Mouse Genome Informatics
cx
    Tg(MMTV-rtTA)1Lach/0
Tg(tetO-Esr1)#Paf/0

involves: FVB/N
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
endocrine/exocrine glands
• exposure to exogenous estrogen does not increase or change the prevalence of ductal abnormalities, proliferative disease or ductal carcinoma in situ
• neither hyperplasia nor ductal carcinoma in situ regress within a 2-week period following doxycycline treatment in 4 month old mutants
• ovariectomized mice do not show ductal hyperplasia, ductal carcinoma in situ or other ductal abnormalities
• mutants which were treated with doxycycline at 3 weeks of age to inhibit Esr1 expression exhibit normal mammary gland development
• at 4 months of age, mutants show abnormal mammary ductal structures, including lateral budding, dilated ducts, and abnormal branching
• at 4 months of age, mutants show lateral budding and abnormal branching of mammary gland ducts
• 33% and 36% of mutants at 2 and 4 months of age, respectively, show ductal hyperplasia
• rates of mammary epithelial cell proliferation are increased compared to controls
• 52% of mutants at 4 months of age show lobular hyperplasia
• 12 month old mice display hyperplastic alveolar nodules with increased frequency of mitotic figures within the hyperplasias

tumorigenesis
• 17% and 21% of mutants at 2 and 4 months of age, respectively, develop ductal carcinoma in situ

integument
• exposure to exogenous estrogen does not increase or change the prevalence of ductal abnormalities, proliferative disease or ductal carcinoma in situ
• neither hyperplasia nor ductal carcinoma in situ regress within a 2-week period following doxycycline treatment in 4 month old mutants
• ovariectomized mice do not show ductal hyperplasia, ductal carcinoma in situ or other ductal abnormalities
• mutants which were treated with doxycycline at 3 weeks of age to inhibit Esr1 expression exhibit normal mammary gland development
• at 4 months of age, mutants show abnormal mammary ductal structures, including lateral budding, dilated ducts, and abnormal branching
• at 4 months of age, mutants show lateral budding and abnormal branching of mammary gland ducts
• 33% and 36% of mutants at 2 and 4 months of age, respectively, show ductal hyperplasia
• rates of mammary epithelial cell proliferation are increased compared to controls
• 52% of mutants at 4 months of age show lobular hyperplasia
• 12 month old mice display hyperplastic alveolar nodules with increased frequency of mitotic figures within the hyperplasias

Mouse Models of Human Disease
OMIM IDRef(s)
Breast Cancer 114480 J:96383