Why does formaldehyde cause leukemia?

Introduction: Mouse experiments show that formaldehyde may affect the expression of some cancer-related genes after entering the body; Epidemiological studies show that when people are exposed to formaldehyde, the risk of leukemia may increase. However, the occurrence of leukemia is the result of many factors, and formaldehyde may be only one of the incentives. Formaldehyde is a colorless and irritating chemical at room temperature. Indoor, its main source is decoration materials. In addition to plywood and artificial ceilings commonly used in interior decoration, even wallpaper and carpets contain formaldehyde gas. Formaldehyde has certain influence on human health. Toxicological studies show that when inhaled formaldehyde concentration is greater than 0.24ppm, people will become irritable and aggressive, while when inhaled formaldehyde concentration is greater than 13.8ppm, it will lead to respiratory discomfort such as tears and cough. Can formaldehyde cause cancer? The International Agency for Research on Cancer (IARC) of the World Health Organization lists formaldehyde as the first carcinogen. In 1980s, laboratory studies showed that exposure to formaldehyde may lead to nasal cancer in rats. This discovery raises the question of whether formaldehyde exposure will lead to human cancer. Since then, the National Cancer Institute has initiated a series of studies to find the relationship between formaldehyde exposure and cancer risk. They surveyed professionals exposed to formaldehyde at work, such as anatomists, and found that these people had an increased risk of leukemia and brain cancer compared with the general population. In the study of funeral workers, the researchers studied the funeral workers who died during 1960-1986. They compared people who died of leukemia, lymphoma and brain tumor with those who died of other causes. The results show that people who have more exposure to preservatives, that is, people who have more exposure to formaldehyde, have the highest risk of bone marrow leukemia. However, with the current research evidence, it can not be completely proved that excessive indoor formaldehyde will definitely lead to adult leukemia, because the pathogenic factors are often diverse and complicated. Because cancer is the result of many factors, not only external factors such as formaldehyde, but also internal factors such as oncogenes. So the most accurate statement should be that excessive exposure to formaldehyde will increase the risk of leukemia. Zhang Qunling, Department of Hematology, Shanghai Cancer Hospital affiliated to Fudan University, said that in terms of decoration materials, there are also many organic solvents and chemical components, not just formaldehyde. Like pathologists who are often exposed to formalin (formaldehyde solution), the incidence of leukemia has not increased. What is the relationship between formaldehyde and leukemia? At present, some studies have shown that in vitro experiments, after formaldehyde binds to DNA molecules, DNA chains that were originally arranged in a double helix structure can be broken and cross-adhered. Some researchers have suggested that there may be three mechanisms of formaldehyde-induced leukemia. First, like other causes of leukemia, it can directly destroy stem cells in bone marrow; The second is to destroy peripheral blood hematopoietic stem cells, which may lead to leukemia after entering bone marrow; The third is to destroy multifunctional stem cells in tissues such as nasal mucosa, which can enter bone marrow through blood and lead to leukemia. In addition, in mouse experiments, the researchers found that the expression of several genes was also affected by formaldehyde. With the increase of formaldehyde concentration, the expressions of c-myc gene (a gene promoting cell division), MDM2 gene (an oncogene related to tumor metastasis) and p53 gene (a tumor suppressor gene) in mouse bone marrow tissue will all change. The former two genes will become more active, while the latter one will be inhibited to some extent. Overexpression of the first two genes may destroy the anticancer function of p53 through some mechanisms. This may also be a mechanism of leukemia caused by formaldehyde. However, the above possible mechanisms are all found in mouse experiments, and only at the level of gene expression. At present, there is no clear conclusion about what kind of physiological and biochemical reaction formaldehyde will cause in human body. How to discharge indoor formaldehyde? Since we know that long-term excessive exposure to formaldehyde may bring health risks such as leukemia, we need to be vigilant and take precautions in our daily life. First of all, we should understand that the release of formaldehyde is a long-term process, which