Breast Cancer
Parity-induced mammary epithelial cells promote tumor growth in transgenic mice

   2004 NOV 22 - ( -- Parity-induced mammary epithelial cells promote tumorigenesis in mouse mammary tumor virus (MMTV)-neu transgenic mice, report oncologists at the University of Nebraska.

   M.D. Henry and colleagues announced, "Using a Cre-lox-based genetic labeling technique, we have recently discovered a parity-induced mammary epithelial subtype that is abundant in nonlactating and nonpregnant, parous females.

   "These mammary epithelial cells serve as alveolar progenitors in subsequent pregnancies, and transplantation studies revealed that they possess features of multipotent progenitors such as self-renewal and the capability to contribute to ductal and alveolar morphogenesis," the researchers said.

   Writing in the journal Oncogene, they "[reported] that these cells are the cellular targets for transformation in MMTV-neu transgenic mice that exhibit accelerated mammary tumorigenesis in multiparous animals."

   "The selective ablation of this epithelial subtype reduces the onset of tumorigenesis in multiparous MMTV-neu transgenics," Henry and colleagues wrote.

   "There is, however, experimental evidence to suggest that parity-induced mammary epithelial cells may not be the only cellular targets in other MMTV-promoter-based transgenic strains. In particular, the heterogeneous MMTV-wnt1 lesions predominantly express the ductal differentiation marker Nkcc1 that is absent in MMTV-neu-derived tumors," the team reported.

   They concluded, "Our observations support the idea that tumors originate from distinctly different epithelial subtypes in selected MMTV-promoter-driven cancer models and that diverse oncogenes might exert discrete effects on particular mammary epithelial subtypes."

   Henry and coauthors published their study in Oncogene (Parity-induced mammary epithelial cells facilitate tumorigenesis in MMTV-neu transgenic mice. Oncogene, 2004;23(41):6980-6985).

   For additional information, contact K.U. Wagner, University of Nebraska, Med Center, Eppley Institute Research Cancer and Allied Diseases, 986805 Nebraska Med Center, Room 8009, Omaha, NE 68198, USA.

   The publisher of the journal Oncogene can be contacted at: Nature Publishing Group, Macmillan Building, 4 Crinan St., London N1 9XW, England.

   The information in this article comes under the major subject areas of Breast Cancer, Tumorigenesis, Mouse Mammary Tumor Virus, Animal Models, Oncogenes, and Mammary Epithelial Subtypes.

   This article was prepared by Health & Medicine Week editors from staff and other reports. Copyright 2004, Health & Medicine Week via

     Health & Medicine Week, November 22, 2004, page 142