Genotoxicity biomarkers in occupational exposure to formaldehyde: the case of histopathology laboratories

Formaldehyde, classified by the IARC as carcinogenic in humans and experimental animals, is a chemical agent that is widely used in histopathology laboratories. The exposure to this substance is epidemiologically linked to cancer and to nuclear changes detected by the cytokinesis-block micronucleus test (CBMN). This method is extensively used in molecular epidemiology, since it provides information on several biomarkers of genotoxicity, such as micronuclei (MN), which are biomarkers of chromosomes breakage or loss, nucleoplasmic bridges (NPB), common biomarkers of chromosome rearrangement, poor repair and/or telomere fusion, and nuclear buds (NBUD), biomarkers of elimination of amplified DNA. The aim of this study is to compare the frequency of genotoxicity biomarkers, provided by the CBMN assay in peripheral lymphocytes and the MN test in buccal cells, between individuals occupationally exposed and non-exposed to formaldehyde and other environmental factors, namely tobacco and alcohol consumption. The sample comprised two groups: 56 individuals occupationally exposed to formaldehyde (cases) and 85 unexposed individuals (controls), from whom both peripheral blood and exfoliated epithelial cells of the oral mucosa were collected in order to measure the genetic endpoints proposed in this study. The mean level of TWA8h was 0.16±0.11ppm (

Genotoxicity biomarkers in occupational to formaldehyde in pathology anatomy laboratories

Formaldehyde (FA) the most simple and reactive of all aldehydes, is a colorless, reactive and readily polymerizing gas at normal temperature. It has a pungent, suffocating odour that is recognized by most human subjects at concentrations below 1ppm. According to the Report on Carcinogens, FA ranks 25th in the overall U.S. chemical production with more than 11 billion pounds (5 million tons) produced each year. Is an important industrial compound that is used in the manufacture of synthetic resins and chemical compounds such as lubricants and adhesives. It has also applications as a disinfectant, preservative and is used in cosmetics. Estimates of the number of persons who are occupationally exposed to FA indicate that, at least at low levels, may occur in a wide variety of industries. The occupational settings with most extensive use of formaldehyde is in the production of resins and in anatomy and pathology laboratories. Several studies reported a carcinogenic effect in humans after inhalation of FA, in particular an increased risk for nasopharyngeal cancer. Nowadays, the International Agency for Research on Cancer (IARC) classifies FA as carcinogenic to humans (group 1), on the basis of sufficient evidence in humans and sufficient evidence in experimental animals. Manifold in vitro studies clearly indicated that FA is genotoxic. FA induced various genotoxic effects in proliferatin cultured mammalian cells. A variety of evidence suggests that the primary DNA alterations after FA exposure are DNA-protein crosslinks. Incomplete repair of DPX can lead to the formation of mutations.

Risk assessment in occupational exposure to formaldehyde: differences between anatomy and pathology laboratories and formaldehyde-resins production

Formaldehyde (CH2O), the most simple and reactive of all aldehydes, is colorless, and readily polymerizing gas at normal temperature. The most extensive use is in production of resins and has an important application as a disinfectant and preservative, reason why relevant workplace exposure may also occur in pathology and anatomy laboratories and in mortuaries. A study was carried out in Portugal, in a formaldehyde production resins factory and in 10 pathology and anatomy laboratories. It was applied a risk assessment methodology based on Queensland University proposal that permitted to perform risk assessment for each activity developed in a work station. This methodology was applied in 83 different activities developed in the laboratories and in 18 activities of the factory. Also, Micronucleus Test was performed in lymphocytes from 30 factory workers and 50 laboratories workers.

Occupational exposure to formaldehyde in anatomy and pathology laboratories: differences between exposure groups?

Formaldehyde, also known as formalin, formal and methyl aldehydes, is a colorless, flammable, strong-smelling gas. It has an important application in embalming tissues and that result in exposures for workers in the pathology anatomy laboratories and mortuaries. To perform exposure assessment is necessary define exposure groups and in this occupational setting the technicians and pathologists are the most important groups. In the case of formaldehyde, it seems that health effects are more related with peak exposures than with exposure duration.

Genotoxicity biomarkers: application in histopathology laboratories

Most cancers results from man-made and natural environmental exposures (such as tobacco smoke; chemical pollutants in air, water, food, drugs; radon; and infectious agents) acting in concert with both genetic and acquired characteristics. It has been estimated that without these environmental factors, cancer incidence would be dramatically reduced, by as much as 80%-90%. The modulation of environmental factors by host susceptibility was rarely evaluated. However, within the past few years, the interaction between environmental factors and host susceptibility factors has become a very active area of research. Molecular biology as a tool for use in epidemiological studies has significant potential in strengthening the identification of cancers associated with environmental exposures related to lifestyle, occupation, or ambient pollution. In molecular epidemiology, laboratory methods are employed to document the molecular basis and preclinical effects of environmental carcinogenesis. Molecular epidemiology has become a major field of research and considerable progress has been made in validation and application of biomarkers and its greatest contribution has been the insights provided into interindividual variation in human cancer risk and the complex interactions between environmental factors and host susceptibility factors, both inherited and acquired, in the multistage process of carcinogenesis.

Genotoxic effects in occupational exposure to formaldehyde: A study in anatomy and pathology laboratories and formaldehyde-resins production

Background - According to the Report on Carcinogens, formaldehyde ranks 25th in the overall U.S. chemical production, with more than 5 million tons produced each year. Given its economic importance and widespread use, many people are exposed to formaldehyde environmentally and/or occupationally. Presently, the International Agency for Research on Cancer classifies formaldehyde as carcinogenic to humans (Group 1), based on sufficient evidence in humans and in experimental animals. Manyfold in vitro studies clearly indicated that formaldehyde can induce genotoxic effects in proliferating cultured mammalian cells. Furthermore, some in vivo studies have found changes in epithelial cells and in peripheral blood lymphocytes related to formaldehyde exposure. Methods - A study was carried out in Portugal, using 80 workers occupationally exposed to formaldehyde vapours: 30 workers from formaldehyde and formaldehyde-based resins production factory and 50 from 10 pathology and anatomy laboratories. A control group of 85 non-exposed subjects was considered. Exposure assessment was performed by applying simultaneously two techniques of air monitoring: NIOSH Method 2541 and Photo Ionization Detection equipment with simultaneously video recording. Evaluation of genotoxic effects was performed by application of micronucleus test in exfoliated epithelial cells from buccal mucosa and peripheral blood lymphocytes. Results - Time-weighted average concentrations not exceeded the reference value (0.75 ppm) in the two occupational settings studied. Ceiling concentrations, on the other hand, were higher than reference value (0.3 ppm) in both. The frequency of micronucleus in peripheral blood lymphocytes and in epithelial cells was significantly higher in both exposed groups than in the control group (p < 0.001). Moreover, the frequency of micronucleus in peripheral blood lymphocytes was significantly higher in the laboratories group than in the factory workers (p < 0.05). A moderate positive correlation was found between duration of occupational exposure to formaldehyde (years of exposure) and micronucleus frequency in peripheral blood lymphocytes (r = 0.401; p < 0.001) and in epithelial cells (r = 0.209; p < 0.01). Conclusions - The population studied is exposed to high peak concentrations of formaldehyde with a long-term exposure. These two aspects, cumulatively, can be the cause of the observed genotoxic endpoint effects. The association of these cytogenetic effects with formaldehyde exposure gives important information to risk assessment process and may also be used to assess health risks for exposed workers.