Clinical management of triple-negative breast cancer (TNBC) relies heavily on the use of cytotoxic chemotherapy but acquired resistance to these interventions is common. The cover depicts array comparative genomic hybridization analysis of TNBC cells which had been cultured in the presence of the topoisomerase-2 inhibitor doxorubicin (DOXO). DOXO-resistant cells from multiple clones acquired recurrent chromosomal copy number variations (red dots: copy number gain; blue dots: copy number loss) which persisted after the withdrawal of DOXO and were associated with altered cellular morphology and metabolism. The authors also found that these phenotypic and molecular characteristics were associated with chemotherapy-resistant TNBC in clinical samples, thus nominating new targets that may benefit patients who reach this stage of disease. See the Highlight on page 2341 and the article on page 2492 for more information.