c-Jun, pc-Jun, and p27 are differently expressed in oral leukoplakias in smokers and never-smokers.

OBJECTIVE: Oral cancer may be preceded by potentially malignant lesions, and smoking is a risk factor. Oral leukoplakia (OL), which is the most common among these lesions, is defined by the World Health Organization as "a white plaque of questionable risk having excluded known diseases or disorders that carry no increased risk for cancer." Thus, OL is a clinical diagnosis used to designate oral white lesions, which are histologically represented by hyperkeratosis associated or not associated with epithelial dysplasia. It is known that c-Jun and pc-Jun have a role in cell proliferation and that p27 is decreased during carcinogenesis; thus, the aim of this study was to investigate whether these proteins are differently expressed in OL in smokers and never-smokers. STUDY DESIGN: Seventy-three cases diagnosed as OL were selected and divided into four groups according to the presence or absence of dysplasia and patients' smoking status (smokers: 39 cases, 24 dysplastic; never-smokers: 34 cases, 20 dysplastic). The immunoexpressions of c-Jun, pc-Jun, and p27 were evaluated. RESULTS: A significant correlation between smoking condition and the percentages of c-Jun (P = .0356) and pc-Jun (P = .0216) was found and was more intense in cases that underwent malignant transformation (6/47). CONCLUSIONS: Smoking habits may be linked to the expression of proteins directly associated with cell cycle progression.

Oral leukoplakia manifests differently in smokers and non-smokers

Oral leukoplakias (OL) are potentially malignant lesions that are typically white in color. Smoking is considered a risk factor for developing OL, and dysplastic lesions are more prone to malignant transformation. The aim of this study was to describe the clinical features observed in dysplastic and non-dysplastic OL in both smokers and non-smokers. A total of 315 cases of OL were retrieved and separated into either dysplastic or non-dysplastic lesions, and these cases were further categorized as originating in either smokers or non-smokers. Frequencies of the type of OL lesion, with respect to whether the patients smoked, were established. The results demonstrated that 131 cases of OL were dysplastic (74 smokers and 57 non-smokers), and 184 were non-dysplastic (96 smokers and 88 non-smokers). For OL cases in smokers for which information about alcohol consumption was also available (84 cases), the results revealed no significant difference in the amount of dysplastic and non-dysplastic lesions. Dysplastic lesions were more frequent in male smokers and in non-smoking females. The median age of smokers with cases of OL was significantly lower than in non-smokers; the lowest median ages were observed for female smokers with dysplastic OL. The most frequent anatomical sites of dysplastic lesions were the floor of the mouth in smokers and the tongue in non-smokers. Dysplastic lesions in smokers were significantly smaller than non-dysplastic lesions in non-smokers. Being a male smoker, being female, being younger, and having smaller lesions were associated with dysplastic features in OL. These clinical data may be important for predicting OL malignant transformation.

Oral leukoplakia manifests differently in smokers and non-smokers.

Oral leukoplakias (OL) are potentially malignant lesions that are typically white in color. Smoking is considered a risk factor for developing OL, and dysplastic lesions are more prone to malignant transformation. The aim of this study was to describe the clinical features observed in dysplastic and non-dysplastic OL in both smokers and non-smokers. A total of 315 cases of OL were retrieved and separated into either dysplastic or non-dysplastic lesions, and these cases were further categorized as originating in either smokers or non-smokers. Frequencies of the type of OL lesion, with respect to whether the patients smoked, were established. The results demonstrated that 131 cases of OL were dysplastic (74 smokers and 57 non-smokers), and 184 were non-dysplastic (96 smokers and 88 non-smokers). For OL cases in smokers for which information about alcohol consumption was also available (84 cases), the results revealed no significant difference in the amount of dysplastic and non-dysplastic lesions. Dysplastic lesions were more frequent in male smokers and in non-smoking females. The median age of smokers with cases of OL was significantly lower than in non-smokers; the lowest median ages were observed for female smokers with dysplastic OL. The most frequent anatomical sites of dysplastic lesions were the floor of the mouth in smokers and the tongue in non-smokers. Dysplastic lesions in smokers were significantly smaller than non-dysplastic lesions in non-smokers. Being a male smoker, being female, being younger, and having smaller lesions were associated with dysplastic features in OL. These clinical data may be important for predicting OL malignant transformation.

