Oral manifestations of amyloidosis and the diagnostic applicability of oral tissue biopsy.

BACKGROUND: Amyloidosis exhibits a variable spectrum of systemic signs and oral manifestations that can be difficult to diagnose. This study aimed to characterize the clinical, demographic, and microscopic features of amyloidosis in the oral cavity. METHODS: This collaborative study involved three Brazilian oral pathology centers and described cases with a confirmed diagnosis of amyloidosis on available oral tissue biopsies. Clinical data were obtained from medical records. H&E, Congo-red, and immunohistochemically stained slides were analyzed. RESULTS: Twenty-six oral biopsies from 23 individuals (65.2% males; mean age: 59.6 years) were included. Oral involvement was the first sign of the disease in 67.0% of cases. Two patients had no clinical manifestation in the oral mucosa, although the histological analysis confirmed amyloid deposition. Amyloid deposits were distributed in perivascular (88.0%), periacinar and periductal (80.0%), perineurial (80.0%), endoneurial (33.3%), perimuscular (88.2%), intramuscular (94.1%), and subepithelial (35.3%) sites as well as around fat cells (100.0%). Mild/moderate inflammation was found in 65.4% of cases and 23.1% had giant cells. CONCLUSIONS: Amyloid deposits were consistently found in oral tissues, exhibiting distinct deposition patterns. Oral biopsy is less invasive than internal organ biopsy and enables the reliable identification of amyloid deposits even in the absence of oral manifestations. These findings corroborate the relevance of oral biopsy for the diagnosis of amyloidosis.

Rhabdomyosarcoma of the oral cavity in children aged 0-2 years: A scoping review.

BACKGROUND: The aim of this study was to collect, synthesize, and analyze the clinic-demographic data of rhabdomyosarcoma affecting the oral cavity of young children. METHODS: The clinical question was "What are the clinical characteristics of oral rhabdomyosarcoma in children aged zero to two years?" Two independent reviewers selected the studies, extracted data, and assessed the methodological quality through the Joanna Briggs Institute Checklist. Descriptive statistics were performed in SPSS. (protocol: osf.io/b9hvy). RESULTS: Thirty case reports with 41 patients were included (22 males; mean age at diagnosis: 15 months). All studies had some methodological limitations, mainly due to the lack of clarity for a final judgment. More than 70% of the cases affected the tongue or lips. Tumors had a fast growth (mean 2.5 months), usually with red coloration, and variable shape and consistency. Embryonal (63.41%) and alveolar (29.27%) were the most common histological subtypes. Treatment was quite variable but usually included surgery. Most patients (53.66%) were alive without disease at follow-up. CONCLUSION: Oral rhabdomyosarcoma is rare in children aged 0-2 years without a marked gender predilection. The tumor presents as a fast and infiltrative growth leading to local and/or systemic symptoms, and a favorable prognosis for most patients.

Oral melanoacanthoma: Clinicopathological and immunohistochemical features of a case series and a scoping review.

BACKGROUND: This study presents a case series and scoping review of oral melanoacanthoma to examine its clinical, histopathological, and immunohistochemical characteristics. METHODS: Nine cases of oral melanoacanthoma were included in the case series. Clinical data were collected from biopsy charts. Hematoxylin-eosin and immunohistochemistry for TRP2, CD3, and CD20 were done. For the scoping review, MEDLINE/PubMed, Web of Science, EMBASE, and Scopus were searched. RESULTS: Case series: The mean age was 46.8 years (female-to-male ratio 2:1). Lesion's mean size was 11.0 mm (±9.3). Lesions were mainly macular (77.8%) with brown or black coloration (88.9%) and often affected multiple sites (44.4%). The evolution time ranged from 15 days to 96 months. Lesions commonly showed epithelial acanthosis (66.7%), spongiosis (55.6%), exocytosis (77.8%), melanin incontinence (88.9%), and inflammatory infiltrate in the lamina propria (77.8%), from which all showed lymphocytes. TRP2-positive melanocytes were identified in the basal and spinous layer of all cases, and in the superficial layer of three cases. CD3-positive cells predominate over the CD20-positive. Scoping review: 85 cases of oral melanoacanthoma were retrieved from 55 studies. Patients were primarily female (female-to-male ratio 2.2:1), black-skinned (64.1%), with a mean age of 36.13 (± 17.24). Lesions were flat (81.9%), often brown (62.4%). Buccal mucosa was the preferred site (32.9%), followed by multiple sites (28.2%). CONCLUSION: Oral melanoacanthoma mainly affects women across a wide age range, with lesions commonly appearing as brown/black macules, particularly on the buccal mucosa. TRP2-positive melanocytes and T-lymphocytes were consistently found and could participate in oral melanoacanthoma pathogenesis.

