Leukemia is a class of malignant hematologic tumors that originate from hematopoietic stem cells. It is currently ranked as the sixth most prevalent tumor in China, with limited clinical treatment, high recurrence and mortality rates, and prevention is the key.
Leukemia occurs as a chronic cumulative process of atypical proliferation of hematopoietic stem cells caused by the susceptibility of the body, continuous exposure to carcinogenic substances and weakening of the body’s immune surveillance system, which gradually turns into malignant clonal proliferation until the number reaches the threshold of tumorigenesis. Therefore, prevention of leukemia should start from the following aspects:
First, be eugenic.
Many children with genetic disorders and congenital chromosomal aberrations are highly susceptible to leukemia. For example, Fanconi anemia, Down syndrome caused by trisomy 21, congenital immunodeficiency disorders, etc. Strict prenatal screening is essential.
It is also critical to avoid the effects of viruses (HIV, syphilis, human leukemia herpes virus, etc.), chemicals, and other factors on the fertilized egg and fetus during pregnancy.
Second, try to avoid disease-causing factors.
It is also critical for individuals to try to avoid ongoing exposure to currently known causative factors of leukemia. There are several broad categories of currently recognized etiologic factors:
Biological factors: including viruses, parasites, etc.
- Viral factors: The primary genetic material of viruses is RNA, and integration into other organisms alters the cytogenetic information of the latter. The role of HIV and EBV, among others, in triggering leukemia in animals such as mice, cats, chickens, and cattle has been experimentally confirmed.
- Parasites: Other parasites such as Toxoplasma gondii, which is found in pets such as dogs and cats, and some other parasites that are more invasive, can also have adverse effects on the body. Therefore, it is important to pay attention to protection in infected areas and reduce the stay, and to provide regular vaccination for pets, etc.
Chemical factors: There are three categories of direct carcinogens, indirect carcinogens, and carcinogenic agents according to their mode of action.
- Direct carcinogens: These are chemical carcinogens that enter the body and interact directly with cells in the body to induce cancer in normal cells without metabolism. These chemical carcinogens have strong carcinogenic power and rapid carcinogenic effects, and are often used in studies of malignant transformation of cells in vitro. For example, various carcinogenic alkylating agents (such as hair dyes, and a major class of chemotherapeutic agents for the treatment of many tumors, including cyclophosphamide, bendamustine, etc., so they can cause leukemia in patients 2 to 5 years after treatment of the primary tumor, called a second tumor), nitrosamines (overnight food, etc.) carcinogens, etc.
- Indirect carcinogens: These are chemical carcinogens that require activation by microsomal mixed function oxidases in the body to become chemically active before they can have a carcinogenic effect. The most common are polycyclic aromatic hydrocarbons, aromatic amines, nitrosamines and aflatoxins (found in paints, industrial glues, moldy foods, etc.).
- Carcinogens: Also known as tumor promoters, they have no carcinogenic effect in the body alone, but can promote other carcinogens to induce tumor formation. Common carcinogens include croton oil, saccharin, and phenobarbital (seen in food additives, etc.). Care needs to be taken to reduce exposure and continued use.
Radiological factors: Various long-term or high-dose exposures to ionizing radiation have been shown to increase the risk of leukemia, including mainly electromagnetic radiation characterized by short-wave and high frequency, as well as electron, proton, neutron, and alpha particle radiation.
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Ionization causes the body to produce large amounts of free radicals, which are very reactive in nature and can injure biological targets by disrupting normal molecular structures, causing chromosomal aberrations in the body, activating mutations in oncogenes and inactivating oncogenes.
After the atomic bombings in Hiroshima and Nagasaki, Japan, the incidence of leukemia was 17 to 30 times higher in the heavily irradiated areas than in the unirradiated areas. The incidence of leukemia increased each year for 3 years after the bombing, peaking at 5-7 years. It took 21 years for its incidence to return to levels close to those seen throughout Japan.
The incidence of leukemia was significantly increased in radiation workers, those with frequent exposure to radioactive materials (e.g., cobalt-60).
There is still insufficient evidence that small doses of radiation can cause leukemia.
A final point to emphasize is the maintenance of the body’s immunity. A normal lymphatic system, especially its NK and T cells, has a clearing effect on abnormally proliferating cells. A good lifestyle and environment, moderate physical activity, and regular medical checkups protect and monitor the body’s immunity. Once symptoms such as bleeding, infection, anemia, and abnormal blood tests that progress faster in a short period of time, timely consultation with the hematology department for early identification and diagnosis is also a positive means to actively prevent and treat the adverse consequences of leukemia.