title: Mouse mammary tumor-like virus (MMTV) is present in human breast tissue before development of virally associated breast cancer.
abstract: BACKGROUND
  There is substantial evidence that a virus homologous to mouse mammary tumor virus (MMTV) may have a role in human breast cancer. The present study indicates that those who developed breast cancer associated with an MMTV-like virus had this virus in their non-cancerous breast tissues years before the cancer developed.
  
  
  METHODS
  Polymerase chain reaction (PCR) techniques and sequencing were used to identify MMTV-like envelope gene sequences (MMTV-likeenvsequences) in Australian benign breast biopsy specimens from women who several years later developed breast cancer. Murine contamination was excluded by stringent laboratory procedures, and the absence of intracisternal A particle sequences and mitochondrial cyclooxygenase sequences.
  
  
  RESULTS
  MMTV-likeenvsequences (also called HMTV sequences to denote their source) were found in 9 of 25 breast cancer specimens (36%). Among 25 non-cancerous breast biopsies of these same patients taken 1 to 11 years earlier, six contained MMTV-like sequences (24%). Five of the six were among the nine virally-associated breast cancers. In two pairs of specimens, benign and malignant,envsequences were 97% identical.
  
  
  CONCLUSIONS
  The identification of MMTV (MMTV-like) sequences in breast tissues prior to the development of MMTV positive breast cancer fulfills a key criterion for a possible causal role for the MMTV-like virus in human breast cancer.
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY USA.
authors.forename: Teiko
authors.initials: T
authors.lastname: Nartey
authors.affiliation: Department of Pathology, University of Pisa, Pisa, Italy.
authors.forename: Chiara M
authors.initials: CM
authors.lastname: Mazzanti
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY USA.
authors.forename: Stella
authors.initials: S
authors.lastname: Melana
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.
authors.forename: Wendy K
authors.initials: WK
authors.lastname: Glenn
authors.affiliation: Department of Pathology, University of Pisa, Pisa, Italy.
authors.forename: Generoso
authors.initials: G
authors.lastname: Bevilacqua
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Holland
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.
authors.forename: Noel J
authors.initials: NJ
authors.lastname: Whitaker
authors.affiliation: School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia.
authors.forename: James S
authors.initials: JS
authors.lastname: Lawson
authors.affiliation: Icahn School of Medicine at Mount Sinai, New York, NY USA.
authors.forename: Beatriz G T
authors.initials: BG
authors.lastname: Pogo
keywords: Benign breast tissues; Breast cancer; HMTV; Histological; Histotype; Human mammary tumour virus; MMTV; MMTV-like; Morphological; Morphology; Mouse mammary tumor virus; Mouse mammary tumor-like virus