Genetic lesions remain stable in xenograft cells. A copy number heat map was produced from log₂ ratio Affymetrix SNP Version 6.0 analyses of 6 ALL patients and their corresponding xenografts of up to 3 subsequent amplification rounds. All CNAs of > 100 kb in size were included, also showing Ig/TCR gene rearrangements. Dx indicates diagnostic sample; and 1st, 2nd, and 3rd indicates first, second, and third amplification round, respectively. *The xenografts were obtained from transplantations with 100 cells.