High prevalence of benign mammary tumors in a rat model of polycystic ovary syndrome during postmenopausal period

Abstract

Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in reproductive-age women. Significant associations between PCOS and benign breast diseases (BBD) and a possibly potential association between PCOS and breast cancer have been reported. The etiology of these events of mammary glands in PCOS remains unclear. Animal models that show BBD and breast cancer may contribute to further understanding about these diseases. We aimed to examine the spontaneous occurrence of mammary tumors, their prevalence, and type in our rat model of PCOS. Prenatal androgen-induced PCOS rats and controls were examined in later life. Benign mammary tumors were observed in 75% and 33.33% of PCOS rats and controls during the postmenopausal period, respectively (p = .0158). Mammary tumors were non-invasive, margins of excision were normal and tumors were freely movable, in both groups. After microscopic evaluations of tumors, proliferative breast lesions and adenomas with a tubular growth pattern were observed in both groups. However, in PCOS rats, of benign tumors two had a mixed pattern of fibroadenoma/fibroma and cysts. High prevalence of benign mammary tumors was observed in our rat model of PCOS during the postmenopausal period, possibly due to hormonal imbalances during their reproductive lifespan; this model may contribute to current data available regarding the events of mammary glands in PCOS.

摘要

多囊卵巢综合征（PCOS）是育龄期女性最常见的内分泌紊乱性疾病之一。已经报道了PCOS与良性乳腺疾病（BBD）之间的显著关系, 以及PCOS与乳腺癌之间可能的潜在关系。PCOS患者乳腺疾病的病因尚不清楚。BBD和乳腺癌的动物模型可能有助于进一步了解这些疾病。我们的目的是评估PCOS大鼠模型中乳腺肿瘤的自发发生率、患病率和类型。在大鼠晚年评估产前雄激素诱导的PCOS大鼠组和对照组。绝经后期PCOS大鼠组和对照组中分别观察到有75％和33.33％出现了良性乳腺肿瘤（p = 0.0158）。在两组中, 乳腺肿瘤均为非侵入性, 切除边缘正常, 肿瘤可自由推动。在对肿瘤进行显微镜下评估后, 两组中观察到增生性乳腺病变和具有管状生长模式的腺瘤。然而, 在PCOS大鼠中, 良性肿瘤中有两种纤维腺瘤或纤维瘤和囊肿的混合模式。 在PCOS大鼠模型的绝经后期观察到良性乳腺肿瘤的高患病率, 可能是由于生殖期的激素失衡, 该模型可能有助于获得关于PCOS患者乳腺疾病的现有数据。

The Chinese abstracts are translated by Prof. Dr. Xiangyan Ruan and her team: Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing 100026, China.

Keywords:

• Benign mammary tumors
• polycystic ovary syndrome
• aging
• rat model

Acknowledgements

The authors wish to acknowledge Mrs Niloofar Shiva for critical editing of English grammar and syntax of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.