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.

Micronucleus assay in the exfoliated cells of buccal mucosa of gasoline station workers in Tehran.

Objectives: One of the most critical landmarks of DNA damage is the micronucleus assay. Enumeration of micronuclei contributes to the early diagnosis of precancerous lesions and cancers; however, there are few studies on the frequency of micronucleus in gasoline station workers. To the best of our knowledge, no study has addressed this issue in Iran. The present study aimed to determine the role of working in the gasoline stations of Tehran city on micronucleus frequency in buccal mucosa. Materials and Methods: In this historical cohort study, buccal mucosa samples were collected from 110 individuals working at gasoline stations and 100 unemployed persons using wet tongue depressors. After Papanicolaou staining, the percentage of cells containing micronucleus as well as the mean number of micronucleus in the micronucleated cells was reported. Student's t-test, Mann-Whitney test, and regression analyses were used to specify the effect of other variables on the frequency and mean number of micronucleus per cell. Results: The mean frequency of micronucleus in the case and control group was 29.8 ± 8.2 and 9.3 ± 3.2, respectively, which was statistically significant (P = 0.0001). Furthermore, the mean number of micronucleus in the micronucleated cells of buccal mucosa was significantly higher in individuals who were exposed to gasoline than the control group (P = 0.0001). Conclusion: The results indicated that exposure to gasoline could increase the frequency of micronucleus. It was also revealed that cigarette and hookah smoking and alcohol consumption, together with working in gasoline stations, increase micronucleus abundance, implying the cumulative carcinogenic effect of these factors.

Evaluation of the presence of myofibroblasts and matrix metalloproteinase 1 expression in the stroma of oral verrucous hyperplasia and verrucous carcinoma.

BACKGROUND: Oral verrucous carcinoma is a low-grade subtype of oral squamous cell carcinoma that should be differentiated from oral verrucous hyperplasia, a premalignant lesion. Stromal activated myofibroblasts known as cancer-associated fibroblasts have an active role in the initiation and progression of the cancers via secretion of different molecules including matrix metalloproteinases. AIMS: This study is designed to understand the differences in the presence of myofibroblasts and expression of matrix metalloproteinase-1 in the adjacent stroma of verrucous carcinoma and oral verrucous hyperplasia (OVH). SETTINGS AND DESIGN: Cross-sectional study. MATERIAL AND METHODS: Twenty-seven OVH, 19 oral verrucous carcinoma (OVC), and 8 cutaneous verrucous carcinoma (CVC) specimens were analyzed for immunohistochemical (IHC) expression of α-smooth muscle actin (αSMA) and MMP-1. RESULTS: IHC studies for αSMA expression in nonvascular stromal cells of the adjacent stroma revealed mild or no expression in 81.4%, 73.7%, and 62.5% of the cases of OVH, OVC, and CVC groups, respectively. No significant difference was seen in αSMA expression index between OVH and OVC groups (Adj. Sig. = 0.220) and between OVC and CVC groups (Adj. Sig. = 1.00). Pairwise analysis revealed a significant difference in MMP-1 expression index between the groups. No significant correlation was observed between MMP-1 expression index and αSMA expression index in OVH (pv = 0.358) and OVC (pv = 0.388) groups. CONCLUSION: The differences in MMP-1 expression between OVH and OVC can be used as an adjunctive aid in challenging cases including disoriented or inadequate samples.

Expression of epidermal growth factor receptor in oral and esophageal squamous-cell carcinoma.

BACKGROUND: Squamous-cell carcinoma (SCC) represents the most common type of malignancies in the oral cavity (O) and esophagus (E). Epidermal growth factor receptor (EGFR) plays a key role in numerous processes that affects tumor growth, progression, differentiation, invasion, metastasis, and inhibition of apoptosis. In this study, we wanted to investigate the EGFR expression in OSCC and ESCC cases. As well, another purpose was to observe if there exists any relation between its expression and clinicopathologic factors. To the best of our knowledge, this is the first study which compares the EGFR protein expression between OSCC and ESCC. MATERIALS AND METHODS: This cross-sectional study was performed on 46 paraffin blocks (23 OSCC and 23 ESCC). The expression of EGFR was evaluated with immunohistochemical technique. Data analyses were done using SPSS software by Fisher's exact test. Significance was assigned at P < 0.05. RESULTS: Out of 46 patients, 25 cases (54.3%) were male and 21 (45.7%) were female. Seventy-eight percent of OSCCs and 73.9% of ESCCs showed high expression of EGFR. No statistically significant difference was observed between the two groups (P = 0.73). There were no statistically significant correlations between EGFR expression and clinicopathologic factors (age, gender, grade, and stage) of OSCCs (P > 0.05). A statistically significant correlation was found between EGFR expression and stage in ESCCs group (P = 0.006). CONCLUSION: No significant correlation was found between the expression of EGFR protein in OSCCs and ESCCs. High expression of EGFR was observed in ESCCs with Stages II, III.

Epithelial-Myoepithelial Carcinoma of the Palate: Report of a Case and Review of the Literatures.

Epithelial-myoepithelial carcinoma (EMC) is considered as a rare malignant salivary gland neoplasm with good prognosis, low recurrence rate and rare metastasis. Here we present a case of epithelial-myoepithelial carcinoma in a 42-year-old female with a swelling of 3-year duration in her palate. Histopathologic evaluation of the lesion demonstrated a well-circumscribed, biphasic salivary gland tumor composed of double-layered ductal/glandular structures, composed of small luminal eosinophilic cells and abluminal larger clear myoepithelial cells, and luminal cells were positive for pan-cytokeratin, while the abluminal cells exhibited strong immunoreactivity for p63. Ki-67 proliferative index was 1% in abluminal cells. In this article, histopathologic and immunohistochemical features of EMC and its mimics are discussed and the previously reported cases of EMC in the literature are summarized.

