Aneuploidy-driven genome instability triggers resistance to chemotherapy

Mitotic errors lead to aneuploidy, a condition of karyotype imbalance, frequently found in cancer cells. Alterations in chromosome copy number induce a wide variety of cellular stresses, including genome instability. Here, we show that cancer cells might exploit aneuploidy-induced genome instability to survive under conditions of selective pressure, such as chemotherapy. Resistance to chemotherapeutic drugs was dictated by the acquisition of recurrent karyotypes, indicating that gene dosage, together with mutational burden, might play a role in driving chemoresistance. Thus, our study establishes a causal link between aneuploidy-driven genome instability and chemoresistance and might explain why some chemotherapies fail to succeed.