Formalin Induced Micronucleus Formation in the Buccal Mucosa of Pathology Laboratory Workers

Background Objective: Formaldehyde is an irritating substance that is categorized as a definite carcinogen (Group A1), according to the International Agency for Research on Cancer (IARC). This study was conducted to determine the role of this substance in the frequency of micronuclei (MN) in the buccal mucosal cells due to long-term exposure of the pathology staff to formaldehyde.Methods: In this case-control study, 32 pathology laboratory staff members were assigned to the case group, and 32 staff members who were not exposed to formaldehyde were assigned to the control group. Buccal mucosa cells were collected with a wet spatula and stained with Papanicolaou stain. In each sample, 500 cells were counted; then, the frequency of MN and the average number of MN in the micronucleated cells were assessed and compared between the 2 groups using the independent t test. Furthermore, the relationship between gender and MN was evaluated using the independent t test. The relationship between years of exposure and time of exposure during the day (in hours) for the case group, as well as the relationship between age and frequency of MN was analyzed using the Pearson correlation coefficient.Results: The mean frequency of MN in exfoliated buccal cells was 18.33±12.36 in the case group, which was significantly higher than the control group (10.55±6.22; P=0.003). The difference in the mean number of total MN in the micronucleated cells was not significant between the case and control groups (P=0.11). The relationship between sex, age, and years of exposure with the mean frequency of MN and the total number of MN in the micronucleated cells was not significant. The relationship between exposure time during the day and both the mean frequency of MN and the total number of MN in the micronucleated cells was significant (P=0.03).  Conclusion: Formaldehyde exposure and extended time of exposure during the day can increase the frequency of MN, which can prognosticate the incidence of precancerous and cancerous lesions. Therefore, continuous exposure to formaldehyde can be considered an occupational health hazard, though further studies are needed to confirm this result.