Impact of the COVID-19 pandemic on public University laboratories of oral and maxillofacial pathology: A Brazilian multicenter study.

OBJECTIVE: To evaluate the impact of the COVID-19 pandemic on the number of diagnoses of oral and maxillofacial lesions in public laboratories after one year of COVID-19 outbreak in Brazil. MATERIAL AND METHODS: This is a cross-sectional study. Biopsies submitted to histopathologic examination from March 2019 to February 2020 (pre-pandemic period) and from April 2020 to March 2021 (pandemic period) in nine Brazilian public oral pathology laboratories were retrieved and the number of diagnoses, types of lesion, and percentage changes during both periods were analyzed. RESULTS: There were 7389 diagnoses in the pre-pandemic period and 2728 in the pandemic era, indicating a reduction of 63.08%. The reduction was 64.23% for benign lesions and 49.48% for malignant lesions, with a 50.64% reduction in squamous cell carcinoma. The largest decreases were observed in April 2020 and January 2021. CONCLUSION: An important reduction in the diagnoses of benign and malignant lesions was noted in the Brazilian public oral pathology laboratories during the first year of the COVID-19 pandemic.

Clinicopathological and immunohistochemical features of the oral lymphoepithelial cyst: A multicenter study.

BACKGROUND: Analyze the clinical, demographic, histopathological, and immunohistochemical features of oral lymphoepithelial cyst (OLEC). METHODS: Samples were retrospectively retrieved from five oral pathology services. Clinical and demographic data were collected from patient charts. Histopathological and immunohistochemical (CD3 and CD20) features were evaluated. Data analysis involved descriptive statistics and bivariate analyses (P ≤ .05). RESULTS: Seventy-seven cases were found among a total of 146 150 specimens (0.05%). OLEC was predominantly diagnosed in females (70.1%). Mean patient age was 46.51 years. The lesions arose mainly on the lateral border of the tongue (40.3%), measured up to 1 cm (61.0%), and were asymptomatic (64.9%). Twenty-four lesions (31.2%) were white. Forty-one cases (53.2%) presented lymphocytic inflammatory infiltrate with no specific arrangement. The cystic lining was composed of a non-keratinized stratified epithelium (59.7%) presenting hyperplasia (39.0%). Connection with the surface, epithelium was found in 23 cases (29.9%) and 31 (40.3%) cases had two or more cystic cavities. The lumen content was predominantly desquamated cells (48.1%). Subgemmal neurogenous plaque was found in 11/42 (26.2%) cases involving the tongue. CD20+ cells predominated in 36/63 cases (57.2%), and lymphocytic inflammatory infiltrate was not always continuous around the cystic cavity (52.4%). CONCLUSION: Lymphoepithelial cyst is an uncommon lesion of the oral cavity. The present study offers the largest sample of OLEC for which clinical, demographic, histopathological, and immunohistochemical features were evaluated. The clinical and demographic findings were similar to those described in previous reports, but the microscopic analyses revealed interesting aspects of the cystic epithelium and the lymphocytic inflammatory infiltrate in OLEC.

Tumor depth of invasion and prognosis of early-stage oral squamous cell carcinoma: A meta-analysis.

OBJECTIVES: To assess the prognosis for early-stage oral squamous cell carcinoma according to tumor depth of invasion (DOI). METHODS: This study was logged in the PROSPERO database under protocol # CRD42017059976. The search was conducted in six electronic databases up to May 2019. Fixed-effects meta-analysis was performed for the calculation of the odds ratio (OR) and respective 95% CI. Primary outcomes were lymph node metastasis, recurrence, and survival. Heterogeneity was calculated by the I2 test. The certainty of evidence was assessed by Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. RESULTS: Twenty-seven studies were included (19 in the meta-analysis) with 2,404 patients with a mean of 60 years of age. High tumor DOI is associated with a greater chance of presenting lymph node metastasis, regardless of the cutoff point for DOI (13 meta-analysis; OR 1.69-53.08), recurrence (five meta-analysis; OR 1.22-3.83), and lower chance of survival (1 meta-analysis; OR 0.49). The certainty of evidence varied from very low to low. CONCLUSIONS: Tumor DOI is a good prognosticator for early-stage OSCC. The findings of the current meta-analysis highlight the clinical relevance of DOI and corroborate its incorporation for staging OSCC.

