Aims: To analyse the expression of proteins involved in DNA double strand break detection and repair in the luminal and myoepithelial compartments of benign breast lesions and malignant breast tumours with myoepithelial differentiation. Methods: Expression of the ataxia telangiectasia (ATM) and p53 proteins was immunohistochemically evaluated in 18 benign and malignant myoepithelial tumours of the breast. Fifteen benign breast lesions with prominent myoepithelial compartment were also evaluated for these proteins, in addition to those in the MRE11-Rad50-NBS1 (MRN) complex, and the expression profiles were compared with those seen in eight independent non-cancer (normal breast) samples and in the surrounding normal tissues of the benign and malignant tumours examined. Results: ATM expression was higher in the myoepithelial compartment of three of 15 benign breast lesions and lower in the luminal compartment of eight of these lesions compared with that found in the corresponding normal tissue compartments. Malignant myoepithelial tumours overexpressed ATM in one of 18 cases. p53 was consistently negative in benign lesions and was overexpressed in eight of 18 malignant tumours. In benign breast lesions, expression of the MRN complex was significantly more reduced in myoepithelial cells (up to 73%) than in luminal cells (up to 40%) (p = 0.0005). Conclusions: Malignant myoepithelial tumours rarely overexpress ATM but are frequently positive for p53. In benign breast lesions, expression of the MRN complex was more frequently reduced in the myoepithelial than in the luminal epithelial compartment, suggesting different DNA repair capabilities in these two cell types.

O objetivo do estudo foi avaliar a prevalência de marcadores sorológicos da infecção pelo vírus da hepatite B (HBV) em pacientes atendidos em um laboratório particular da cidade de Parnaíba, Piauí, no período de janeiro a dezembro de 2018. Trata-se de um estudo epidemiológico transversal, retrospectivo. Um total de 214 pacientes adultos foram incluídos. A presença do antígeno HBsAg foi detectada em quatro (1,9%) pacientes enquanto que o marcador de imunidade anti-HBs foi detectado em 92 (43%) pacientes. A presença do anti-HBc IgG foi detectada em 13 (6,1%) casos. Em seis (2,8%) pacientes foi possível detectar a presença concomitante do Anti-HBs e anti-HBc total. A idade dos pacientes variou de 2 a 86 anos (Média: 36,88 anos; DP: ± 14,77 anos). A presença do HBsAg e do anti-HBc IgG que são marcadores da infecção pelo HBV foi detectada em maior frequência em pacientes com a faixa etária entre 46 a 59 anos. Por outro lado, a ausência desses marcadores foi observada em pacientes mais jovens. O presente estudo demonstrou uma prevalência considerada baixa para o HBsAg e anti-HBc, sugerindo que a população avaliada apresenta uma menor endemicidade da infecção pelo HBV.