Focal adhesion kinases in head and neck squamous cell carcinoma.

BACKGROUND: Focal adhesion kinase (FAK) phosphorylation contributes to the regulation of growth factors that promote cellular adhesion, mobility, and survival, being a key factor in tumor development. The objective of this study was to evaluate the immunohistochemical expression patterns of FAK and its phosphorylated forms, FAK Tyr-576 and FAK Tyr-925, in head and neck squamous cell carcinoma and non-neoplastic adjacent epithelial tissue (AE). METHODS: The percentage of immunohistochemistry stained cells and its correlation with clinicopathological variables and prognosis were determined using samples from 54 patients. RESULTS: FAK, FAK Tyr-576, and FAK Tyr-925 overexpression was observed in tumor zones and AE. FAK Tyr-576 immunostaining showed a relationship with tumor clinicopathological parameters. Moreover, positive immunostaining of FAK Tyr-576 in AEsue was associated with patients prognoses. CONCLUSIONS: Increased expression of FAK Tyr-576 could enable identification of tumors with a more aggressive behavior and epithelial alterations before the appearance of clinical or histological manifestations.

TGF-ß1 and its association with clinicopathological features, proliferative activity and prognosis in oral squamous cell carcinoma: an immunohistochemical study

Introduction: The prognostic value of transforming growth factor beta-1 (TGF-ß1) in oral cancer remains unclear. Therefore, the aim of this study was to evaluate TGF-ß1 expression in oral squamous cell carcinoma (OSCC) samples and its association with clinicopathological data, tumor proliferative activity, and patients' prognosis. Methods: A total of 68 patients with histopathological diagnosis of OSCC were included, as well as 9 cases of normal oral mucosa for comparison purposes. The OSCC sample was categorized according to patients' outcomes in favorable prognosis (n=30) or unfavorable prognosis (n=38). Immunohistochemical staining for TGF-ß1 and Ki-67 were performed. The slides were semi-quantitatively and quantitatively evaluated for TGF-ß1 and Ki-67, respectively. Results: TGF-ß1 was significantly increased in OSCC compared to normal oral mucosa (<0.01). An inverse correlation was found between TGF-ß1 and Ki67 staining in OSCC (p=0.01). No association was found between TGF-ß1 expression and OSCC clinicopathological features, prognosis or survival. Conclusions: TGF-ß1 had no prognostic value and appears to maintain its suppressive role concerning cell proliferation. (AU)

Analysis of the Epithelium-Mesenchymal Transition Process on Oral Squamous Cell Carcinomas

Abstract The aim of this study is to evaluate the immunohistochemical expression of E-cadherin, N-cadherin and Bmi-1, and their association with clinical parameters and with the degree of histopathological differentiation in oral squamous cell carcinomas. 65 squamous cell carcinoma samples were used for constructing a tissue microarray block, and then immunohistochemistry was performed for different markers. A semi-quantitative analysis of the amount of positive tumor cells was performed by two blind and calibrated observers (Kappa>0.75). The statistical Mann-Whitney and Kruskal-Wallis tests were used to evaluate the data. The correlation between variables was investigated by the Spearman test, and the significance level set at p<0.05. We observed higher expression of Bmi-1 in tumors located in the palate (p<0.0001). In addition, poorly differentiated tumors had a greater amount of Bmi-1 positive cells (p=0.0011). Regarding the other correlations between variables, no significant associations were detected. In conclusion, poorly differentiated squamous cell carcinomas located in the palate have higher immunostaining of Bmi-1, which can characterize activation of the Epithelial-Mesenchymal Transition process in these tumors.

Resumo O objetivo deste estudo foi avaliar a associação entre a expressão imunoistoquímica de E-caderina, N-caderina e Bmi-1, com os parâmetros clínicos e o grau de diferenciação em carcinomas espinocelulares bucais. Sessenta e cinco amostras foram selecionadas para a construção de um bloco de microarranjo tecidual, e a técnica de imunoistoquímica foi realizada para os diferentes marcadores. Uma análise semi-quantitativa das células tumorais positivas foi realizada por dois observadores calibrados e cegos (Kappa>0.75). Os testes estatísticos Mann-Whitney e Kruskal-Wallis foram utilizados para a análise dos dados e a correlação entre as variáveis foi investigada com o teste de Spearman. O nível de significância foi determinado em p <0.05. Observamos maior expressão de Bmi-1 em tumores localizados em palato (p <0.0001). Além disso, tumores pobremente diferenciados apresentaram maior quantidade de células positivas para Bmi-1 (p=0.0011). Não encontramos outras correlações ou associações significativas. Em conclusão, carcinomas espinocelulares pobremente diferenciados e localizados no palato apresentam maior marcação imunoistoquímica de Bmi-1, o que pode caracterizar a ativação do processo de transição epitélio-mesênquima nesses tumores.

