Mouse Genome Informatics
cx
    Tg(MMTV-rtTA)1Lach/0
Tg(tetO-MYC)1Lach/0

involves: FVB
Key:
phenotype observed in females
phenotype observed in males
N normal phenotype
tumorigenesis
• chronically doxycycline induced females develop mammary tumors with high penetrance (86%) following an average of 22 weeks of induction
• mammary tumors in chronically doxycycline induced females are invasive mammary adenocarcinomas
• withdrawal of doxycycline from chronically induced tumor-bearing mutants results in rapid regression of a subset of invasive mammary adenocarcinomas (14 days) but another subset of tumors decrease in size but then resume growth
• tumors that continue to grow after doxycycline removal show undetectable expression of the MYC transgene but increased endogenous Myc expression and exhibit mutations in Kras or Nras

integument
• mammary glands of mutants induced with doxycycline for 4 months exhibit atypical lobuloalveolar growths (dysplasia)
• non-tumor bearing mammary glands of mutants induced with doxycycline for 30 weeks (chronically induced) exhibit numerous epithelial hyperplasts and dysplasts, however when doxycycline is withdrawn for 12 weeks, most epithelial ducts appear normal
• mammary glands of mutants induced with doxycycline for 30 days are hyperplastic
• mammary glands of mutants induced with doxycycline for 4 months exhibit focal hyperplasia
• mammary epithelium of mutants induced with doxycycline exhibits increased apoptosis
• mammary epithelium of mutants induced with doxycycline exhibits increased proliferation

endocrine/exocrine glands
• mammary glands of mutants induced with doxycycline for 4 months exhibit atypical lobuloalveolar growths (dysplasia)
• non-tumor bearing mammary glands of mutants induced with doxycycline for 30 weeks (chronically induced) exhibit numerous epithelial hyperplasts and dysplasts, however when doxycycline is withdrawn for 12 weeks, most epithelial ducts appear normal
• mammary glands of mutants induced with doxycycline for 30 days are hyperplastic
• mammary glands of mutants induced with doxycycline for 4 months exhibit focal hyperplasia
• mammary epithelium of mutants induced with doxycycline exhibits increased apoptosis
• mammary epithelium of mutants induced with doxycycline exhibits increased proliferation

cellular
• mammary epithelium of mutants induced with doxycycline exhibits increased proliferation

Mouse Models of Human Disease
OMIM IDRef(s)
Breast Cancer 114480 J:67498