Contribution of public oral pathology services to the diagnosis of oral and oropharyngeal cancer in Brazil.

This study aimed to evaluate the contribution of oral and maxillofacial pathology laboratories (OMPLs) in Brazilian public universities to the diagnosis of lip, oral cavity, and oropharyngeal squamous cell carcinoma (SCC). A cross-sectional study was performed using biopsy records from a consortium of sixteen public OMPLs from all regions of Brazil (North, Northeast, Central-West, Southeast, and South). Clinical and demographic data of patients diagnosed with lip, oral cavity, and oropharyngeal SCC between 2010 and 2019 were collected from the patients' histopathological records. Of the 120,010 oral and maxillofacial biopsies (2010-2019), 6.9% (8,321 cases) were diagnosed as lip (0.8%, 951 cases), oral cavity (4.9%, 5,971 cases), and oropharyngeal (1.2%, 1,399 cases) SCCs. Most cases were from Brazil's Southeast (64.5%), where six of the OMPLs analyzed are located. The predominant profile of patients with lip and oral cavity SCC was Caucasian men, with a mean age over 60 years, low schooling level, and a previous history of heavy tobacco consumption. In the oropharyngeal group, the majority were non-Caucasian men, with a mean age under 60 years, had a low education level, and were former/current tobacco and alcohol users. According to data from the Brazilian National Cancer Institute, approximately 9.9% of the total lip, oral cavity, and oropharyngeal SCCs reported over the last decade in Brazil may have been diagnosed at the OMPLs included in the current study. Therefore, this data confirms the contribution of public OMPLs with respect to the important diagnostic support they provide to the oral healthcare services extended by the Brazilian Public Health System.

Contribution of public oral pathology services to the diagnosis of oral and oropharyngeal cancer in Brazil

Abstract This study aimed to evaluate the contribution of oral and maxillofacial pathology laboratories (OMPLs) in Brazilian public universities to the diagnosis of lip, oral cavity, and oropharyngeal squamous cell carcinoma (SCC). A cross-sectional study was performed using biopsy records from a consortium of sixteen public OMPLs from all regions of Brazil (North, Northeast, Central-West, Southeast, and South). Clinical and demographic data of patients diagnosed with lip, oral cavity, and oropharyngeal SCC between 2010 and 2019 were collected from the patients' histopathological records. Of the 120,010 oral and maxillofacial biopsies (2010-2019), 6.9% (8,321 cases) were diagnosed as lip (0.8%, 951 cases), oral cavity (4.9%, 5,971 cases), and oropharyngeal (1.2%, 1,399 cases) SCCs. Most cases were from Brazil's Southeast (64.5%), where six of the OMPLs analyzed are located. The predominant profile of patients with lip and oral cavity SCC was Caucasian men, with a mean age over 60 years, low schooling level, and a previous history of heavy tobacco consumption. In the oropharyngeal group, the majority were non-Caucasian men, with a mean age under 60 years, had a low education level, and were former/current tobacco and alcohol users. According to data from the Brazilian National Cancer Institute, approximately 9.9% of the total lip, oral cavity, and oropharyngeal SCCs reported over the last decade in Brazil may have been diagnosed at the OMPLs included in the current study. Therefore, this data confirms the contribution of public OMPLs with respect to the important diagnostic support they provide to the oral healthcare services extended by the Brazilian Public Health System.

Mesenchymal Stem Cell Marker Expression in Periapical Abscess.

INTRODUCTION: There is evidence that acute periapical lesions present a greater potential for cyst formation. Recently, it was found that these lesions have cells with characteristics of pluripotent stem cells, which may influence cyst development. However, a more complete phenotype investigation of stem cells in a specific sample of periapical abscesses is required. The aim of this study was to analyze the immunohistochemical expression of mesenchymal stem cell (MSC) markers in periapical abscesses and to evaluate differences in their expression in relation to acute and chronic periapical lesions. METHODS: Immunohistochemistry was used to access MSC marker expression (CD44, CD73, and CD105) in samples of periapical abscesses (n = 10), granulomas (n = 10), cysts (n = 10), and apical papillae (n = 10). Immunohistochemical expression was evaluated by a quantitative scoring system. The chi-square test was used to assess the association between MSC marker expression and the histopathological diagnosis at a 5% significance level. RESULTS: CD44 and CD73 immunostaining was observed in mesenchymal cells located in the outer portion of the abscess and periapical cyst specimens. CD105 immunoexpression was found predominantly in mesenchymal and vascular endothelial cells of the lesions studied. MSC marker expression was higher in the periapical abscesses, with a significant association between MSCs and the histopathological diagnosis of an abscess (P < .05). CONCLUSIONS: The periapical region is a rich source of MSCs. The greater presence of MSCs in periapical abscesses found in this study could hold an important clue into understanding the pathological pathway of periapical cyst formation.

