title: ABCG2 is associated with HER-2 expression, lymph node metastasis and clinical stage in breast invasive ductal carcinoma.
abstract: BACKGROUND
  ABCG2 is an ABC transporter. It has been demonstrated that endogenous ABCG2 expression in certain cancers is a possible reflection of the differentiated phenotype of the cell of origin and likely contributes to intrinsic drug resistance. But little is known about the contribution of ABCG2 to the drug resistance and the clinicopathological characteristics in breast cancer. In the present study, we investigated the expression of ABCG2 and the correlations between ABCG2 expression and patients' clinicopathological and biological characteristics.
  
  
  METHODS
  Immunohistochemistry was employed on the tissue microarray paraffin sections of surgically removed samples from 196 breast cancer patients with clinicopathological data.
  
  
  RESULTS
  The results showed that ABCG2 was expressed in different intensities and distributions in the tumor cells of the breast invasive ductal carcinoma. A positive stain for ABCG2 was defined as a brown stain observed in the cytoplasm and cytomembrane. A statistically significant correlation was demonstrated between ABCG2 expression and HER-2 expression (p = 0.001), lymph node metastasis (p = 0.049), and clinical stage (p = 0.015) respectively.
  
  
  CONCLUSIONS
  ABCG2 correlated with Her-2 expression, lymph node metastasis and clinical stage in breast invasive ductal carcinoma. It could be a novel potential bio-marker which can predict biological behavior, clinical progression, prognosis and chemotherapy effectiveness.
authors.affiliation: Department of Pathology, Shandong University School of Medicine, 44, Wenhua Xi Road, Ji'nan, Shandong Province, P,R,China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xiang
authors.forename: Peng
authors.initials: P
authors.lastname: Su
authors.forename: Shujun
authors.initials: S
authors.lastname: Xia
authors.forename: Zhiyan
authors.initials: Z
authors.lastname: Liu
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.forename: Peng
authors.initials: P
authors.lastname: Gao
authors.forename: Genyin
authors.initials: G
authors.lastname: Zhou
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis / Q000473:pathology*; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D046888:Tissue Array Analysis
chemical_list: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; C116614:ABCG2 protein, human