Evaluación de las características genotípicas y fenotípicas como predictores de malignidad en citologías orales

ZARATE AM; BREZZO MM; SECCHI D; LAZOS J; BARRA JL ; BRUNOTTO M

Florianopolis

Congreso; 55ª Reunión Anual de la Región Brasilera de la Sociedad Internacional de Biometría y 15ª Reunión Anual de la Región Argentina de la Sociedad Internacional de Biometría; 2010

Nowadays, complex diseases have begun to be the focus of study to health sciences.Researchers seek to improve the accuracy of diagnosis of the pathologies since in similarcellular and symptoms conditions dissimilar phenotypes can be obtained.[1]. In complexdiseases, oral cancer is a one of them that involves environmental factors and several genesthat regulate proliferation and cell death. Epidemiology has described some environmentalrisk factors for oral cancer such as the tobacco and alcohol as well as genetic epidemiologyand experimental studies have identified some genes for tumor transformation of cells likethe TP53 gene [2]. The assessment of the value of diagnostic indicators such as symptomsand genetic testing allows to estimate the sensitivity and specificity of these indicators todetermine the presence / absence of a pathology. But these estimates are only accurate ifbased on reliable data, otherwise the final estimate measured with error. Models such aslatent class analysis allows an estimate of the characteristics of indicators even when adiagnosis is not available [3]. In latent class models both observed and latent variables arecategorical. The categories of the latent variable c = 1, 2 classifying subjects into oral cancerand disorders oral potentially malignant. The conditional response probability for variable i,given latent class membership c, is given by , where are free parameters.The probabilitythat subject j belongs to latent class c is also a free parameter, denoted . We studiedcharacteristics of age, sex, clinical phenotype (presence of cellular atypia and lesions of oralsoft tissues ), genotype (mutations in exons 5-8 of the TP53 gene), smoking and alcoholconsumption of patients with oral cancer pathology and oral potentially malignant disorders.The outcome probabilities showed that patients who were aged over 45 years, with smokingand alcohol consumption and family history of cancer had a high probability of beingclassified in class oral cancer.