Immunophenotype of neutrophils in oral squamous cell carcinoma patients.

BACKGROUND: The aim was to explore the immunophenotype of neutrophils and lymphocytes and the inflammatory mediators in patients with oral squamous cell carcinoma, comparing with controls; and to associate with clinicopathological data. METHODS: Blood was collected from 13 patients and 13 controls. The immunophenotype of neutrophils (CD66b, CD16, CD11a, arginase-1), T lymphocytes (CD4, CD8) and the intracellular cytokine production (IL-10, TNF, IFN-γ) was evaluated by flow cytometry. Plasma concentration of sVCAM-1, sTNF-RI, sTNF-RII, and IL-1ß was measured by ELISA. MPO, Lipocalin-2/NGAL, sICAM-1, and p-selectin were quantified by Luminex assay. The excised tumors were submitted to immunohistochemistry for neutrophils (CD66b) and lymphocytes (CD3, CD4, CD8). Association with clinical data was explored. P values <.05 were considered significant. RESULTS: Patients presented higher percentage of neutrophils and lower lymphocytes, resulting a higher neutrophil/lymphocyte ratio than controls. They also presented higher percentage of neutrophils expressing CD66b+ , CD66b+ Arginase-1+ , CD66b+ IL10+ , CD66b+ TNF+ , CD66b+ Arginase-1+ IL-10+ , and lower CD66b+ CD16+ CD11a+ and CD66b+ Arginase-1+ TNF+ . CD66b+ neutrophils were detected in all tumors, with a CD66b+ /CD3+ ratio of 0.40. Patients showed higher concentration of plasmatic sVCAM-1 and lower Lipocalin-2/NGAL. Patients with good outcome presented lower percentage of neutrophils, higher percentage of lymphocytes, and lower NLR than patients who died. CONCLUSION: The amount and immunophenotype of neutrophils and lymphocytes differ between patients and healthy individuals, with a pro-tumorigenic profile of neutrophils. As these cells also get within tumor microenvironment, they possibly exert systemic and local functions in cancer pathogenesis. The association of neutrophil count with outcome corroborates recent studies and this merits further investigation for applicability as a prognosticator.

Metallothionein immunoexpression in non-syndromic and syndromic keratocystic odontogenic tumour.

BACKGROUND: To compare the metallothionein (MT) immunoexpression in non-syndromic and syndromic keratocystic odontogenic tumour (KOT), to correlate MT with cellular proliferation, and to evaluate the influence of inflammation in MT. STUDY DESIGN: Fourteen cases of KOT were submitted to immunohistochemistry for MT and Ki-67 analysis. The lesions were grouped according to their grade of inflammation, and statistical analysis was performed. RESULTS: MT was higher in non-syndromic KOT than in syndromic KOT (p<0.05). No statistical difference in Ki-67 could be identified; however, an inverse correlation was observed between MT and Ki-67 in both lesions. When analysing inflammation, non-syndromic KOT showed no differences in either MT or Ki-67. CONCLUSIONS: The MT immunophenotype of syndromic KOT was different from non-syndromic KOT. MT might not be involved in the proliferation control of both KOT. MT and Ki-67 immunoexpressions proved to be unaffected by inflammation in non-syndromic KOT.

Metallothionein immunoexpression in selected benign epithelial odontogenic tumors.

