The canine transmissible venereal tumor (CTVT) is found mainly in dogs' sexual organs. Currently, it is widely accepted that all samples of CTVT show similar histopathological characteristics and share common genetic alterations. Despite the common genetic origin of CTVT, mutations in the P53 gene have been reported. In this study, we proposed that tumor samples can be genetically grouped using this gene. The presence of different subgroups of CTVT was determined in Mexican dogs using the TP53 gene sequence in CTVT samples. Four new polymorphisms were found and therefore, the CTVT samples were classified in five subgroups.
Animals ; Base Sequence ; Dog Diseases/*genetics ; Dogs ; Gene Expression Regulation, Neoplastic/physiology ; Molecular Sequence Data ; Mutation ; *Polymorphism, Genetic ; Tumor Suppressor Protein p53/*genetics ; Venereal Tumors, Veterinary/*genetics

Canine transmissible venereal tumor (CTVT) is a tumor that commonly occurs in genital and extragenital sites of both genders. Long interspersed nuclear elements (LINE-1) retrotransposon has a pivotal role in allogenic transfection among uncontrolled dog populations. This study aimed to perform pathomorphological, immunohistochemical, and in situ polymerase chain reaction (PCR) evaluation of CTVT (n = 18) in transfected dogs during chemotherapy. Immunohistochemically, tumor phases were investigated by using specific markers (CD3, CD4, CD8, CD79, and transforming growth factor beta [TGF-β]), and investigated an amplified specific sequence of TVT LINE-1 retrotransposon by in situ PCR. Polyhedral-shaped neoplastic cells that had large, round, hypo/hyperchromatic nuclei and eosinophilic cytoplasm were detected. All marker results were positive, especially in the early weeks of recovery. CD4 and TGF-β markers were conspicuously positive at the initial stage. In situ PCR LINE-1 sequence was initially positive in only four cases. It is believed that the CD and TGF-β markers provide phase identification at tumor initiation and during chemotherapy. It is thought that presence of T and B lymphocytes, which have roles in cellular and humoral immunity, is needed so that regression of the tumor is possible.
Animals ; B-Lymphocytes ; Cytoplasm ; Dogs ; Drug Therapy ; Eosinophils ; Immunity, Humoral ; Immunohistochemistry ; Polymerase Chain Reaction ; Retroelements ; Transfection ; Transforming Growth Factor beta ; Venereal Tumors, Veterinary

LINEs (long interspersed nuclear elements or long interspersed repeated DNA elements) contains two open reading frames (ORFs), ORF1 and ORF2. We analysed the ORF2 located in the 5' region to the first exon of oncogene c-myc in canine transmissible venereal tumor (TVT) cell. We also showed the transcription activation was induced by this TVT-LINE sequence using CAT assay. To identify the mutation of tumor suppressor gene, sequence analysis of p53 from TVT cell was performed. We identified the point mutation of 964 nucleotide (T-->C) resulting in the change of amino acid (Phe-->Ser) of p53 tumor suppressor protein.
Amino Acid Sequence ; Animals ; Base Sequence ; Cells, Cultured ; Cricetinae ; DNA, Neoplasm/chemistry/genetics ; Dog Diseases/*genetics ; Dogs ; Long Interspersed Nucleotide Elements/*genetics ; Molecular Sequence Data ; Point Mutation ; Polymerase Chain Reaction ; Sequence Alignment ; Transcription, Genetic ; Tumor Suppressor Protein p53/chemistry/*genetics ; Venereal Tumors, Veterinary/chemistry/*genetics