Nuclear metallothionein in oral squamous cell carcinoma: clinicopathological parameters and patient survival.

The aim of this study was to identify the immunoexpression of methallothionein in oral squamous cell carcinoma as well as to address the correlation with clinical features, histological grade and patient survival. Samples were collected from 93 patients with tongue squamous cell carcinoma who presented for follow-up. Immunohistochemical expression of methallothionein in all groups was performed. The scoring system has previously been published by Tsurutani in 2005, which is based on intensity and distribution of staining. We used Kappa index to evaluate the degree of observers' agreement under metallothionein immunostaining and histological grade. Associations between methallothionein expression and clinical parameters (age, gender, smoking, tumor size, lymph node metastasis and disease stage) were examined for statistical significance using the chi-squared test. The overall survival rates were estimated by the Kaplan-Meier method and the relationship between protein expression and survival was compared using the log-rank test (p < 0.05). Our results showed no statistically significant association between methallothionein immunostaining and the selected clinicopathological variables. Immunohistochemistry results showed positive nuclear immunostaining for metallothionein in 62,37% (58/93) and negative for metallothionein 37,63% (35/93). The degree of examiners agreement by Kappa varied from substantial to perfect and both metallothionein immunostaining and histological grade were explored. The present study suggests that positive methallothionein expression found in tongue squamous cell carcinoma may not help to predict survival in the analyzed samples, as well as no relation between the protein and histological grade and clinical features was observed. In conclusion, the present study suggests that metallothionein is not associated with tongue squamous cell carcinoma clinicopathological characteristics and aggressiveness.

Nuclear metallothionein in oral squamous cell carcinoma: clinicopathological parameters and patient survival

Abstract The aim of this study was to identify the immunoexpression of methallothionein in oral squamous cell carcinoma as well as to address the correlation with clinical features, histological grade and patient survival. Samples were collected from 93 patients with tongue squamous cell carcinoma who presented for follow-up. Immunohistochemical expression of methallothionein in all groups was performed. The scoring system has previously been published by Tsurutani in 2005, which is based on intensity and distribution of staining. We used Kappa index to evaluate the degree of observers' agreement under metallothionein immunostaining and histological grade. Associations between methallothionein expression and clinical parameters (age, gender, smoking, tumor size, lymph node metastasis and disease stage) were examined for statistical significance using the chi-squared test. The overall survival rates were estimated by the Kaplan-Meier method and the relationship between protein expression and survival was compared using the log-rank test (p < 0.05). Our results showed no statistically significant association between methallothionein immunostaining and the selected clinicopathological variables. Immunohistochemistry results showed positive nuclear immunostaining for metallothionein in 62,37% (58/93) and negative for metallothionein 37,63% (35/93). The degree of examiners agreement by Kappa varied from substantial to perfect and both metallothionein immunostaining and histological grade were explored. The present study suggests that positive methallothionein expression found in tongue squamous cell carcinoma may not help to predict survival in the analyzed samples, as well as no relation between the protein and histological grade and clinical features was observed. In conclusion, the present study suggests that metallothionein is not associated with tongue squamous cell carcinoma clinicopathological characteristics and aggressiveness.

Lugol Chromoscopy in the Follow-up of Head and Neck Carcinoma.

