title: Establishment of novel rat models for premalignant breast disease.
abstract: BACKGROUND
  Breast cancer has become one of the most common malignant tumors among females over the past several years. Breast carcinogenesis is a continuous process, which is featured by the normal epithelium progressing to premalignant lesions and then to invasive breast cancer (IBC). Targeting premalignant lesions is an effective strategy to prevent breast cancer. The establishment of animal models is critical to study the mechanisms of breast carcinogenesis, which will facilitate research on breast cancer prevention and drug behaviors. In this study, we established a feasible chemically-induced rat model of premalignant breast cancer.
  
  
  METHODS
  Following the administration of the drugs (carcinogen, estrogen, and progestogen) to Sprague-Dawley (SD) rats, tumors or suspicious tumors were identified by palpation or ultrasound imaging, and were surgically excised for pathological evaluation. A series of four consecutive steps were carried out in order to determine the carcinogen: 7,12-dimethylbenzaanthracene (DMBA) or 1-methyl-1-nitrosourea, the route of carcinogen administration, the administration period of estrogen and progestogen, and the DMBA dosage.
  
  
  RESULTS
  Stable premalignant lesions can be induced in SD rats on administration of DMBA (15 mg/kg, administered three times) followed by administration of female hormones 5-day cycle.
  
  
  RESULTS
  were confirmed by ultrasound and palpation.
  
  
  CONCLUSIONS
  Under the premise of drug dose and cycle, DMBA combined with estrogen and progestogen can be used as a SD rat model for breast premalignant lesions.
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Zhongbing
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Qinye
authors.initials: Q
authors.lastname: Fu
authors.affiliation: Department of General Surgery, the Sixth People's Hospital of Jinan City, Jinan, Shandong 250200, China.
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Fang
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Dezong
authors.initials: D
authors.lastname: Gao
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China.
authors.forename: Lixiang
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Breast Disease, the Second Hospital of Shandong University, Jinan, Shandong 250033, China. Email: yzg@medmail.com.cn.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yu
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D001941:Breast Diseases / Q000139:chemically induced*; D004195:Disease Models, Animal; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene