title: Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues.
abstract: BACKGROUND
  During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS) are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH), ductal carcinoma in situ (DCIS) and invasive breast cancer (IBC).
  
  
  METHODS
  Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue.
  
  
  RESULTS
  We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue.
  
  
  CONCLUSIONS
  Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells.
authors.affiliation: Department of Molecular and Integrative Physiology, University of Illinois, Urbana IL 61801, USA.
authors.forename: Carol D
authors.initials: CD
authors.lastname: Curtis
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Thorngren
authors.forename: Ann M
authors.initials: AM
authors.lastname: Nardulli
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology; D045744:Cell Line, Tumor; D004249:DNA Damage; D004260:DNA Repair; D018450:Disease Progression; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D015674:Mammary Neoplasms, Animal / Q000378:metabolism*; D008954:Models, Biological; D018384:Oxidative Stress; D017382:Reactive Oxygen Species
chemical_list: D017382:Reactive Oxygen Species