title: Effects of low-dose ionizing radiation on gene expression in human skin biopsies.
abstract: OBJECTIVE
  Several investigations have demonstrated that significant biologic effects can occur in animals, animal cells, immortalized human cell lines, and primary human cells after exposure to doses of ionizing radiation in the low-dose, < or =1-10 cGy region (LDIR). However, little information is available as to how these and other observations pertain to human responses to LDIR, though such knowledge is required for reducing the uncertainty of assessing human risks due to these exposures. We therefore undertook these translational studies to begin the development of a unique data set of human cellular responses to LDIR as measured by gene expression changes when exposure occurs to a normal tissue with its complex cellular mixture and three-dimensional architecture.
  
  
  METHODS
  Using full-thickness human skin resected during esthetic surgery, we obtained biopsy cores and exposed the tissue to LDIR ex vivo. Gene expression changes in five core regulatory genes were assessed by real-time RT-PCR.
  
  
  RESULTS
  Results indicate that skin is a good biologic model for assessing LDIR in humans, though meticulous attention to sample processing is necessary. LDIR does produce changes in gene expression, though time- and dose-response relationships may be complex.
  
  
  CONCLUSIONS
  These proof-of-principle studies have provided a crucial initial step toward validation of LDIR risk assessment models in humans. We have demonstrated the feasibility of this approach and provide initial evidence that ionizing radiation exposures as low as 1 cGy are biologically active in human skin.
authors.affiliation: Department of Radiation Oncology, University of California at Davis, UC Davis Cancer Center, 4501 X Street, Suite G-126, Sacramento, CA 95817, USA. zgoldberg@ucdavis.edu
authors.forename: Zelanna
authors.initials: Z
authors.lastname: Goldberg
authors.forename: Chad W
authors.initials: CW
authors.lastname: Schwietert
authors.forename: Bruce
authors.initials: B
authors.lastname: Lehnert
authors.forename: Robin
authors.initials: R
authors.lastname: Stern
authors.forename: Io
authors.initials: I
authors.lastname: Nami
mesh_terms: D001706:Biopsy; D004307:Dose-Response Relationship, Radiation; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D011829:Radiation Dosage; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012867:Skin / Q000528:radiation effects*