BACKGROUND: Odontogenic tumors exhibited variable biologica behaviors. Metallothionein (MT) is correlated with the cellular homeostasis of essential metals, cellular differentiation, and proliferation. The core goals of this study are (i) to report and to compare MT expression among benign epithelial odontogenic tumors; (ii) to correlate MT with cellular proliferation index; and (iii) to evaluate the influence of the inflammatory infiltrate on MT expression. MATERIALS AND METHODS: Ten cases of solid ameloblastomas (SABs), 4 squamous odontogenic tumors (SOTs), 5 adenomatoid odontogenic tumors (AOTs), and 3 calcifying epithelial odontogenic tumors (CEOTs) were subjected to immunohistochemical to anti-MT, anti-Ki-67, and anti-PCNA. Statistical analysis was performed using BioEstat(®) 4.0. RESULTS: Metallothionein staining was found to be the highest in the SABs (93.1%), followed by SOTs (52.9%), AOTs (38.4%), and CEOTs (0%). MT staining exhibited statistically significant differences between the SABs and the SOTs (P = 0.0047) and the AOTs (P = 0.0022). A weak-to-strong positive correlation between IMT and IK or IP was observed in SABs and SOTs, whereas a strong negative correlation was observed in AOTs. No differences in IMT, IK, and IP were observed between inflammation groups A and B. CONCLUSIONS: The increased MT expression observed in the SABs might be correlated with clinical behavior (local invasiveness and high rate of recurrence). In the SABs and SOTs, MT plays a role in the stimulation of cellular proliferation. In contrast, MT can inhibit cellular proliferation in the AOT. The IMT, IK, and IP are not affected by inflammation.

Profile of usage of a reference diagnostic service on oral pathology: a 10-year evaluation.

BACKGROUND: Despite the professional and academic relevance of the Brazilian oral pathology diagnostic laboratories, no information about their usage profile is available in the English literature. The objective of the present study is to report data about the histopathological and immunohistochemical exams performed in a Brazilian regional reference laboratory of oral pathology, as well as its main users. METHODS: Information about all histopathological exams performed between 2002 and 2012 was retrieved from the files of the Oral and Maxillofacial Pathology Service of the School of Dentistry of Universidade Federal de Minas Gerais. Data collected included: 1) requestor of exam; 2) diagnosis classification; and 3) immunohistochemical tests. Descriptive statistical analyses were done. RESULTS: 13,522 histopathological exams were performed, mean 1,229/year. The Public Health System of the city of Belo Horizonte was the main requestor of exams (77.13%), followed by private professionals (19.26%), and other cities (2.03%). Most lesions were considered benign (12,599/ 93.17%), with 854 malignant lesions (6.32%). 469 immunohistochemical tests were performed; 324 (69.08%) were from benign diagnosis, and 145 (30.92%) from malignant diagnosis. The most used antibodies were against S100, vimentin, smooth muscle actin, actin muscle specific HHF-35, and pan-cytokeratin AE1/AE3. CONCLUSIONS: Public Health System is the major user of the diagnostic service on oral pathology in our institution. Most diagnoses were of benign lesions, although many malignant lesions were detected. Immunohistochemistry was particularly important in solving challenging cases.

Clinical and demographic overlaps among immunologically mediated oral diseases: a challenge for clinicians.

This study sought to assess and compare retrospective demographic and clinical data of oral lesions of lichen planus, pemphigus vulgaris, and mucous membrane pemphigoid from the records of the Department of Oral Pathology and Surgery, School of Dentistry, Universidade Federal de Minas Gerais, Brazil, covering a period of 55 years. Out of 25,435 specimens, these immunologically-mediated diseases accounted for 301 (1.18%) cases, of which 250 (0.98%) were lichen planus, 27 (0.11%) were pemphigus vulgaris, and 24 (0.09%) were mucous membrane pemphigoid. Lichen planus presented mainly as white asymptomatic plaques on buccal mucosa. Pemphigus vulgaris was usually characterized by multiple symptomatic erithematous ulcers on the buccal mucosa. Painful ulcers and/or blisters on the gingiva were the most common presentation for mucous membrane pemphigoid. Desquamative gingivitis was noted for all 3 diseases, but mainly for mucous membrane pemphigoid. Overall, lesions were more frequent in white women >50 years. Oral manifestations of immunologically-mediated diseases are relatively rare, and the correct diagnosis can be a challenge for dentists as the lesions often share similar clinical and demographic features.

Evaluation of GLUT-1 in the granular cell tumour and congenital granular cell epulis.