Angina bullosa hemorrhagica: report of 7 cases and analysis of 199 cases from the literature.

Angina bullosa hemorrhagica (ABH) is a condition characterized by blood blisters in the oral or oropharyngeal mucosa. Typically, the first presentation of ABH is acute, and rupture of the blisters occurs after a few hours or days. Although its etiology is unclear, ABH is assumed to be associated with predisposing factors such as local trauma or chronic use of inhaled steroids. The diagnosis is defined clinically, based on the presentation and evolution of the lesions. The recommended treatment is symptomatic, but extensive lesions may present a risk of airway obstruction and may require surgical excision. This case series reports 7 cases of ABH and reviews 199 cases published in the English-language literature. The possible etiologic factors, predisposing factors, and differential diagnoses are discussed.

Predictive value of p63, ki-67, and survivin expression in oral leukoplakia: A tissue microarray study.

The aim of this study was to analyze the immunohistochemical expression of survivin, ki-67, and p63 in oral leukoplakic lesions, histopathologically differentiated into dysplastic and nondysplastic. A tissue microarray containing 57 samples of biopsies from clinically classified lesions, such as leukoplakia, was immunolabeled for survivin, ki-67, and p63. Samples were scored for percentage of positively stained. Scores were designated as follows: low = less than 25% of positive cells; and high = more than 25% of positive cells. On performing histopathological diagnosis, 20 dysplastic lesions and 37 nondysplastic lesions were seen, in which female patients (56.1%) were predominant with an average age of 58.27 years. The study showed a high expression of 37.5% for survivin, 43.7% for ki-67, and 88.2% for p63 in dysplastic lesions. However, there was a high expression of 16.7% for survivin, 16.7% for ki-67, and 92% for p63 in nondysplastic lesions. There is a positive correlation of expression among the three antibodies. In the association of immunoreactivity, in both dysplastic and nondysplastic lesions, increased expression of survivin reflects on the increased expression of ki-67, and there is an overexpression of p63. In leukoplakia, the expression of survivin associated with that of ki-67 reinforces the assumption that all these lesions are potentially malignant, regardless of histopathology; and the overexpression of p63 may indicate carcinogenic potential. These findings may help in the treatment of patients with this type of lesion.

Therapeutic Inhibition of the MDM2-p53 Interaction Prevents Recurrence of Adenoid Cystic Carcinomas.

Purpose: Conventional chemotherapy has modest efficacy in advanced adenoid cystic carcinomas (ACC). Tumor recurrence is a major challenge in the management of ACC patients. Here, we evaluated the antitumor effect of a novel small-molecule inhibitor of the MDM2-p53 interaction (MI-773) combined with cisplatin in patient-derived xenograft (PDX) ACC tumors.Experimental Design: Therapeutic strategies with MI-773 and/or cisplatin were evaluated in SCID mice harboring PDX ACC tumors (UM-PDX-HACC-5) and in low passage primary human ACC cells (UM-HACC-2A, -2B, -5, -6) in vitro The effect of therapy on the fraction of cancer stem cells (CSC) was determined by flow cytometry for ALDH activity and CD44 expression.Results: Combined therapy with MI-773 with cisplatin caused p53 activation, induction of apoptosis, and regression of ACC PDX tumors. Western blots revealed induction of MDM2, p53 and downstream p21 expression, and regulation of apoptosis-related proteins PUMA, BAX, Bcl-2, Bcl-xL, and active caspase-9 upon MI-773 treatment. Both single-agent MI-773 and MI-773 combined with cisplatin decreased the fraction of CSCs in PDX ACC tumors. Notably, neoadjuvant MI-773 and surgery eliminated tumor recurrences during a postsurgical follow-up of more than 300 days. In contrast, 62.5% of mice that received vehicle control presented with palpable tumor recurrences within this time period (P = 0.0097).Conclusions: Collectively, these data demonstrate that therapeutic inhibition of MDM2-p53 interaction by MI-773 decreased the CSC fraction, sensitized ACC xenograft tumors to cisplatin, and eliminated tumor recurrence. These results suggest that patients with ACC might benefit from the therapeutic inhibition of the MDM2-p53 interaction. Clin Cancer Res; 23(4); 1036-48. ©2016 AACR.

