title: Murine mammary tumor cells with a claudin-low genotype.
abstract: BACKGROUND
  Molecular classification of human breast cancers has identified at least 5 distinct tumor subtypes; luminal A, luminal B, Her2-enriched, basal-like and claudin-low. The claudin-low subtype was identified in 2007 and is characterized by low expression of luminal differentiation markers and claudins 3, 4 and 7 and high levels of mesenchymal markers. Claudin-low tumors have a reported prevalence of 7-14% and these tumors have a poor prognosis.
  
  
  RESULTS
  In this study we report the characterization of several cell lines established from mammary tumors that develop in MTB-IGFIR transgenic mice. Two lines, RM11A and RJ348 present with histological features and gene expression patterns that resemble claudin-low breast tumors. Specifically, RM11A and RJ348 cells express high levels of the mesenchymal genes Zeb1, Zeb2, Twist1 and Twist2 and very low levels of E-cadherin and claudins 3, 4 and 7. The RM11A and RJ348 cells are also highly tumorigenic when re-introduced into the mammary fat pad of mice.
  
  
  CONCLUSIONS
  Mammary tumor cells established from MTB-IGFIR transgenic mice can be used as in vitro and in vivo model systems to further our understanding of the poorly characterized, claudin-low, breast cancer subtype.
authors.affiliation: Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON N1G2W1, Canada. rmoorehe@uoguelph.ca.
authors.forename: Craig I
authors.initials: CI
authors.lastname: Campbell
authors.forename: Devan E
authors.initials: DE
authors.lastname: Thompson
authors.forename: Megan D
authors.initials: MD
authors.lastname: Siwicky
authors.forename: Roger A
authors.initials: RA
authors.lastname: Moorehead