INTRODUCTION: Lugol is helpful in identifying early second primary tumors (SPTs) during oroscopy and pharyngoscopy, but this technique has not been assessed during follow-up visits with these patients. AIM: The aim of this study is to describe the use of Lugol (a low-cost method) to diagnose SPTs in the oral cavity and oropharynx. METHODS: Patients treated for squamous cell carcinoma of the head and neck were randomly assigned to two groups. Group A was examined with routine oroscopy and pharyngoscopy without Lugol, and Group B was examined with routine oroscopy and pharyngoscopy without stain and with Lugol. A total of 211 patients were included during 4 years. RESULTS: Six oral and oropharynx carcinomas were detected in Group A. Eighteen oral and oropharynx carcinomas were detected in Group B, twelve of which were not seen without chromoscopy but were detected with Lugol. CONCLUSION: Lugol increases the detection of malignant lesions compared to routine examination alone.

Chondroblastic osteosarcoma mimicking periapical abscess.

CASE REPORT: The present report describes a case of chondroblastic osteosarcoma in the periapical region of teeth #29, #30, and #31 of an 18-year-old male. Clinical history showed self-reported discomfort in the right posterior gingiva for over a month. Physical examination showed a small expansion and redness of the right mandibular buccal and lingual cortical plates, but no signs of pain or inflammation were observed. All the teeth responded positively to pulp sensibility. Periapical and panoramic radiographs showed slight periapical radiolucency in the roots of teeth #29 and #30, clear periodontal ligament space widening, and evident loss of lamina dura. Incisional biopsy was performed, and based on microscopic findings the diagnosis of chondroblastic osteosarcoma was confirmed. CONCLUSIONS: Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in differential diagnosis of jaw lesions that resemble periapical abscess.

Chondroblastic osteosarcoma mimicking periapical abscess

Abstract Lesions of non-endodontic origin may mimic periapical abscess. Osteosarcoma is a rare malignant lesion. Case report The present report describes a case of chondroblastic osteosarcoma in the periapical region of teeth #29, #30, and #31 of an 18-year-old male. Clinical history showed self-reported discomfort in the right posterior gingiva for over a month. Physical examination showed a small expansion and redness of the right mandibular buccal and lingual cortical plates, but no signs of pain or inflammation were observed. All the teeth responded positively to pulp sensibility. Periapical and panoramic radiographs showed slight periapical radiolucency in the roots of teeth #29 and #30, clear periodontal ligament space widening, and evident loss of lamina dura. Incisional biopsy was performed, and based on microscopic findings the diagnosis of chondroblastic osteosarcoma was confirmed. Conclusions Non-endodontic diseases associated with tooth root apex, such as chondroblastic osteosarcoma, should be included in differential diagnosis of jaw lesions that resemble periapical abscess.

Hiperplasia Endotelial Papilífera Intravascular Oral: relato de dois casos / Oral intravascular papillary endothelial hyperplasia: two cases report

A hiperplasia endotelial papilífera intravascular (HEPI) é uma lesão vascular não neoplásica, benigna e rara, especialmente em cavidade bucal. O presente artigo relata dois casos com diferentes apresentações clínicas de HEPI, envolvendo o lábio inferior. O primeiro caso se refere a um paciente que apresentava nódulo único submucoso, endurecido, arroxeado e assintomático em mucosa labial inferior. E o segundo se reporta a uma paciente que apresentava aumento de volume assintomático em lábio inferior com a mucosa entumecida e arroxeada desde o fundo de sulco. O exame histológico revelou vasos dilatados com proliferação de células endoteliais arredondadas, associadas a estruturas papilares, de tecido conjuntivo projetadas para o lúmen vascular, associadas a um trombo organizado, no primeiro caso, e a um hemangioma, no segundo. A ausência de células inflamatórias, atipia e necrose celular excluíram outras lesões vasculares, sendo o diagnóstico final de HEPI. O prognóstico da HEPI é excelente, uma vez que recidivas são raramente relatadas. A HEPI pode ser incluída no diagnóstico diferencial clínico de lesões labiais únicas, arroxeadas e endurecidas. E por caracterizarse histologicamente por uma proliferação de células endoteliais, é importante estabelecer o diagnóstico diferencial com o angiossarcoma, uma lesão de tratamento mais agressivo e pior prognóstico... (AU)