Expressão imunohistoquímica das proteínas c-Jun não fosforilada/fosforilada e p27 em leucoplasias de pacientes fumantes e não fumantes / Immunohistochemical expression of non-phosphorylated / phosphorylated c-Jun and p27 proteins in leukoplakias from smokers and nonsmokers

Em diversos casos, o câncer bucal é precedido por lesões pré-malignas, como por exemplo, a leucoplasia, sendo que o tabaco é um fator de risco. No entanto, apesar deste potencial negativo, há estudos limitados em fumantes e não fumantes sobre o desenvolvimento de displasia para carcinoma. Sabe-se que o principal componente do factor de transcrição AP-1, a proteína c-Jun e a sua forma fosforilada (p-c-Jun), participam do ciclo celular e que sua inibição compromete a proliferação celular. A proteína p27 tem sido demonstrada como inibidora de quinase, e sabe-se que tem sua expressão diminuída durante a carcinogênese. A expressão diminuída de p27 tem sido relacionada a um pior prognóstico em carcinoma epidermóide. O objetivo deste estudo foi verificar a expressão das proteínas c-Jun, p-c-Jun e p27, em lesões potencialmente malignas diagnosticadas clinicamente como leucoplasia de pacientes fumantes e não fumantes. Foram selecionados 73 casos diagnosticados clinicamente como leucoplasias, os quais foram divididos nos seguintes grupos: leucoplasia com e sem displasia epitelial, e entre fumantes e não fumantes (perfazendo 4 grupos). Cortes histológicos das lesões foram classificados segundo o sistema de graduação binário, e subsequentemente submetidos à técnica imunohistoquímica da estreptoavidina-biotina.

Avaliou-se também a associação da proliferação celular pela c-Jun, p-c-Jun e p27 com o tabagismo, presença e ausência de displasia, localização e gênero. O presente estudo verificou que ocorrência de displasia epitelial em baixo e alto risco não teve associação com o hábito de fumar do paciente (p= 0,5430). Avaliando apenas a imunorreatividade das proteínas c-Jun, p-c-Jun e p27 individualmente observouse que a expressão destas não teve associação com a condição fumante do paciente (p> 0,05). Porém, ao compararmos a imunomarcação de c-Jun e p-c-Jun entre si, no total da amostra (p=0,0448) e somente para displasia em fumantes (p=0,0165), nota-se significativamente menor expressão de p-c-Jun. Comparando c-Jun e p27 nas displasias em não fumantes, houve significativamente maior expressão de c-Jun e menor expressão de p27 (p=0,0079). A análise do Teste binomial de duas proporções revelou que as regiões de língua e assoalho bucal estavam associadas à ocorrência de lesões displásicas quando comparadas a lesões não displásicas (p<0,0001). Concluiu-se que não houve correlação entre fumo e grau de displasia. A expressão das proteínas c-Jun, p-c-Jun e p27 foi independente da condição fumante do paciente.

In Several cases, the oral cancer is preceded by-malignant lesions potentially, such as leukoplakia, and that tobacco is a risk factor. However, despite this negative potential, there are limited studies in smokers and nonsmokers on the development of dysplasia to carcinoma. It is known that the main component of the transcription factor AP-1, c-Jun protein and its phosphorylated form (pc-Jun), participate in cell cycle inhibition and their committed cell proliferation. The p27 protein has been shown to inhibit kinase, and it is known that their expression is decreased during carcinogenesis. The decreased expression of p27 has been linked to poor prognosis in squamous cell carcinoma. The aim of this study was to evaluate the expression of proteins c-Jun, pc-Jun and p27 in potentially malignant lesions from smokers and non-smokers, diagnosed clinically as leukoplakiaa in smokers and nonsmokers. We selected 73 cases diagnosed clinically as leukoplakia, which were divided into the following groups: leukoplakia with and without dysplasia, and between smokers and nonsmokers (totaling 4 groups). Histological lesions were classified according to the binary grading system, and subsequently subjected to immunohistochemistry technique streptavidin-biotin. We also evaluated the association of cell proliferation of c-Jun, pc-Jun and p27 with smoking, presence and absence of dysplasia, location and gender. This study found that the occurrence of epithelial dysplasia in low-and high-risk had no association with the patient's smoking habit (p = 0,5430).

When evaluating the immunoreactivity of the proteins c-Jun, p27 and pc-Jun alone it was observed that the expression of them was also independent of the condition of the patient smoking (p> 0,05). However, when comparing the immunostaining of c-Jun and pc-Jun together, for the total sample (p = 0,0448) and only for dysplasia in smokers (p = 0,0165), there was significantly lower expression of pc-Jun. Comparing p27 and c-Jun in dysplasias in nonsmokers, there was significantly higher expression of c-Jun and reduced expression of p27 (p = 0,0079). The analysis of two binomial proportions test revealed that the lesions in the tongue and floor of the mouth were more prone to be dysplastic (p <0.0001). It was concluded that there was no correlation between smoking and degree of dysplasia. The expression of c-Jun, p27 and pc-Jun proteins was independent of smoking habit of the patient. The anatomoclinical aspects combined with the expressions of c-Jun and p27 may assist the pathologist in directing the histopathological diagnosis.