Vitamin D receptor expression in canine mammary gland and relationship with clinicopathological parameters and progesterone/oestrogen receptors

Abstract

The vitamin D receptor (VDR) belongs to the nuclear class II receptor family. VDR is a ligand transcription factor and mediates the actions of calcitriol, the active product of vitamin D synthesis. Nowadays, it is known that the biological actions of calcitriol include the capacity to modulate cancer features, such as proliferation and differentiation, apoptosis, angiogenesis, invasion and metastasis. VDR expression has been demonstrated in human breast cancer and vitamin D has emerged as a promising targeted therapy. We analyse the VDR expression in normal and neoplastic canine mammary tissue samples and its relationship with clinicopathological parameters and progesterone/oestrogens receptors (PR/ER). Expression of VDR, Ki67 (to evaluate the proliferation index, PI), PR and ER was assessed in 50 mammary gland tissue samples from 41 female dogs by immunohistochemistry. VDR-positive staining was found in the nuclei of both myoepithelial and luminal epithelial cell layers. VDR expression was higher in normal mammary tissue (37/37 cases, 100%) then followed by benign tumours (6/15 cases, 40%) and malignant tumours (9/34 cases, 26.5%) (P = .001). Female dogs aged ≥10 years had lower VDR expression compared with dogs younger (P = .017). Relationship between VDR and breed, number of tumours, tumour size, histologic subtype, histologic grade of malignancy, PI and PR and ER expression was not observed. Studies with more samples are necessary to further evaluate the possible role of VDR in the biological behaviour of canine mammary tumours, and to corroborate the possibility to use the dog as model for human breast cancer.

Serum 25‐hydroxyvitamin D, vitamin D receptor, and vitamin D binding protein concentrations in dogs with acute pancreatitis compared to healthy control dogs

“…47 In our study, age was not correlated with serum 25(OH)D and VDBP concentrations in healthy dogs (data not shown), and it is unlikely that the results were affected by age. Although the influence of age on VDR expression in the parathyroid glands of humans 48 and mammary glands in female dogs has been reported, 49 age and serum VDR concentrations in healthy dogs were not correlated in our study (data not shown). Third, we could not evaluate some factors that regulate calcium homeostasis, such as calcitonin and magnesium.…”

Effect of vitamin D3 on hyperplasia of mammary glands in experimental rats

“…VDR is the intracellular receptor for VD3, a steroid hormone receptor that is essential for normal mammary gland development (22). Recent studies have shown that VD3 can induce apoptosis, block cell cycle, and inhibit tumor cell proliferation through its receptor VDR in many ways (23)(24)(25). In wild type cells, low dose of VD3 could induce G0/G1 cycle arrest and apoptosis, while VDR knockout cells did not produce cell cycle arrest and apoptosis even under the action of high dose of VD3.…”

Influence of VDR gene polymorphisms on the development and course of breast cancer

“…На сьогоднішній день кількість знайдених SNP у VDR перевалює за 400, однак, кореляційний зв'язок із раком молочної залози було знайдено у поліморфізмів FokI (rs2228570), BsmI (rs1544410), TaqI (rs731236), та ApaI (rs7975232) [31,35].…”