Intravascular papillary endothelial hyperplasia (IPEH) is a nonneoplastic vascular benign and rare lesion, especially in oral cavity. This article reports two cases of IPEH, with different clinical presentation, involving the inferior lip. The first case refers to a patient presenting a single submucosal indurated purplish and asymptomatic nodule in the lower labial mucosa. And the second, to a patient presenting an asymptomatic increase in the lower lip associated with a swelling and purplish oral mucosa. Histological examination showed dilated vessels with rounded endothelial cells proliferation associated with papillary structures of connective tissue projected to vascular lumen, associated with an organized thrombus in first case and a hemangioma in the second. The absence of inflammatory cells, cytologic atypia and necrosis excluded other vascular lesions, being the final diagnosis of IPEH. The prognosis of IPEH is excellent since recurrences are rarely reported. Isolated purplish and indurated labial lesions can include the IPEH as a possible clinical hypothesis. And, since is histologically characterized by a proliferation of endothelial cells, is crucial the establishment of the histological differential diagnosis with angiosarcoma, which requires a more aggressive treatment and has worse prognosis... (AU)

Stem Cell Marker Expression in Persistent Apical Periodontitis.

INTRODUCTION: This study evaluated the expression of CD90 (mesenchymal stem cell) and Sox2 (progenitor stem cell) markers in persistent apical periodontitis (PAP) (n = 16) and primary periapical lesions (PPLs) (n = 10). METHODS: All samples were classified histologically according to the intensity of inflammatory cell infiltrate in the periapical lesion. Immunohistochemistry was used to detect CD90 and Sox2 in PAP and PPLs. The Spearman correlation coefficient and the Mann-Whitney U test were used to analyze data at the 5% significance level. RESULTS: CD90 expression was found in mesenchymal cells and vascular endothelial cells of 68.5% of all cases of PAP. There was no correlation between CD90 expression and histopathological diagnosis (P = .053) or inflammatory cell infiltrate intensity (P = .112). CD90 staining was predominantly found in the vascular endothelial cells of 30% (n = 3) of PPLs. CD90 expression was significantly higher in PAP than in PPLs (Mann-Whitney U test, P < .05). Sox2 expression was found in all cases of PAP. Eventually, all mesenchymal and chronic inflammatory cells exhibited Sox2 expression. There was no correlation between Sox2 expression and histopathological diagnoses (P = .749), inflammatory cell infiltrate intensity (P = .510), or acute or chronic inflammatory cell infiltrate (P = .256). Sox2 expression was found in 100% of PPLs. There was no difference in Sox2 expression between PAP and PPLs (P = .477). CONCLUSIONS: Mesenchymal stem cells may contribute to the immunosuppressive environment in PAP. Additionally, distinct stem cell sources may be associated with the chronic nature of PAP as well as with the development of PPLs.

Neuroblastoma-like schwannoma of the lower labial mucosa: a rare morphologic variant of peripheral nerve sheath tumor.

Neuroblastoma-like schwannoma is a rare variant of benign nerve sheath neoplasia, which is histologically characterized by small round neoplastic Schwann cells radially arranged around collagenous cores with a configuration of rosette-like structures. We report the first documented case of neuroblastoma-like schwannoma of the oral cavity in a 26-year-old male patient who presented with swelling in the lower labial mucosa.

An unusual case of four simultaneous eruption cysts in an infant.

Eruption cyst is a benign lesion with favorable prognosis that may occur during the primary or permanent dental eruption. The purpose of this paper is to report the case of an infant who presented with multiple eruption cysts (ECs), describe their clinical and histological features, and discuss the treatment performed. The first ECs occurred around the primary mandibular central incisors when the patient was seven months old, which ruptured spontaneously. Ten months later, the patient presented with simultaneous eruption cysts around the primary mandibular and maxillary first molars, making the child very uncomfortable. Radiographically, all the involved molars had two thirds root formation. Two cysts, both on the right side, were surgically removed, and the other two ruptured spontaneously.

E-cadherin downregulation and Twist overexpression since early stages of oral carcinogenesis.

