Reactivity of p53 protein in canine transmissible venereal tumor

Abstract

The expression of p53 protein was evaluated in canine transmissible venereal tumor (CTVT), as following: natural occurrence (n=8); resistant to chemotherapy (n=4); and allogeneic transplanted in progression (n=8), stable (n=8), and regression (n=8)stages. The collected specimens were submitted to GM1 immunohistochemical reaction. Results showed a mean percentage of immunomarked cells around 18.6% in CTVT of natural occurrence, 23.8% in CTVT resistant to chemotherapy, 22.9% in allogeneic transplanted CTVT in both progression and stable stages, and 35.8% in transplanted CTVT in regression stage. The results suggest that there is a functional abnormality in p53 gene and its products in the studied tumors; although, it is not possible to correlate the percentage of cells marked by p53 and a prognosis.Keywords: immunohistochemistry, p53, oncology, transmissible venereal tumor 18,6% no TVT de ocorrência natural, de 23,8% no TVT refratário, 22,9% imunoistoquímica, p53, oncologia, tumor venéreo transmissível RESUMO A expressão da proteína p53 foi avaliada em espécimes de tumor venéreo transmissível canino (TVT) de ocorrência natural (n=8); resistente à quimioterapia (n=4) e transplantado em cão nas fases de progressão tumoral (n=8), de latência (n=8) e de regressão (n=8). Os espécimes foram submetidos à reação de imunoistoquímica. Os resultados mostraram porcentagem média de células imunomarcadas de

Pathological and immunohistochemical studies on rare cases of primary extragenital transmissible venereal tumours in the mammary gland

“…This might be the reason for the weak immunoreactivity of both the clones of p53 used in the present study. Moro et al (2010) have similarly reported weak immunoreactivity to p53 in natural cases of TVT in dogs. Another reason for the low immunoreactivity of p53 in the present study may be that some antihuman p53 antibodies do not react adequately with canine tissues.…”

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

“…In that context, although the molecular analysis of P53 was not applied in this research, it is believed that possible gene mutations are the cause of the changes in the conformation of the protein, leading to increased half-life, occasional function loss and accumulation in cells, as described by Calazans et al (2010) and Lima et al (2012a). In the same way, Santos et al (2008) and Moro et al (2010), while investigating the functional impairment of the p53 protein by immunohistochemistry, suggested that the immunolabeling pattern found indicates functional abnormality in p53 and in the protein formed from the transcription of the abnormal gene, although they have not been able to correlate the percentage of labeled cells to the prognosis of TVT.…”

“…This fact supports the hypothesis of dysfunction of C-MYC and p53 proteins, with consequent maintenance of cell growth and progression of TVT. Despite the description of apoptosis on TVT (Moro et al, 2010), no information was found about the impairment of the apoptotic mechanism related to the dysfunction of the C-MYC protein. On the other hand, Santos et al (2008) studied the apoptosis in TVT by evaluating the integrity of p53 in experimentally transplanted tumors and found that, during tumor regression, the p53 expression was higher if compared to the progression phase.…”

“…Although the p53 expression is described in TVT cells, there are no reports about this relationship, as well as C-MYC proteins, with those inhibiting the cell cycle and dependent on kinases (Moro et al, 2010).…”

Immunohistochemical Detection of p53 Tumor Suppressor Protein in Round Cell Tumors of Dogs in Grenada, West Indies

“…More than 10 mutations in the P53 gene have been described in canine neoplasias (Oren, 1999;Setoguchi et al, 2001), including cases of TVT (Choi and Kim, 2002;Sánchez-Servín et al 2009;Stockmann et al 2011). Moro et al (2010) found more cells that expressed p53 protein in transplanted TVT in the regression phase compared with naturally occurring TVT. These findings suggested that there may be functional abnormalities in the p53 gene and its transcription in these tumors (Stockmann et al 2011).…”