Expression of mammary tumor virus proteins in preneoplastic outgrowth lines and mammary tumors of BALB/cV mice

Cancer Res. 1984 May;44(5):2155-62.


A subline of BALB/c mice, designated BALB/cV, has been segregated which exhibits an intermediate mammary tumor incidence and which harbors a unique milk-transmitted virus. Six stable hyperplastic alveolar nodule outgrowth lines were established from chemical carcinogen-treated and hormonally stimulated mice. Tumor incidences exhibited by the individual preneoplastic lines ranged from 22 to 95%; no differences in tumor-producing capability were observed when lines were transplanted in virus-negative (BALB/c) or virus-positive (BALB/cV) animals. Viral antigen expression was monitored using antisera prepared against C3H mouse mammary tumor virus (MMTV) proteins. The preneoplastic lines exhibited more virus antigenpositive cells in a peroxidase-antiperoxidase immunocytochemical assay than did primary tumors which arose from the hyperplastic alveolar nodule transplants. Analysis of BALB/cV preneoplastic and tumor tissue by metabolic labeling and by protein electroblotting methodologies revealed that viral precursor and structural proteins were expressed in both types of tissue; the polypeptides were similar in molecular weight to those encoded by exogenous MMTVs. These studies demonstrate that the coding capacity of the BALB/cV isolate of MMTV is similar to that of known MMTV isolates and that each of the BALB/cV structural polypeptides shares group-specific antigenic determinants with the analogous protein encoded by MMTV from the C3H mouse. The hyperplastic outgrowth lines established in the BALB/cV subline provide an additional system for the study of mammary tumorigenesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Line
  • Female
  • Immune Sera
  • Mammary Neoplasms, Experimental / microbiology*
  • Mammary Tumor Virus, Mouse / genetics*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred Strains
  • Precancerous Conditions / microbiology*
  • Viral Proteins / genetics*
  • Viral Proteins / isolation & purification


  • Immune Sera
  • Viral Proteins