Effect of different presentations of resveratrol on cell proliferation and epitelial thickness of the oral mucosa of wistar rats

Introduction: Grape is one of the most important fruit crops across the world and can be consumed in different ways. There has been a growing interest in the role of antioxidants such as resveratrol, which can be found in grape skin, in oral and dental tissues. Thus, the objective of this study was to analyze the effect of different presentations of resveratrol on cell proliferation and epithelial thickness of the oral mucosa of Wistar rats. Methods: Fifty male Wistar rats were randomly divided into five groups: water/control, red wine, grape juice, 12% alcoholic solution/ethanol and aqueous solution of resveratrol. Samples of palatal and tongue mucosa were collected for a histomorphometric analysis using hematoxylin-eosin staining and the argyrophilic nucleolar organizer region (AgNOR) technique for quantification of cell proliferation. Results: As to epithelial thickness, both the tongue and the palate showed a statistically significant difference between the control group and the other groups, with greater decrease in the resveratrol and the wine groups. In the suprabasal layer of both the tongue and the palate epithelium, red wine reduced the rate of cell proliferation, while ethanol increased it. In the basal layer of the tongue epithelium, there was a statistically significant difference between the control, the grape juice and the resveratrol groups and the ethanol group, with increased cell proliferation in the ethanol group. Conclusions: Wine does not interfere in the physiological renewal of the basal layer of the buccal epithelium and exerts a protective action by reducing the cell proliferation rate of the suprabasal layer (AU)

Fibronectin Modulates Cell Adhesion and Signaling to Promote Single Cell Migration of Highly Invasive Oral Squamous Cell Carcinoma.

Cell migration is regulated by adhesion to the extracellular matrix (ECM) through integrins and activation of small RhoGTPases, such as RhoA and Rac1, resulting in changes to actomyosin organization. During invasion, epithelial-derived tumor cells switch from laminin-enriched basal membrane to collagen and fibronectin-enriched connective tissue. How this switch affects the tumor migration is still unclear. We tested the hypothesis that ECM dictates the invasiveness of Oral Squamous Cell Carcinoma (OSCC). We analyzed the migratory properties of two OSCC lines, a low invasive cell line with high e-cadherin levels (Linv/HE-cad) or a highly invasive cell line with low e-cadherin levels (Hinv/LE-cad), plated on different ECM components. Compared to laminin, fibronectin induced non-directional collective migration and decreased RhoA activity in Linv/HE-cad OSCC. For Hinv/LE-cad OSCC, fibronectin increased Rac1 activity and induced smaller adhesions, resulting in a fast single cell migration in both 2D and 3D environments. Consistent with these observations, human OSCC biopsies exhibited similar changes in cell-ECM adhesion distribution at the invasive front of the tumor, where cells encounter fibronectin. Our results indicate that ECM composition might induce a switch from collective to single cell migration according to tumor invasiveness due to changes in cell-ECM adhesion and the resulting signaling pathways that alter actomyosin organization.

Ameloblastic neoplasia spectrum: a cross-sectional study of MMPS expression and proliferative activity.

OBJECTIVE: To compare the proliferation and the expression of matrix metalloproteinases (MMPs; MMP-2 and MMP-9) in solid and unicystic ameloblastomas with ameloblastic carcinomas. STUDY DESIGN: Five cases of ameloblastic carcinoma (AC), 18 cases of solid ameloblastoma (SA), and seven of unicystic ameloblastoma (UA) were selected. The immunohistochemical expression of MMPs was assessed by the percentage of positive tumor cells and stained stroma. The mean argyrophilic nucleolar organizer region (AgNOR) and the percentage of cells with more than one AgNOR per nucleus were evaluated. RESULTS: Statistically significant higher mean AgNOR was observed in AC than in SA and UA. MMP-2 was expressed similarly in tumor and stroma among groups. MMP-9 was higher in the stroma of SA than that of UA (P = .0484). CONCLUSIONS: The cell proliferation was related to the greater aggressiveness of AC. High expression of MMP-2 and MMP-9 in all lesions highlighted the importance of these enzymes in the biology of ameloblastic tumors.