BACKGROUND: The glucose transporter type 1 (GLUT-1) protein is a useful marker for perineurial cells. Because of the possible neuroectodermal histogenesis of the granular cell tumour and congenital granular cell epulis, the aim of this study was to assess the immunoexpression of GLUT-1 protein in granular cell tumour and congenital granular cell epulis to aid in clarifying their histogenesis. METHODS: The protocol of this study was approved by the Committee of Bioethics in Research at Universidade Federal Minas Gerais. Six cases of granular cell tumour and three cases of congenital granular cell epulis were submitted to immunohistochemistry for GLUT-1 and S-100 using the streptavidin-biotin standard protocol. RESULTS: Five cases of granular cell tumour were located on the tongue and one case on the upper lip. All cases of congenital granular cell epulis were observed in the alveolar ridge of newborns. All lesions evaluated proved to be immunonegative for GLUT-1. S-100 was found to be positive in all granular cell tumours and negative in congenital granular cell epulis. CONCLUSIONS: Neither granular cell tumour nor congenital granular cell epulis is directly related to perineurial cells.

Correlation between salivary anti-HCV antibodies and HCV RNA in saliva and salivary glands of patients with chronic hepatitis C.

BACKGROUND: To investigate the correlation between anti-hepatitis C virus (HCV) antibodies in saliva and detection of HCV RNA in saliva and salivary glands of patients with chronic hepatitis C. METHODS: A total of 180 samples of saliva (131 non-stimulated and 49 stimulated) from 133 patients with chronic hepatitis C were tested by ELISA for presence of anti-HCV antibodies. Results were compared with the detection of HCV RNA in saliva and salivary glands samples. Pearson's chi-squared and Fisher's exact tests were performed for statistical analysis. RESULTS: Anti-HCV antibodies could be detected in 47/180 (26.1%) saliva samples. In 11/47 (23.5%) of these, HCV RNA was also detected. From the 133/180 (73.9%) saliva samples with undetectable anti-HCV antibodies, 49/133 (36.8%) were positive for HCV RNA at least in one saliva sample. From the 64 patients from whom salivary gland samples were available, 17/64 (26.6%) had detectable anti-HCV antibodies in saliva, from which 2/17 (11.8%) also had HCV RNA in the salivary gland. From the 47/64 (73.4%) cases negative for anti-HCV antibodies in saliva, 10/47 (21.3%) were positive for HCV RNA in salivary gland. CONCLUSIONS: Taken together, our results suggest that there is no correlation between the presence of anti-HCV antibodies in saliva and the detection of HCV RNA in saliva and salivary glands in patients with chronic hepatitis C. Nevertheless, as there was a statistically significant difference between detection of anti-HCV antibodies and HCV RNA in stimulated saliva, our study points toward the need for new research on mechanisms of HCV shedding in saliva.

Oral and oropharyngeal cancer: time from first symptoms to treatment initiation and associated factors.

The aim of this study was to evaluate the time elapsed from first symptoms to the treatment of oral and oropharyngeal cancer (OOC) and to identify variables associated with treatment delay. This is an observational study with retrospective and prospective data collection. Patients with a diagnosis of OOC seen at the Head and Neck Surgery outpatient clinic of a Brazilian public hospital were included and followed up to treatment initiation. Participants answered a questionnaire for the collection of socioeconomic, demographic, cultural, and clinical information, as well as information about the time elapsed from first symptoms to the first appointment with a head and neck surgeon. Time to treatment was classified into four intervals: 1- first symptoms to first medical appointment; 2- first medical appointment to specialized medical care; 3- specialized medical care to preparation for treatment; and 4- preparation for treatment to treatment initiation. Bivariate statistics were computed. Out of 100 participants, nine died before treatment. Mean time to treatment was 217 days. Highest mean time was observed for interval 2 (94 days), followed by interval 1 (63 days), interval 4 (39 days), and interval 3 (21 days). At interval 1, a longer time was associated with severe alcohol consumption, severe smoking, and family history of cancer. At interval 2, the delay was associated with appointment with a general practitioner, clinical diagnosis of disease other than cancer, and antibiotic prescription. At interval 4, delay in treatment was associated with surgical treatment. Patients with OOC experience delays from symptom onset to treatment initiation. The longest interval was associated with professional delay, followed by patient delay in help-seeking.

Antimicrobial photodynamic therapy for the treatment of oral mucositis-A comparative study.

