In order to identify chr2 deletions and Sfpi.1/PU.1 loss, we per-formed array comparative genomic hybridization (aCGH) on a unique panel of 79rANLs.Using a custom made CGH array specifically designed for mouse chr2, we analysed at unprecedentedly high resolution (1.4 M array-148 bp resolution) the size of the MDR in low LET and high-LET induced rAMLs (32 X-ray-ane 47 neutron-induced).