Agreement between clinical and histopathologic diagnoses and completeness of oral biopsy forms

Abstract The present study aimed to assess the rate of agreement between clinical and histopathological diagnoses and to report the frequency of completed forms for specimens that were subjected to histopathological examination and retrospectively examined. Data from 8,168 specimens submitted to histopathological examination were retrieved from the records. A total of 5,368 cases were included. Agreement was defined based on the definition of lesion nature according to its diagnostic category. Sensitivity, specificity, and positive and negative predictive values were calculated for each diagnostic category. The highest rate of agreement was observed for periapical lesions (92.6%), followed by potentially malignant disorders (90.1%) and non-neoplastic proliferative disorders (89.3%). Low rates of histopathological confirmation of the clinical impression were observed for mesenchymal tumors (25.0%) and cysts (44.2%). Sensitivity values were > 0.70 for all lesions, except for cysts (0.51). Specificity was relatively high, ranging from 0.97 to 1.00. The frequency of incomplete biopsy forms ranged from 16.8% (malignant tumors of oral mucosal epithelium) to 51.0% (nonspecific inflammatory reaction). The most frequently completed biopsy forms corresponded to epithelial malignant tumors (83.2%) and glandular inflammation (72.3%). In conclusion, there was an acceptable level of agreement. The low level of completeness of biopsy forms indicates little awareness about the relevance of gathering detailed information during clinical examination.

Location of injected polymethylmethacrylate microspheres influences the onset of late adverse effects: an experimental and histopathologic study.

Polymethylmethacrylate (PMMA) has been widely used in the correction of wrinkles because of its long-lasting cosmetic improvements. However, side effects and complications may occur, and its clinical appearance on the oral mucosa can be similar to that of inflammatory or neoplastic disease. The aim of this research was to compare the clinical and histopathologic responses to PMMA injected by two different methods. Twenty-two rats received an injection of PMMA using the tunneling technique (gold standard), with subcutaneous deposition of the filler in the face, or a variation of the technique with transcutaneous submucosal deposition of the filler in the cheek. The tissue reaction was analyzed clinically every 24 hours during the first week, then once a week for the following 3 months. Histologic evaluation was based on the local inflammatory response to the filler. No clinical changes were observed during the initial evaluation period (0-14 days). After 14 days, only the submucosal group showed extra-oral enlargement (n=4, 18.2%). Histopathologic analysis revealed nodule formation in four animals (18.2%) in the submucosal group, with no nodules observed in the subcutaneous group. The data obtained in this study demonstrate that the technique used to deliver the filler may influence the risk of adverse reactions.

Oral mucosal lesions and their association with sociodemographic, behavioral, and health status factors.

The aim of this study was to evaluate the frequency of oral mucosal lesions and their associations with sociodemographic, health, and behavioral factors in a southern Brazilian population. Information was collected from participants (n = 801) using a structured questionnaire during an oral cancer screening campaign held at an agribusiness show in southern Brazil in 2009. Data were described using frequency distributions or means and standard deviations. Associations between independent variables and outcomes were assessed using the Chi-squared test. A total of 465 lesions were detected (actinic cheilitis: n = 204, 25.5%; candidiasis: n = 50, 6.2%; fibrous inflammatory hyperplasia: n = 42, 5.2%; ulceration, n = 33, 4.1%; hemangioma: n = 14, 1.7%; leukoplakia: n = 11, 1.4%). Candidiasis, actinic cheilitis, and fibrous inflammatory hyperplasia were associated significantly with literacy. Actinic cheilitis was also associated significantly with sun exposure and hat use, and leukoplakia was associated with smoking. The high frequency of oral mucosal lesions observed highlights the importance of education about risk factors. Additionally, training of health professionals, mainly those from public health services, in the use of preventive and community education strategies is needed.

Relationship between the positions of impacted third molars and the presence of dentigerous cysts.

The objective of this study was to assess the association between the histopathological diagnoses of dentigerous cysts and pericoronal follicles and the positions of impacted third molars. The sample comprised 151 cases, diagnosed as dentigerous cysts and pericoronal follicles. Most patients were female (70.9%), white (90.1%), and age 20 years or older (63.6%). Ninety-eight cases (64.9%) were diagnosed as pericoronal follicles and 53 (35.1%) as dentigerous cysts. Teeth that developed dentigerous cysts were predominantly located in the mandible (84.9%), in a mesioangular position (49.1%), and in the 20- to 29-year age group (66.0%). The mandible seems to be the most frequent location of impacted teeth, probably because mandibular tooth eruption is more difficult, as well as dentigerous cysts, probably because the long duration of impaction increases the exposure to inflammatory stimuli and, thus, the potential for formation of dentigerous cysts. The findings also suggest that the incidence of dentigerous cysts tends to increase with age, especially for mandibular teeth in mesioangular positions.

