Identification of p53 gene alterations in canine mammary tumours using polymerase chain reaction and direct sequence analysis

Mammary tumours are mentioned as the most common tumours in female dogs and approximately half of them are detected malignant. p53 gene mutations are demonstrated to be the most common genetic alteration in canine mammary tumours. The present study was conducted to evaluate exon-1 of p53 gene mutations in tissue samples of canine mammary tumours by PCR and direct sequence analysis. After histopathological confirmation of the tissue sections by haematoxylin and eosin staining (10/26), deparaffinised samples were used for DNA extraction by silica gel method. Subsequently, p53 exon 1 was amplified through PCR assay using specific oligo nucleotide primers designed according to the canine DNA sequence available online. Microscopically, 10 out of 26 suspected tissue samples were recognised as malignant mammary gland tumours with various grades of malignancy. Surprisingly, one insertion of mutation was found in exon 1 of all examined samples corresponding to a sequence comprising 27 amino acids, between amino acids 30 to 57 in the p53 protein. Taken together, it seems that alteration of exon 1 p53 gene may lead to malignancy beha­viour, poor prognosis and short survival time in dogs with mammary carcinomas.

TP53 Mutation in Correlation to Immunohistochemical Expression of P53 Protein in Patients with Hepatocellular Carcinoma

BACKGROUND: Mutations causing p53 inactivation are among the most common genetic alterations in human malignant tumours including hepatocellular carcinoma. Detection of p53 gene mutations in patients with hepatocellular carcinoma (HCC) should provide relevant data for the patients from the Republic of Macedonia and should allow the survivals additional therapeutic option as is gene therapy.AIM: We aimed to detect p53 gene mutations in HCC tissue, and to correlate them with the immunoexpression of p53 protein and multiple clinicopathologic characteristics of a tumour.MATERIAL AND METHODS: We analysed thirty patients with HCC for multiple clinic-pathological characteristics. Tumour tissue samples were immunostained for p53 and detection of p53 gene mutations was performed by polymerase chain reaction followed by Sanger sequencing.RESULTS: Changes in p53 gene sequence were detected in four patients (13.33%), one of them a polymorphism and the other three were missense point mutations with p53 immunoexpression of 50%, 0%, 0% and 90%, respectively. All patients with p53 mutations had cirrhosis. Two of them had Hepatitis B infection, moderately differentiated tumour and T2 status. There was one case with a well-differentiated tumour and one with T4 status. All of them were with vascular invasion. The size of the tumours was in the range of 2.5 cm to 16 cm. All 3 mutations were located in exon 7.CONCLUSION: Mutations in p53 gene are not always associated with obviously altered immunoexpression of p53 protein. Detection of p53 gene mutations is necessary in each case because the new therapeutic modalities offer to apply gene therapy.