Breast cancer is a common malignant tumor. According to the Report of Breast Disease in China published by Chinese Population Association in 2010, the number of breast cancer patients in China was estimated to be over 200,000. Every year, about 15 percent of 1,300,000 new cases over the world were from China. High work pressure and modern diet led to a rapid increase of breast cancer patients in China urban area, especially in young women. It is essential to develop suitable animal models for discovering novel preventive and therapeutic approaches.
Rodents are commonly used for studying the mechanism and developing anti-cancer drugs of breast cancer. However, the rodent is far away from human in genetic evolution, anatomy, physiology, and organ systems. Non-human primates (NHPs) may be better animal models for human cancer research because NHPs and human beings are similar in terms of the genetic evolution, the immune system, physiology, and metabolism. Tree shrews (Tupaia belangeri chinensis) are considered as primate-like animals having a closer evolutionary relationship with human being than rodents; therefore, it may be used as a new animal model for investigating breast cancer.
The wild tree shrews were mainly distributed in Southeast Asia and Southwest China. They have been artificially propagated for decades. Although the first report about spontaneous tree shrew breast tumors was published in 1966, there are no detailed studies. Dr. XIA Houjun, Ms. WANG Chunyan and their colleagues from the group of cancer biology at Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences, Kunming Institute of Zoology, Chinese Academy of Sciences, characterized a spontaneous tree shrew breast tumor. This tumor was identified as papillary tumor through the Haematoxylin Eosin (H&E) staining. Immunohistochemical staining (IHC) for progesterone receptor (PR)，Human Epidermal Growth Factor Receptor 2 (Her-2), Ki-67 and cleaved caspase-3 (Cl-C3) showed that tumor cells are positive for PR, negative for Her-2，highly proliferative and less apoptotic. This study will not only help us to understand the basic features of tree shrew breast cancer but also will provide a valuable clue for developing tree shrew experimental breast cancer models.
The study was led by Profs. CHEN Ceshi (KIZ, the CAS) and JIAO Jianlin (Kunming Medical College). The study was partially funded by a grant from the Chinese Academy of Sciences, Basic Frontier Project (KSCX2-EWJ-23) and a grant from Yunnan Province High-Profile Talent Project (2010CI114).
The main findings of this study have been published on Zoological Research (2012，Feb. 33(1): 55−59, DOI: 10.3724/SP.J.1141.2012.01055).
