Immunohistochemical Expression of Mdm2 and p53 in Canine Cutaneous Mast Cell Tumours

Abstract

The objective of this study was to evaluate by immunohistochemical means nuclear reactivity for Mdm2 and p53 proteins in 71 canine cutaneous mast cell tumours. Detectable reactivity for Mdm2 was observed in 17 of 23 grade I tumours, 19 of 27 grade II tumours, and 14 of 21 grade III tumours, the grading method used was that by Patnaik et al. [Vet. Pathol., vol. 21, 1984, p. 469]. Increased reactivity for Mdm2 was detected in grade III tumours compared with grade I tumours. In contrast to Mdm2, detectable reactivity for p53 was observed in 17 tumours. Of 39 cases with moderate or marked Mdm2, 34 showed mild or no detectable p53, although only five showed moderate or marked p53. The results suggest that Mdm2 overexpression plays a crucial role in canine mast cell tumorigenesis and is consistent with the histologic grade, and its expression may be induced without p53 overexpression.

Polymorphism of P53‐Ets/AP1 transactivation region of MDM2 oncogene and its immunohistochemical analysis in canine tumours

“…We also identified amplification of MDM2 protein in all tumours that exhibited mutation within the MDM2 promoter. The percentage of canine mammary tumours expressing MDM2 in this study had the same rate when compared with other canine malignant cancers reported previously . In accordance with our data, MDM2 amplification or overexpression has been reported in various canine cancers, including soft tissue sarcomas, osteosarcoma and mast cell tumours .…”

“…The percentage of canine mammary tumours expressing MDM2 in this study had the same rate when compared with other canine malignant cancers reported previously. 6,31 In accordance with our data, MDM2 amplification or overexpression has been reported in various canine cancers, including soft tissue sarcomas, osteosarcoma and mast cell tumours. 5,6,31 MDM2 overexpression is also reported to correlate with tumour invasiveness and poor survival in various human cancers.…”

“…6,31 In accordance with our data, MDM2 amplification or overexpression has been reported in various canine cancers, including soft tissue sarcomas, osteosarcoma and mast cell tumours. 5,6,31 MDM2 overexpression is also reported to correlate with tumour invasiveness and poor survival in various human cancers. 16,18 -20 With these backgrounds, we hypothesised that MDM2 promoter polymorphism might affect promoter activity and subsequently alter protein expression level in canine mammary tumours.…”

Inhibitory effect of naringenin via IL‐13 level regulation on thymic stromal lymphopoietin‐induced inflammatory reactions

“…8 TSLP induces proliferation of human mast cell line (HMC-1) and the up-regulations of TSLPR and IL-7Rα. 9 Murine double-minute 2 (MDM2) plays a central role in mast cell tumourigenesis and regulates the transcriptional function of p53 protein, 10 and interestingly, MDM2 is also overexpressed in AD lesions. 11 In mast cells, TSLP inhibits the expression of apoptosis-inducing factors by increasing the expression of MDM2.…”

Avaliação de macrófagos e eosinófilos associados ao tumor como fatores prognósticos em mastocitomas cutâneos caninos

“…A expressão da proteína p53 foi avaliada juntamente com a expressão da proteína MDM2 em MCTs cutâneos caninos, e mostrou-se superexpressa, nos MCT de grau III, com moderada à marcada reatividade nuclear, sugerindo que a expressão desta proteína correlaciona-se ao grau histológico da neoplasia e pode exercer um papel na carcinogênese do MCT canino. Uma correlação entre MDM2 e TP53 não foi identificada, sugerindo uma regulação independente do TP53(WU et al, 2006).…”