is related to indoor temperature, relative humidity, indoor air exchange times and indoor building materials. In the family environment, reasonable control room environment is an effective way to reduce formaldehyde concentration. Indoor ventilation is an effective method to remove formaldehyde. Ventilation device or natural ventilation is beneficial to the emission and discharge of formaldehyde in indoor materials. We can determine the ventilation frequency according to different seasons, weather and the number of people in the room. For example, ventilation openings can be properly left in spring, summer and autumn, and windows should be opened for ventilation for at least 30 minutes every day in cold winter. In addition, it was found that the release of formaldehyde increased with the increase of humidity and temperature. When the temperature drops from 30℃ to 25℃, the formaldehyde emission can be reduced by 50%, the relative humidity from 70% to 30%, and the formaldehyde emission can be reduced by 40%. If formaldehyde in indoor materials is to be released as soon as possible, the temperature and humidity can be increased. Therefore, the newly renovated houses are generally baked or fresh water is placed indoors, which can speed up the emission of formaldehyde in indoor materials and then discharge formaldehyde through ventilation. From the source, choosing products that meet environmental protection standards when decorating and buying furniture at home can greatly reduce the formaldehyde content at home. Self-test formaldehyde, is it reliable? In order to know whether the formaldehyde content in their home exceeds the standard, many people will test it. Some people buy some portable instruments online and do it themselves, while others find professional companies to do it. What is the accuracy of the test data? Someone once bought a portable formaldehyde detector online, but finally found that the value measured by the detector has a great relationship with air flow. The values detected by the same air sample in the static container and the shaking container are completely different. Some researchers say that portable detectors can be roughly divided into two types, one is semiconductor detector and the other is electrochemical detector. Either way, it will be affected by the air velocity. Such a detector does not conform to the national standard detection method, and when compared with the national standard detection method, it will find that the numerical deviation is large. If formaldehyde is detected according to strict national standards, there are clear requirements for indoor temperature and sealing time. According to the indoor air quality standards formulated by the Ministry of Health, doors and windows need to be closed 12 hours before formaldehyde detection, and doors and windows need to be closed during detection, so as to be as close as possible to the daily living conditions, so as to measure whether the house meets the sanitary requirements of the living environment. The relevant standards also have strict regulations on the extraction and detection of indoor air samples. For example, when sampling, in principle, rooms below 50 square meters should provide 1~3 points; There are 3 to 5 points in 50- 100 square meter, and at least 5 points above 100 square meter. These sampling points need to be evenly distributed on the diagonal or quincunx. In addition, the height of the sampling point should be consistent with the height of the human breathing zone. After sampling, it is necessary not only to send the sample back to the laboratory, but also to record the pressure, temperature, relative humidity and wind speed at that time in detail, so as to conduct a comprehensive inspection during the final inspection. According to these standards, the formaldehyde concentration is relatively accurate. Author | Li Xiaohui Author Reviewer | Zhang Qunling, Deputy Chief Physician of Oncology Department of Fudan University Cancer Hospital, published by Tencent Popular Science "Popular Science China Headline Creation Promotion Project". Please indicate some facts about formaldehyde quoted from Popular Science China: 1 ki.net/KCMS/detail/detail.aspx?. . db code = CJFQ & amp； dbname = cjfd 20 13 & amp； filename = zghj 20 130803 1 & amp； V = mjc5mjledfom3 fucldnmuzyq1vstedmyncuz5amdvnnznjuhlyrfpmrzri 3 Toxic effect of formaldehyde on bone marrow tissue in mice ki.net/KCMS/detail/detail.aspx? db code = CJFQ & amp； dbname = cjfd 20 12 & amp； File name = zghj201206035 &; V = mjkxndzlzmj1wnfgewpovnj6tvb5ckratec0sdlqtxfoudzwi4zvgxthv4wm3 Discussion on detection methods and control strategies of formaldehyde in indoor air/upload file/file/GB18883.pdf 6 Summary of rapid detection methods of formaldehyde and TVOC in indoor main pollutants/5/20/kloc-0.