek medical treatment in time.

Liver cancer : The incidence of liver cancer also has an obvious tendency to cluster in families. Because HBV virus can be transmitted vertically, people with family history are recommended to have a comprehensive liver examination every 1 year, such as complete liver function tests, B-ultrasound, etc.

Bowel cancer : hereditary rate is 20%-30% , so if there is a family history, regular colonoscopy screening should also be carried out. If there is any abnormality such as mucus stool, blood in the stool, frequent stools, etc., seek medical attention in time.

• Away from carcinogenic environment

Minimize or avoid exposure to occupational carcinogenic environments, such as ionizing radiation, UV exposure to vinyl chloride, radon, etc. It is recommended that those engaged in occupations such as asbestos workers, miners, painters, leather workers, etc., pay attention to taking necessary occupational exposure protection .

• stick to a healthy lifestyle

A study published in "Nature-Metabolism" shows that a variety of epidemiological data have confirmed that an unhealthy lifestyle is one of the main factors leading to a high incidence of cancer .

Among them, we must be highly vigilant about the risk factor of obesity, which can lead to abnormal metabolism and immune function, which can disrupt body homeostasis and accelerate the occurrence of cancer. Therefore, usually pay attention to diet control, active exercise, help maintain and restore the balance of the body, thereby preventing cancer.

Summary: There is a high incidence of cancer, especially some cancers may be "infectious", so everyone should be vigilant, especially those with a family history of cancer, to strengthen prevention, and don't be fooled by cancer " target ".

References:

[1] Is Cancer Contagious? American medical scientists have injected cancer cells into healthy people". Penguin Science. 2018-12-20

[2] Is cancer hereditary? Oncologist: Absolutely! These 5 types of cancer are most likely to be inherited! ". Health Times. 2020-07-11

[3] How did cancer come about? How to prevent it? This article is all clear...". Popular Science China. 2022-03-06

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