Overexpression of the EGF receptor-related proto-oncogene erbB-2 in human mammary tumor cell lines by different molecular mechanisms

EMBO J. 1987 Mar;6(3):605-10.


Amplification of the erbB/EGF receptor and a structurally related gene, designated erbB-2, have previously been detected in a variety of human tumors. In a series of human mammary tumor cell lines, analysis of transcripts of these genes revealed elevated levels of one or the other in more than 60% of tumors analyzed. Eight cell lines demonstrated erbB-2 mRNA levels ranging from 4- to 128-fold above those of normal controls. erbB-2 expression was evaluated in comparison to the expression level of actin observed in these cell lines. There was no evidence of an aberrantly sized erbB-2 transcript in any of these lines. Immunoblot analysis indicated elevation in levels of the 185-kd product of the erbB-2 gene expressed by these cells. In four lines erbB-2 gene amplification in the absence of an apparent gene rearrangement was demonstrated. In a representative cell line of this type, SK-BR-3, the amplified erbB-2 gene copies were located in an aberrant chromosomal location. Four additional cell lines, which demonstrated 4- to 8-fold overexpression of erbB-2 mRNA, did not exhibit gene amplification. In a representative cell line of this type ZR-75-1, an apparently normal chromosomal location was found for the erbB-2 gene. Our findings indicate that overexpression of the erbB-2 gene in mammary tumor cell lines is frequent and associated with different genetic abnormalities.

MeSH terms

  • Breast Neoplasms
  • Cell Line
  • Chromosome Banding
  • DNA / isolation & purification
  • DNA Restriction Enzymes
  • ErbB Receptors / genetics*
  • Female
  • Gene Amplification*
  • Genes*
  • Humans
  • Metaphase
  • Proto-Oncogenes*
  • RNA, Messenger / genetics
  • Transcription, Genetic


  • RNA, Messenger
  • DNA
  • ErbB Receptors
  • DNA Restriction Enzymes