Copyright © 2016 Basem Hassan Elesawy et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. International Journal of Basic and Applied Sciences, 5 (3) (2016) 172-176 International Journal of Basic and Applied Sciences Website: www.sciencepubco.com/index.php/IJBAS doi: 10.14419/ijbas.v5i3.6379 Research paper Application of Bethesda terminology to categorize buccal epithelial smears among petroleum station workers in Taif city, KSA Basem Hassan Elesawy 1, 2 , Amal Abd El-hafez 1, 3 *, Abdelaty Shawky Mohamed 1, 4 , Magdi Mansour A. Salih 5 1 Pathology Department, Faculty of Medicine, Mansoura University, Egypt 2 Medical Laboratory Department, Faculty of Applied Medical Sciences, Taif University, KSA 3 Basic Medical Sciences Department, College of Medicine, Al-farabi Colleges, Riyadh, KSA 4 Al Maarefa College for Science and Technology, Riyadh, KSA 5 Department of Histopathology and Cytology, Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan *Corresponding author E-mail: amalabdelhafez@gmail.com Abstract Background and Objectives: Exposure to Petroleum products has a well-established mutagenicity and carcinogenicity of some compo- nents such as benzene. Buccal mucosal cells are capable of metabolizing the carcinogenic compounds to reactive chemicals. We investi- gated the buccal epithelial cell cytological changes resulting from the occupational exposure to Petroleum derivatives such as benzene. Methods: Samples were obtained from 70 Petrol station workers in Taif city-KSA, examined using the Papanicolaou stained smears and categorized based on Bethesda Terminology System. Statistical analysis was carried out with the SPSS. Results: About 38.6% of petrol station workers exhibited buccal cytological changes ranging from atypical squamous cells of undeter- mined significance (ASC-US) to high-grade squamous intraepithelial lesions (HSIL). Atypical squamous cells, cannot exclude high- grade squamous intraepithelial lesion (ASC-H) was the most frequent cytological abnormality. Buccal smears with abnormal cytological findings dominated among smokers in contrast to non-smokers with a statistically significant difference (P = 0.026). No significant asso- ciations were detected between the category of buccal cytological changes and the duration of work or the participant's age. Conclusion: Bethesda Terminology System can be efficiently applied to buccal smears. Petrol products induce precancerous epithelial changes in buccal epithelial cells indicating a potential health risk for Petrol station workers, thus annual checkup for those workers should be set as primary prevention of occupational-related cancer. Cigarette smoke is a co-factor that exacerbates the effects of Petrol derivatives. Keywords: Benzene; Bethesda System Terminology; Buccal Mucosa; Carcinogenic; Smear. 1. Introduction Petroleum products are a complex mixture of aliphatic and aro- matic hydrocarbons with high volatility. Such types of hydrocar- bons exhibit co-mutagenic and co-carcinogenic properties [1]. Exposure to Petroleum (gasoline) vapors is classified by the Inter- national Agency for Research on Cancer (IARC) as possibly car- cinogenic to humans, mainly on the basis of the well-established mutagenicity and carcinogenicity of some components such as benzene [2]. Benzene is a widespread environmental chemical with a carcino- genic nature. The current permissible exposure level is 1 part per million (ppm) in air for 8 hours [3]. The association between ex- posure to benzene or benzene-containing mixtures with acute non- lymphocytic (myeloid) leukemia, hemato-toxicity and other bone marrow disorders has been shown in epidemiological studies in different countries [4], [5]. The carcinogenic mechanisms of ben- zene have been demonstrated through in vitro models. Some of the reactive metabolites of benzene, such as phenol, catechol, and hydroquinone, can bind to and damage macromolecules, including DNA [6]. These reactive metabolites may also generate reactive oxygen species (ROS) that can exacerbate the DNA damage [7]. Additionally, alterations in DNA methylation -notably mitochon- drial DNA- have been recently verified to result from low-dose benzene exposure as a direct effect of ROS-induced DNA damage [8]. Exposure to benzene in human populations can occur in various work-related settings in which benzene is used or produced, or from traffic emissions resulting from incomplete combustion of fossil fuel, or from other sources. Work-related exposures to ben- zene occur among Petrochemical laboratory workers and Petrol station workers who pump fuel to vehicles and absorb the products of fuel fumes and the products of combustion [9, 10]. Cigarette smoke is an important source of benzene in indoor air. It repre- sents one of the factors that may influence the rate of benzene exposure-induced cytogenetic damage [10]. Buccal mucosal cells are capable of metabolizing the carcinogenic compounds to reactive chemicals [10]. Additionally, recent studies have demonstrated that petroleum derivatives are able to induce genetic damage and cellular death including micronuclei; binucle- ation and cellular death (pyknosis, karyolysis and karyorrhexis) in buccal mucosal epithelial cells from gas petrol attendants [10], [11]. The Bethesda System Terminology is a system applied for report- ing cervical or vaginal cytological preparations. It was introduced