Evaluation of Cyclin D1 Expression in Aggressive and Nonaggressive Central Giant Cell Granuloma of the Jaws.

STATEMENT OF THE PROBLEM: Central giant cell granuloma of the jaws is comprised of two types namely aggressive and nonaggressive. Controversy exists regarding the histogenesis of this lesion. Up to now, there are no reliable histologic or molecular methods to differentiate aggressive from nonaggressive central giant cell granuloma of the jaw. Moreover, because of different treatment of two groups, correct diagnosis is needed. PURPOSE: The purpose of this study was to evaluate and compare the expression of cyclin D1 between aggressive and nonaggressive central giant cell granulomas of the jaws. MATERIALS AND METHOD: This retrospective study was performed on 16 paraffin blocks of aggressive central giant cell granuloma, and 16 nonaggressive central giant cell granulomas from Shahid Beheshti Oral Pathology Department and evaluated the expression of cyclin D1 on giant cells and mononuclear cells of the lesions. T-test was used for quantitative evaluation and comparison of cyclin D1 expression between two groups. RESULTS: Overexpression of cyclin D1 in giant cells and mononuclear cells of the lesions of both groups was apparent, but no significant statistical difference was seen. Cyclin D1 positivity was seen predominantly in the nuclei of giant cells. When a giant cell was positive, all the nuclei showed immunoreactivity. In each group mean percentage of the positive giant cells were higher than positive mononuclear cells and significant statistical difference (p= 0.000) was seen between them. CONCLUSION: Probably overexpression of cyclin D1 implicates in the pathogenesis of the central giant cell granulomas but it seems that this protein could not be used as a marker for identifying the clinical behavior of these lesions.

Demographic Profile of Non-Odontogenic Jaw Lesions in an Iranian Population: A 30-Year Archive Review.

OBJECTIVES: The frequency of non-odontogenic lesions of the jawbones is lower than that of odontogenic lesions; however, study of the epidemiologic data of these lesions is required for health care programs. This study aimed to assess the relative frequency and demographic profile of non-odontogenic jaw lesions in an Iranian population over a 30-year period. MATERIALS AND METHODS: This archive review was performed using demographic and biopsy information of all patients with non-odontogenic lesions of the jawbones submitted to the Oral Pathology Department of Dental School of Tehran University of Medical Sciences from 1984 to 2014. Demographic data included in the study were: age at diagnosis, gender and location of lesion. The lesions were divided into three groups of group 1: cystic lesions, group 2: tumors and tumor-like lesions, and group 3: infectious/inflammatory/reactive lesions. Frequency and clinical data were analyzed using SPSS 22. RESULTS: Of 972 non-odontogenic jaw lesions, the ratio of mandibular to maxillary lesions was 1.63:1. Female to male ratio was 1.33:1 and the mean age of patients was 29.09±16.90 years. The most common non-odontogenic jaw lesion was central giant cell granuloma (CGCG). In groups 1, 2 and 3, nasopalatine duct cyst, CGCG, and osteomyelitis were the most frequent lesions, respectively. CONCLUSIONS: Non-odontogenic lesions of the jawbones are a diverse group of lesions with different frequency and behavior. This study demonstrated that tumors and tumor-like lesions of the jaws were more common than cystic and infectious/inflammatory/reactive lesions. Overall, the most common non-odontogenic jaw lesion was CGCG.

Distraction osteogenesis for cleft palate closure: A finite element analysis.

BACKGROUND: Current methods of closure of the cleft palate result in the formation of scars and impairment of growth. Distraction osteogenesis (DO) might be an effective means to repair or at least reduce the size of wide clefts. This study investigates the biomechanical aspects of this process. MATERIALS AND METHODS: DO simulation was applied to reduce the size of a unilateral hard palate cleft on a three-dimensional (3D) model of the maxilla. For the position of osteotomy lines, two different models were assumed, with the osteotomy line on the affected side in model A and on the intact side in model B. In each model, DO screws were placed on two different positions, anteriorly (models A1 and B1) and posteriorly (models A2 and B2). Displacement pattern of the bony island in each of the four models, reaction forces at DO locations, and von Mises stress were estimated. Mesh generation and data processing were carried out in the 3D finite element analysis package (ABAQUS V6.7-1; Simulia Corp., Providence, RI, USA). RESULTS: In model B2, the island moved almost evenly, assuring a more complete closure of the cleft. The most uniform stress distribution was found in model B1. CONCLUSION: The results suggest that the best positions for the DO screw and the osteotomy line for closure of the cleft palate are posteriorly and on the intact side, respectively.

Predictive factors of potential malignant transformation in recurrent calcifying cystic odontogenic tumor: review of the literature.

Calcifying cystic odontogenic tumor (CCOT) demonstrates considerable diversity in histopathology and clinical behavior. Ghost cell odontogenic carcinoma (GCOC) is the rare malignant counterpart of CCOT and it frequently arises from malignant transformation of a recurrent CCOT. In this paper, we present a case of CCOT and discuss its distinct histopathologic features in recurrence. Then, we will have a review on clinical, histopathological, and immunohistochemical aspects of GCOC in the literature. Predictive factors of malignant transformation in a benign CCOT will also be discussed.