There is some evidence of Twist participation in oral carcinogenesis; however, little is known about its interaction with E-cadherin in oral squamous cell carcinoma (OSCC) development. This experimental study included an immunohistochemical analysis of Twist and E-cadherin proteins in paraffin-embedded specimens of oral leukoplakia (OL), OSCC, and normal oral mucosa. In addition, it was also performed a Western blot and double-immunofluorescence analysis of Twist and E-cadherin expression in OSCC cell lines. Significant differences in Twist and E-cadherin immunoexpression were observed between normal oral mucosa and OL, with an inverse relation since the earliest stages of oral dysplasia (r = -0,512; P < 0.001). Western blot and double-immunofluorescence analysis showed differences in Twist and E-cadherin expression among human oral keratinocytes and OSCC cell lines suggesting that downregulation of E-cadherin occurs in a dependent manner of Twist in OSCC. Our results showed a possible value of Twist and E-cadherin in the prediction of risk of oral epithelium malignant transformation.

Burkitt's lymphoma of the jaws in the Amazon region of Brazil.

OBJECTIVE: To describe the clinicopathologic and immunohistochemical features of Burkitt's lymphoma of the jaws in 7 patients of Northern Brazil. STUDY DESIGN: Clinical data concerning gender, age, affected site, clinical presentation, symptomatology and follow-up were collected from the clinical files. Histopathology was complemented with a broad immunohistochemical panel and in situ hybridization for Epstein-Barr virus (EBV). RESULTS: Most of the patients were infants and 5 out of 7 were males. The mandible was affected in 5 cases and all patients also presented abdominal involvement. All cases were positive for CD45, CD20, CD79a, CD10, Bcl-6 and EBV. Ki-67 proliferative index was approximately 100%. Six patients were treated with R-CHOP (Rituximab + Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone) chemotherapy, and 2 of these died of the disease. One young adult patient refused treatment and died 3 months after initial diagnosis. CONCLUSION: Burkitt's lymphoma of the jaws diagnosed in the Amazon region of Brazil present similar clinicopathologic features to those described in endemic areas of Africa, including EBV positivity.

Oestrogens and androgen receptors in oral squamous cell carcinoma.

OBJECTIVE: To investigate the gender-related expressions of androgen (AR), estrogen alpha (ERα) and beta (ERß) receptors and aromatase enzyme in oral squamous cell carcinomas (OSCC). MATERIALS AND METHODS: A total of 60 cases of OSCC (30 from males and 30 from females) were retrieved and submitted to immunohistochemistry. Also, steroid expression was studied in two OSCC cell lines using Western blotting and immunofluorescence. RESULTS: Immunohistochemistry demonstrated that ERß was expressed in almost 40% of the cases and AR in 26%. Aromatase enzyme and ERα were less commonly expressed. Only AR presented statistically significant differences between genders. Western blotting and immunofluorescence analysis demonstrated that ERß was abundantly expressed in the nuclei of both cell lines and aromatase enzyme presented a cytoplasmic expression. CONCLUSION: The detection of steroid hormones, especially ERß, can indicate a role of these proteins in the process of carcinogenesis of some OSCC. Further studies of the mechanisms involved may provide important biological information regarding therapeutic approaches.

Clinical and Histological Features of Multifocal Canalicular Adenomas of the Upper Lip

Canalicular adenoma (CA) is an uncommon benign salivary gland tumor that mostly occurs in the upper lip. Despite its benign nature, some patients may present multiple nodules and also microscopic growth that can be multifocal with foci of tumor within the adjacent gland. Microscopically, CA can be mistaken for a polymorphous low-grade adenocarcinoma (PLGA) or basal cell adenoma (BCA), and immunohistochemistry can be helpful in differentiating them. Two cases of canalicular adenoma showing tumor foci within the adjacent gland are described. Both cases occurred in the upper lip of white females aged 72 and 79 years. In addition to the histological multifocal aspect, one of the patients presented bi-lateral nodules. Histological examination of both lesions revealed interconnecting and branching canal-like structures composed by uniform columnar and sometimes cuboidal cells, partially encapsulated. Immunohistochemical analysis showed intense expression of cytokeratins (CK) 7, a weak reaction to CK14 and a negative reaction to vimentin. Upon the diagnosis of CA the lesions were excised. In conclusion, it is important to properly diagnose CA and differentiate its multifocal aspect from a malignant behavior.