A 10-year analysis of the oral squamous cell carcinoma profile in patients from public health centers in Uruguay.

The aim of this study was to evaluate the demographic, clinical, and therapeutic characteristics and predictive factors of poor prognosis in patients with primary oral squamous cell carcinoma (OSCC) in Uruguay. Medical records of patients with the diagnosis of primary OSCC treated between 2000 and 2010 in Uruguayan public hospitals were selected. Data on demographic characteristics, risk factors, clinical features, treatment, and outcome were collected. Associations of independent variables with outcomes were assessed using Pearson chi-squared and Fisher's tests. Of 200 patients with OSCC, 79.4% were men (3.8:1 male:female ratio), with a mean age of 60.75 ± 11.26 years. Tobacco and alcohol consumption were reported by 85.3% and 63.5% of patients, respectively. The most commonly affected location was the tongue (42.5%), with lesions exhibiting ulcerous aspects in 87.9% of cases and pain at the time of diagnosis in 70.4% of cases. One hundred sixty-one (82.1%) patients had advanced-stage (III/IV) OSCC. Surgery was the most common treatment option, and the overall 5-year survival rate was 58.5%. Univariate analysis showed that the predictors of poor prognosis were clinical aspect, size, regional metastasis, clinical stage, and treatment. In Uruguay, OSCC is diagnosed late, which is associated with a low survival rate. Educational and preventive measures and investment to improve early diagnosis should be undertaken.

Immunocytochemistry associated with oral exfoliative cytology: methodological analysis..

OBJECTIVE: To evaluate different immunocytochemical protocol variations to find the most effective protocol for the analysis of involucrin, epidermal growth factor receptor (EGFR), and E-cadherin antibodies. Exfoliative cytology is a noninvasive method used to monitor and screen for early changes in the oral mucosa of patients exposed to carcinogens such as tobacco and alcohol. It has been postulated that its association with immunocytochemistry may improve the effectiveness of the screening process. STUDY DESIGN: Four graduate students from Porto Alegre in southern Brazil had oral smears collected from the border of the tongue using a cytobrush. The following variables were analyzed: cell membrane permeability, antigen retrieval method (microwave oven or water bath), antibody incubation time (overnight or 1 hour), detection system used (Envision or LSAB), and chromogen incubation time (10 seconds or 5 minutes). RESULTS: Best results were obtained with the following combinations: (1) for involucrin: water bath, 1-hour incubation for primary antibody, Envision, and chromogen incubation for 10 seconds; (2)for EGFR: microwave, overnight incubation, LSAB, and chromogen incubation for 5 minutes; and (3) for E-cadherin: water bath, over-night incubation, Envision, and chromogen incubation for 5 minutes. CONCLUSION: Our findings suggest that each antibody requires a specific immunocytochemical protocol to guarantee optimal results with oral smears.

The importance of histopathologic analysis of pericoronal follicles for the early identification of ameloblastomas.

The objective of this study was to discuss the importance of performing histopathological examination of pericoronal follicles as a routine procedure, so as to enable the early identification of odontogenic lesions. We describe two clinical cases with histopathological diagnoses of ameloblastomas who did not show clinical or radiographic signs of disease before microscopic examination.

A 10-year analysis of the oral squamous cell carcinoma profile in patients from public health centers in Uruguay

The aim of this study was to evaluate the demographic, clinical, and therapeutic characteristics and predictive factors of poor prognosis in patients with primary oral squamous cell carcinoma (OSCC) in Uruguay. Medical records of patients with the diagnosis of primary OSCC treated between 2000 and 2010 in Uruguayan public hospitals were selected. Data on demographic characteristics, risk factors, clinical features, treatment, and outcome were collected. Associations of independent variables with outcomes were assessed using Pearson chi-squared and Fisher's tests. Of 200 patients with OSCC, 79.4% were men (3.8:1 male:female ratio), with a mean age of 60.75 ± 11.26 years. Tobacco and alcohol consumption were reported by 85.3% and 63.5% of patients, respectively. The most commonly affected location was the tongue (42.5%), with lesions exhibiting ulcerous aspects in 87.9% of cases and pain at the time of diagnosis in 70.4% of cases. One hundred sixty-one (82.1%) patients had advanced-stage (III/IV) OSCC. Surgery was the most common treatment option, and the overall 5-year survival rate was 58.5%. Univariate analysis showed that the predictors of poor prognosis were clinical aspect, size, regional metastasis, clinical stage, and treatment. In Uruguay, OSCC is diagnosed late, which is associated with a low survival rate. Educational and preventive measures and investment to improve early diagnosis should be undertaken.

