Immunohistochemical evaluation of estrogen and progesterone receptors in transmissible venereal tumour and vaginal tissues of affected and non-affected bitches in different estrous phases

Author(s)

Claudia Prado de Brito

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2004-07-02

Examining board members

Clair Motos de Oliveira; Maria Lucia Zaidan Dagli; Maria Denise Lopes

• Advisor: Clair Motos de Oliveira

Abstract

One of the most frequent canine neoplasias is the Transmissible Venereal Tumour (TVT) which affects male and female genital tract. In clinical routine the standard treatment is chemotherapy, to which nevertheless drug resistance is a common feature. Immunohistochemical determination of steroid hormone receptors (estrogen and progesterone) in normal and tumoral tissues of humans and several other species is of great relevance for prognostic evaluation of oncological patients, as well as for the decision of whether to make use of hormonal therapy in association to chemotherapy. The aim of this research was to determine immunohistochemically estrogen (ER-α) and progesterone (PR4) receptors expression in vaginal tissue of non-affected bitches and in vaginal and tumoral tissues of TVT affected bitches. Fifty-eight bitches were equally divided in 2 groups: experimental group (TVT) and control group (non-affected). Canine estrous cycle phases were determined by means of vaginal cytology, hormonal assay and macroscopic appearance of ovaries. Samples from vaginal and tumoral tissues were obtained with bitches submitted to general anesthesia. Samples were fixed in 10% buffered formaldehyde and then mounted in paraffin-embedded sections. Anestrous, proestrous and estrous control females presented higher ER-α expression than diestrous bitches. Within the experimental group, there was statistical difference between estrous and diestrous phases, being ER-α expression higher for diestrous bitches. However, no significant difference in relation to anestrous females was established. In relation to RP4 expression, no difference among estrous cycle phases of the control group was verified. Furthermore, no RP4 expression was noted in vaginal tissue of TVT affected females. In tumoral tissues ER-α and RP4 were not expressed, although some samples presented ER-α expression in blood vessels’ endothelium. In conclusion, different ER-α expression was verified in vaginal tissue of experimental and control bitches under distinct steroid influence, whereas no ER-α expression in tumoral tissues was evidenced (AU)