O adenoma canalicular (AC) é uma rara neoplasia benigna de glândula salivar que ocorre com maior frequência em lábio superior. Apesar de sua natureza benigna, alguns pacientes podem apresentar múltiplos nódulos, além de apresentar microscopicamente um crescimento multifocal com focos de neoplasia na glândula adjacente. Microscopicamente, AC pode ser confundido com adenocarcinoma polimorfo de baixo grau ou adenoma de células basais, sendo a imunohistoquímica útil na diferenciação entre eles. Dois casos de AC com focos de neoplasia dentro da glândula são descritos. Ambos os casos ocorreram em lábio superior de dois indivíduos do sexo feminino com 72 e 79 anos de idade. Além do aspecto histológico multifocal, um dos pacientes apresentou nódulos bilaterais. A análise histológica dos dois casos revelou estruturas canaliculares interligadas, compostas por células colunares uniformes e cuboidais, parcialmente encapsuladas. A análise imunohistoquímica mostrou intensa marcação de citoqueratina (CK) 7, uma fraca expressão para CK14, e reação negativa para vmentina. Após o diagnóstico as lesões foram excisionadas. Conclusão: É importante o correto diagnóstico do AC e a diferenciação do aspecto multifocal de um comportamento maligno.

Effects of celecoxib treatment over the AKT pathway in head and neck squamous cell carcinoma.

BACKGROUND: Celecoxib, a non-steroidal anti-inflammatory drug that selectively inhibits cyclooxygenase-2 (COX-2), has shown an important anticarcinogenic effect for the treatment of squamous cell carcinoma. The use of COX-2 inhibitors has effectively inhibited the growth of Head and Neck Squamous Cell Carcinoma (HNSCC) cell lines, while a recent phase 1 trial demonstrated good response rate of cancer cells to this drug with minimal toxicity. Possible targets of celecoxib include proteins involved in cell proliferation and apoptosis control. Additionally, celecoxib antitumoral activity has been linked with a COX-2-independent event. METHODS: To better understand which cellular mechanisms are targeted by celecoxib, its effects upon the Akt signaling pathway using two different HNSCC cell lines were analyzed through cell viability assay, immunofluorescence, and Western blotting. RESULTS: The results showed decreased levels of Cyclin D1 and pAkt protein expression in vitro. The number of viable cells was also diminished after celecoxib treatment. CONCLUSION: As Akt pathway seems to be a valuable target for the HNSCC therapy, the results presented herein confirm that celecoxib can be considered as an alternative adjuvant drug for HNSCC treatment.

Câncer de boca baseado em evidências científicas / Oral cancer based on scientific evidences

Apesar dos inúmeros avanços no conhecimento científico do câncer de boca até o momento, muito ainda há para ser corretamente descoberto e compreendido. Convicções do passado foram substituídas por novas evidências científicas. O câncer de boca acomete cerca de 275.000 pessoas no mundo anualmente sendo mais de 14.100 casos no Brasil, em 90% dos casos é diagnosticado como carcinoma epidermoide. A taxa de mortalidade permanece praticamente a mesma de décadas passadas. Suas características clínicas são bastante conhecidas, mas apesar disso o número de pacientes diagnosticados tardiamente permanece alto. A biologia celular avançou muito, porém ainda carece de um marcador eficiente. A biópsia permanece como o padrão ouro do diagnóstico, apesar das pesquisas realizadas com outras técnicas. O tratamento odontológico de pacientes portadores de neoplasias malignas será cada vez mais comum nos consultórios e o Cirurgião-Dentista deverá estar preparado para diagnosticar e lidar com essas situações

Although the advances in the oral cancer knowledge, several issues have to be addressed for a better understood of this disease. Convictions of the past have been replaced by new scientific evidences. Oral cancer affects annually more than 275.000 people worldwide and more than 14.100 cases in Brazil, 90% of these are squamous cell carcinoma; the mortality rate remains the same for many decades. Their clinical characteristics are well known, but despite this, the number of patients with late diagnosis remains high. Cell biology had a great advance in the last years and a precise marker is still a dream. Biopsy remains the gold standard for diagnosis of oral cancer in spite of studies with other techniques. The dental treatment of oncologic patients will be more common and the dentist should be prepared to diagnose and manage these patients

TWIST and p-Akt immunoexpression in normal oral epithelium, oral dysplasia and in oral squamous cell carcinoma.

