title: Progression from normal breast pathology to breast cancer is associated with increasing prevalence of mouse mammary tumor virus-like sequences in men and women.
abstract: Mouse mammary tumor virus (MMTV)-like sequences have been found in up to 40% of breast cancer samples but in <2% of normal breast tissue samples from Australian women studied by our group. Screening of a larger and more diverse cohort of female breast cancer samples has now shown a correlation of MMTV-like sequences with the severity (grade) of breast cancer. Thirty-two percent (43 of 136) of female breast cancer samples were positive for MMTV-like sequences when screened using PCR. A significant gradient of MMTV positivity was observed with increasing severity of cancer from 23% of infiltrating ductal carcinoma (IDC) grade I tumors to 34% of IDC grade II tumors (P = 0.00034) and 38% of IDC grade III tumors (P = 0.00002). We also report for the first time the detection of MMTV-like sequences in 62% (8 of 13) of male breast cancer samples and 19% (10 of 52) of male gynecomastia samples screened. MMTV-like sequences were demonstrated in various premalignant breast lesions of females, including fibroadenoma (20%) and fibrocystic disease (28%) samples, at a significantly higher prevalence than that seen in normal breast tissue (1.8%; P = 0.00001). Study of a longitudinal cohort of female breast cancer patients indicated that MMTV was co-incident with tumor but was not present when tumor was absent on histology. These results support the association of MMTV-like sequences with development of breast tumors in men and women and suggest association of MMTV with increasing severity of cancer.
authors.affiliation: Virology Division, Department of Microbiology, South Eastern Area Laboratory Services, Prince of Wales Hospital, Randwick, New South Wales 2031, Australia.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Ford
authors.forename: Margaret
authors.initials: M
authors.lastname: Faedo
authors.forename: Roger
authors.initials: R
authors.lastname: Crouch
authors.forename: James S
authors.initials: JS
authors.lastname: Lawson
authors.forename: William D
authors.initials: WD
authors.lastname: Rawlinson
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001940:Breast / Q000166:cytology; D001943:Breast Neoplasms / Q000235:genetics / Q000821:virology*; D018567:Breast Neoplasms, Male / Q000235:genetics / Q000821:virology*; D002278:Carcinoma in Situ / Q000235:genetics / Q000821:virology; D044584:Carcinoma, Ductal / Q000235:genetics / Q000821:virology; D002472:Cell Transformation, Viral / Q000235:genetics*; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics*; D051379:Mice; D008875:Middle Aged; D041681:NIH 3T3 Cells; D011230:Precancerous Conditions / Q000235:genetics / Q000821:virology*; D012737:Sex Factors