Purpose: This collaboration of five established European gene expression labs investigated the potential
impact of culture conditions on the transcriptional response of peripheral blood to radiation exposure.
Materials and methods: Blood from one healthy donor was exposed ex vivo to a Cobalt 60 source to
produce a calibration curve in addition to four unknown doses. After exposure, the blood samples
were either diluted with RPMI medium or left untouched. After 24-h incubation at 37 C the diluted
blood samples were lysed, while the undiluted samples were mixed with the preservative RNALater
and all samples were shipped frozen to the participating labs. Samples were processed by each lab
using microarray (one lab) and QRT-PCR (four labs).
Results: We show that although culture conditions affect the total amount of RNA recovered
(p0.5 Gy) measurements (p�.6).
Conclusion: This study confirms the robustness of gene expression as a method for biological