OBJECTIVES: The aim was to evaluate the effectiveness of photobiomodulation and antimicrobial photodynamic therapy in the treatment of oral mucositis. BACKGROUND: Oral Mucositis is a frequent complication of oral cavity and oropharynx cancer. Considering the OM aggravation by microorganisms contamination, disinfection provide by antimicrobial photodynamic therapy could be an effective approach. MATERIAL AND METHODS: This comparative study included fourteen patients undergoing radiochemotherapy for oral cavity and oropharynx cancer treatment, who developed oral mucositis. CONTROL GROUP: photobiomodulation. Intervention group: photobiomodulation and antimicrobial photodynamic therapy. The lesion size, duration, pain, and identification of microorganisms were evaluated. RESULTS: The mean reduction in oral mucositis size in the intervention group was 0.70 cm² (±0.35) and 0.30 cm² (±1.10) for the control group. The mean duration of oral mucositis was 18.37 days (±12.12) for the intervention group and 23 days (±14.78) for the control group. The intervention group had a mean reduction of 3.40 points on the pain scale (±2.44), while the control group had 0.17 (±2.28). In the intervention group, the predominant isolated microbiota was featured as mixed culture (n = 4/ 50%), followed of Gram Positive (n = 3/ 37.50%), and Gram Negative (n = 1/ 12.55%). In the control group, mixed culture was also more frequent (n = 4 / 66%), followed by Gram Positive (n = 2 /34%). Gram Negative was not predominantly isolated in the control group. CONCLUSION: No statistical significance was found between PBM-T alone and PBM-T + PDT. However, the better outcomes reached by PBM-T + PDT group would suggest there could be a role for combined treatment in the management of OM lesions.

Clinicopathological Features of Metastasis to the Oral and Maxillofacial Region-Multicenter Study.

BACKGROUND: This study aimed to investigate the clinicopathological features of metastases in the oral and maxillofacial regions. METHODS: In this retrospective study, biopsy records were obtained from referral centers for oral and maxillofacial diagnosis in Brazil, Guatemala, Mexico, and South Africa. RESULTS: A total of 120 cases were evaluated. Of these, 53.78% affected female patients, with a mean age of 57.64 years. Intraosseous lesions were more frequent, particularly in the posterior region of the mandible (49.58%). Clinically, most cases presented with symptomatic swelling, with an average evolution time of 25 months. The clinical diagnostic hypothesis in most instances was that of a malignant lesion. Breast cancer was the most common primary tumor location in females, while lung origin was most common in males. In most cases, the primary cancer was an adenocarcinoma (44.73%). The follow-up period was available for 29 cases, and out of these, 20 had died due to the disease. CONCLUSION: Although this is a rare condition, clinicians should be aware that any oral lesions have the possibility of being metastatic, particularly in individuals with a previous history of cancer. The findings from this study could assist clinicians in prompt diagnosing these lesions and subsequent conducting oncologic assessments and treatment.

DNA damage-related proteins in smokers and non-smokers with oral cancer.

Tobacco smoking involves a high risk of human malignancies, including oral cancer, because it contains multiple carcinogens that cause genetic instability. Thus, a worse prognosis would be expected for cancer patients who are smokers. The aim of this study was to assess the DNA damage response through the expression of checkpoint kinase 2 (CHK2), H2A histone family member X (H2AX), and P53 among smokers and non-smokers with oral squamous cell carcinoma (OSCC). Associations between immunoexpression of proteins and clinicopathological data and histopathological grading were also analyzed. A total of 35 individuals (18 non-smokers and 17 smokers) with OSCC of the tongue and/or floor of the mouth were included. Immunohistochemistry for H2AX was conducted for the identification of double-strand breaks, CHK2, and P53 to evaluate the expression of this protein in cell cycle regulation. The sample consisted of 22 males and 13 females, with a mean age of 63.9±11.8 years. OSCC of non-smokers were well-differentiated tumors in 50% of the cases, and those of smokers were equally distributed into moderately differentiated and poorly differentiated tumors (35.3% each). Overall, 31 (88.6%) cases were CHK2-positive, 27 (77.1%) were H2AX-positive, and 23 (65.7%) were P53-positive, with no difference between smokers and non-smokers (p > 0.05). No association was found between proteins and clinicopathologic data (p > 0.05). Similarities in CHK2, H2AX, and P53 immunohistochemical staining patterns were observed between smokers and non-smokers, and immunoexpression was not associated with clinicopathological parameters. However, the findings indicated consistent expression of these proteins in OSCC.

