Glioblastomas treated with the DNA alkylating agent temozolomide develop temozolomide-resistance driven by augmented homologous recombination. The cover image shows chromosomes from a temozolomide-resistant tumor. Tumor cells were cultured in BrdU, and treated with a DNA-damaging drug. Metaphase spreads were prepared from the treated cells, and chromosomes were stained with acridine orange (green). The chromosomes exhibit high numbers of sister chromatid exchanges which indicates high levels of homologous recombination repair of drug-induced DNA double-strand breaks. For more information, see the article by Gil del Alcazar and colleagues beginning on page 928.