Efficacy of laser phototherapy in comparison to topical clobetasol for the treatment of oral lichen planus: a randomized controlled trial.

Oral lichen planus (OLP) is a relatively common chronic mucocutaneous inflammatory disease and a search for novel therapeutic options has been performed. We sought to compare the efficacy of laser phototherapy (LPT) to topical clobetasol propionate 0.05% for the treatment of atrophic and erosive OLP. Forty-two patients with atrophic/erosive OLP were randomly allocated to two groups: clobetasol group (n=21): application of topical clobetasol propionate gel (0.05%) three times a day; LPT group (n=21): application of laser irradiation using InGaAlP diode laser three times a week. Evaluations were performed once a week during treatment (Days 7, 14, 21, and 30) and in four weeks (Day 60) and eight weeks (Day 90) after treatment. At the end of treatment (Day 30), significant reductions in all variables were found in both groups. The LPT group had a higher percentage of complete lesion resolution. At follow-up periods (Days 60 and 90), the LPT group maintained the clinical pattern seen at Day 30, with no recurrence of the lesions, whereas the clobetasol group exhibited worsening for all variables analyzed. These findings suggest that the LPT proved more effective than topical clobetasol 0.05% for the treatment of OLP.

Spatial distribution of cancer stem cells in head and neck squamous cell carcinomas.

BACKGROUND: CD44 and aldehyde dehydrogenase 1 (ALDH1) are considered putative markers of highly tumorigenic cells (i.e., cancer stem-like cells) in head and neck squamous cell carcinomas. This small subset of cells is believed to be the primary responsible for tumor initiation and progression. The objectives of this study were (i) to evaluate the patterns of CD44 and ALDH1 expression in the tumor center and in the invasive front, as well as in adjacent non-tumor epithelium, and (ii) to correlate these findings with clinical parameters. MATERIALS AND METHODS: The sample comprised 44 patients with primary head and neck squamous cell carcinomas. Hematoxylin and eosin (HE) staining was used for histopathological tumor grading and for morphological analysis of adjacent non-tumor epithelium. Semiquantitative analysis was performed in histological sections immunostained for CD44 and ALDH1. RESULTS: ALDH1 immunostaining in the invasive front showed positive association with tumor size, regional metastasis, tumor histopathological grading, and disease progression. Moreover, expression of this marker in both tumor invasive front and adjacent non-tumor epithelium was related with more aggressive tumors. CD44 immunostaining was heterogeneous in all areas evaluated and did not show association with clinical data. CONCLUSION: Collectively, these data suggest that ALDH1 immunostaining in the invasive front and in adjacent non-tumor epithelium may help identify tumors with a more aggressive behavior, potentially contributing to improving treatment customization and the monitoring of patients with head and neck cancer.

Analysis of the proliferative potential of odontogenic epithelial cells of pericoronal follicles.

AIM: To evaluate the proliferative potential and the cell proliferation rate of odontogenic epithelial cells. MATERIALS AND METHODS: Forty-two cases of pericoronal follicles of impacted third molars were submitted to silver impregnation technique for quantification of argyrophilic nucleolar organizer regions (AgNOR) and immunohistochemical staining for EGFR and Ki-67. For AgNOR quantification, the mean number of active nucleolar organizer regions per nucleus (mAgNOR) and the percentage of cells with 1, 2, 3 and 4 or more AgNORs per nucleus (pAgNOR) were quantified. Ki-67 immunolabeling was quantified, whereas for EGFR, a descriptive analysis of staining patterns (membrane, cytoplasm or membrane + cytoplasm positivity) was performed. We evaluated the reduced epithelium of the enamel organ and/or islands of odontogenic epithelium present in the entire connective tissue. RESULTS: mAgNOR were 1.43 (1.0-2.42) and were significantly different among pericoronary follicles from upper and lower teeth (p = 0.041). Immunostaining of Ki-67 was negative in all cases. EGFR immunolabeling was found mainly in the cytoplasm and was more intense in islands and cords when compared to reduced epithelium of the enamel organ. CONCLUSION: Odontogenic epithelial cells of some pericoronal follicles have proliferative potential, suggesting their association with the development of odontogenic lesions. CLINICAL SIGNIFICANCE: The authors suggest that nonerupted, especially of the lower teeth, should be monitored and if necessary removed.