OBJECTIVES: The aim of this study was to evaluate the immunoexpression of TWIST and p-Akt proteins in oral leukoplakia (OL) and oral squamous cell carcinoma (OSCC), correlating their expressions with the histological features of the lesions. STUDY DESIGN: Immunohistochemical studies were carried out on 10 normal oral epithelium, 30 OL and 20 OSCC formalin-fixed, paraffin-embedded tissue samples. Immunoperoxidase reactions for TWIST and p-Akt proteins were applied on the specimens and the positivity of the reactions was calculated for 1000 epithelial cells. RESULTS: Kruskal-Wallis and Dunn's post tests revealed a significant difference in TWIST and p- Akt immunoexpression among normal oral mucosa, OL and OSCC. In addition, a significant positive correlation was found between TWIST and p-Akt expressions according to the Pearson's correlation test. CONCLUSIONS: The results obtained in the current study suggest that TWIST and p-Akt may participate of the multi-step process of oral carcinogenesis since its early stages.

Avaliação da expressão de microRNAs em linhagens celulares de carcinoma epidermoide de cabeça e pescoço e em cultura primária de queratinócitos orais / Evaluation of microRNA expression in head and neck squamous cell carcinoma cell lines and in primary culture of oral keratinocytes

Objective: Functional in vitro studies are fundamental to understand the role of microRNAs, small non coding RNA molecules that function as post-transcriptional regulators, in cancer. The objective of this study was to determine the applicability of head and neck squamous cell carcinoma cell lines and human oral keratinocytes as models for functional studies on microRNAs previously identified as deregulated in head and neck squamous cell carcinomas. Methods: The expression level of four microRNAs was assessed in cell lines and in primary cultures of oral keratinocytes using specific real-time polymerase chain reactions. The identity of oral squamous cell carcinoma cell lines was confirmed by means of STR (short tandem repeats) profiling. The possible impact of feeder-layer gene expression in global microRNA expression results from keratinocyte primary culture was also evaluated. Results: Significant differences in microRNA gene expression were observed among squamous cell carcinoma cell lines, particularly among cells lines from distinct subsites, as well as between primary culture of human keratinocytes and immortalized keratinocyte cell lines. Conclusions: Primary cultures of human keratinocytes and diverse tumor cell lines are relatively easy to obtain. However, each cell model possesses a characteristic phenotype; whereas one may be useful for a specific study, it may be inappropriate for another. Therefore, it is imperative that suitable cell lines are cautiously selected for functional studies in cancer.

Objetivo: Estudos funcionais in vitro são essenciais para a compreensão do papel de microRNAs, pequenas moléculas de RNA que desempenham papel importante na regulação gênica, no câncer. Neste estudo, analisamos a viabilidade de linhagens celulares derivadas de carcinoma epidermoide de cabeça e pescoço, queratinócitos orais provenientes de culturas primárias e queratinócitos imortalizados, como modelos para estudos funcionais de microRNAs previamente identificados como desregulados nesse tipo de carcinoma. Métodos: Avaliamos a expressão de quatro microRNAs em linhagens celulares e em cultura primária de queratinócitos orais por meio de reações em cadeia da polimerase em tempo real específica. As linhagens celulares de carcinoma epidermoide de boca foram previamente caracterizadas quanto ao seu perfil de sequências de DNA do tipo STR (do inglês short tandem repeats ou repetições curtas em sequência) com o objetivo de confirmar a identidade da linhagem. Avaliamos ainda a possível influência da expressão gênica detectada na camada de sustentação usada no cultivo de queratinócitos no resultado global obtido. Resultados: Nossos resultados apontam diferenças significativas na expressão dos microRNAs entre linhagens celulares passíveis de serem utilizadas como modelos para estudos funcionais em carcinoma epidermoide de cabeça e pescoço. Ressaltam-se diferenças entre linhagens de carcinoma de língua e de faringe, bem como diferenças expressivas entre a linhagem de queratinócitos orais imortalizados e queratinócitos orais normais provenientes de culturas primárias. Conclusão: Culturas primárias de queratinócitos orais bem como linhagens tumorais são obtidas de forma relativamente simples. Entretanto, cada modelo celular possui características particulares que os tornam mais ou menos adequados para um determinado estudo. Conclui-se que a seleção cuidadosa das linhagens é fundamental para estudos funcionais sobre câncer.