title: Elevated mammaglobin (h-MAM) expression in breast cancer is associated with clinical and biological features defining a less aggressive tumour phenotype.
abstract: BACKGROUND
  Mammaglobin (h-MAM) is expressed mainly by breast epithelial cells, and this feature has been used to detect circulating breast cancer cells and occult metastases in sentinel axillary lymph nodes of breast cancer patients. However, the biological role of mammaglobin is completely unknown.
  
  
  METHODS
  We studied 128 fresh-frozen breast cancer specimens by means of reverse transcriptase-polymerase chain reaction and quantified their h-MAM mRNA expression. This was then correlated with histological and nuclear grade, oestrogen and progesterone receptor expression, c-erb-B2 and mutant p53 expression, as well as with cellular proliferation measured by means of the Ki67 labelling index, DNA ploidy and S-phase, and finally with the presence or not of invaded axillary nodes in the mastectomy specimen.
  
  
  RESULTS
  In the univariate analysis, high h-MAM expression (above the median for the whole group) correlated significantly (P < 0.05) with oestrogen and progesterone receptor expression, diploid DNA content, low Ki67 labelling index, low nuclear grade and almost significantly (P = 0.058) with the absence of axillary nodal invasion in the mastectomy specimen. In a final, multivariate model, only progesterone receptor expression, diploid DNA content and absence of nodal invasion were found to be independently associated with high h-MAM expression.
  
  
  CONCLUSIONS
  All of the features associated with mammaglobin expression reflect, without exception, a less aggressive tumour phenotype. Further studies are needed to clarify whether this is attributable to h-MAM expression itself, or to another mechanism of which mammaglobin expression forms part.
authors.affiliation: Fundación Tejerina-Centro de Patología de la Mama, Madrid, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Núñez-Villar
authors.forename: F
authors.initials: F
authors.lastname: Martínez-Arribas
authors.forename: M
authors.initials: M
authors.lastname: Pollán
authors.forename: A R
authors.initials: AR
authors.lastname: Lucas
authors.forename: J
authors.initials: J
authors.lastname: Sánchez
authors.forename: A
authors.initials: A
authors.lastname: Tejerina
authors.forename: J
authors.initials: J
authors.lastname: Schneider
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000473:pathology; D018275:Carcinoma, Lobular / Q000235:genetics / Q000473:pathology; D004171:Diploidy; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics / Q000502:physiology; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D060785:Mammaglobin A; D009362:Neoplasm Metastasis / Q000235:genetics / Q000473:pathology; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D010641:Phenotype; D011980:Receptors, Progesterone / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014598:Uteroglobin / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology
chemical_list: D060785:Mammaglobin A; D009363:Neoplasm Proteins; D011980:Receptors, Progesterone; C556448:SCGB2A2 protein, human; D014598:Uteroglobin