Oral leukoplakias with different degrees of dysplasia: comparative study of hMLH1, p53, and AgNOR.

BACKGROUND: hMLH1 is one of the major proteins of the mammalian mismatch repair system. It has been suggested that the mismatch repair machinery could be linked to p53, a tumor suppressor protein. The AgNOR technique is used to assess cell proliferation. The aim was to compare the immunoexpression of hMLH1 and p53, and AgNOR number in oral leukoplakias with different degrees of dysplasia. METHODS: Sixty-two samples were evaluated by immunohistochemistry for hMLH1 and p53, and AgNOR technique, being 17 without dysplasia, 19 with mild dysplasia, 16 with moderate dysplasia, and 10 with severe dysplasia. RESULTS: hMLH1 immunoexpression showed decreasing indexes, while p53 and AgNOR showed increasing indexes from lesions with lower degrees of dysplasia to lesions with more severe dysplasia. An inverse correlation between hMLH1 and both p53 and AgNOR, and a direct correlation between p53 and AgNOR were observed. CONCLUSIONS: Alterations in the immunoexpression pattern of hMLH1 and p53 seemed to be early events in oral carcinogenesis. During acquisition of a more dysplastic phenotype, keratinocytes may show diminished capacity of DNA repair and tumor suppression, as well as higher cellular proliferation, and these pathways can be somehow interconnected.

hMLH1 immunoexpression is related to the degree of epithelial dysplasia in oral leukoplakia.

BACKGROUND: hMLH1 is a protein of the mammalian mismatch repair system responsible for genomic stability during repeated duplication. Relation between its altered expression linked to microsatellite instability has also been observed in oral leukoplakias (OL) and squamous cell carcinomas pointing to a possible role of hMLH1 in oral carcinogenesis. To our knowledge, this is the first study evaluating the immunoexpression of hMLH1 in OLs regarding their different degrees of epithelial dysplasia. METHODS: Sixty-two specimens of OL were classified in four groups: 17 without dysplasia, 19 with mild dysplasia, 16 with moderate dysplasia, and 10 with severe dysplasia. Immunohistochemistry for hMLH1 was performed, and percentage of positive cells was assessed. In the statistical analysis, P values <0.005 were considered significant. RESULTS: hMLH1 immunoexpression showed decreasing indexes from lesions with lower degrees of dysplasia to lesions with more severe dysplasia. Statistical difference was found mainly between suprabasal layers and total indexes. CONCLUSIONS: hMLH1 immunoexpression was inversely related to the OL degree of dysplasia. The total epithelial hMLH1 index seems to be of more clinical relevance than the evaluation stratified by layers. Our findings also suggest a role of such alterations in this pathway of DNA repair as an early event in oral carcinogenesis.

Metallothionein in the radicular, dentigerous, orthokeratinized odontogenic cysts and in keratocystic odontogenic tumor.

BACKGROUND: Metallothionein (MT) is a protein correlated with cellular differentiation and proliferation, as well as with the inhibition of apoptosis. The aims were to report and to compare the MT expression in odontogenic cysts and keratocystic odontogenic tumor (KOT); to correlate the MT with cellular proliferation; and to evaluate the influence of the inflammation in MT. METHODS: Nine cases of radicular cyst (RC), nine dentigerous cyst (DC), four orthokeratinized odontogenic cyst (OOC), and eight KOT were submitted to immunohistochemistry using anti-MT and anti-Ki-67. Indexes of MT (IMT) and Ki-67 (IK) were obtained. Lesions were grouped according to inflammation: mild-to-moderate (group A) and intense (group B). RESULTS: IMT proved to be highest in RC (91%), followed by DC (89%), KOT (78%), and OOC (63%). IMT was inversely correlated with IK in KOT, and OCC, but was positively correlated with RC and DC. No differences in IMT and in IK could be observed between groups A and B. CONCLUSIONS: The higher IMT found in RC and DC compared to OCC and KOT, as well as the differences between the last ones, is possibly correlated with their different histopathological features and clinical behavior. In RC and DC, MT may play a role in cellular proliferation. However, it seems that MT is either less or is not related to proliferation in OOC and in KOT. Moreover, inflammation does not seem to alter IMT and IK.