Insertion of the LINE-1 element in the C-MYC gene and immunoreactivity of C-MYC, p53, p21 and p27 proteins in different morphological patterns of the canine TVT

ABSTRACT The canine transmissible venereal tumor (TVT) affects the external genitalia of dogs by the natural transplant of viable tumor cells. Thus, this research aimed to diagnose and characterize TVT morphological patterns, identify the insertion of the LINE-1 element in C-MYC gene, by means of the polymerase chain reaction (PCR), and evaluate the immunohistochemical expression of C-MYC, p53, p21 and p27 proteins. The relationship between C-MYC and p53 proteins and their interference on the expression of p21 and p27 were also studied. For that, 20 samples of naturally occurring TVT were used, subjected to cytopathological, histopathological and immunohistochemical analysis, and to molecular diagnosis of neoplasia. The increased tissue expression and the correlation among C-MYC, p53, p21 and p27 proteins indicate reduction and/or loss of their functionality in the TVT microenvironment, with consequent apoptotic suppression, maintenance of cell growth and progression of neoplasia. Keywords: dog, cell , cytology, immunohistochemistry RESUMO O tumor venéreo transmissível canino (TVT) afeta a genitália externa de cães pelo transplante natural de células tumorais viáveis. Assim, esta pesquisa teve como objetivo diagnosticar e caracterizar TVT em padrões morfológicos, identificar a inserção do elemento LINE-1 em gene C-MYC, por meio da reação em cadeia da polimerase (PCR), e avaliar a expressão imuno-histoquímica do C-MY