The chromosomal region 11q13 is amplified in ∼15% of breast cancers, and Britschgi et al. investigated whether one of the genes in this region, the ANO1 calcium-activated chloride channel, could be a driver oncogene. Overexpression of ANO1 in breast cancer cells without an 11q13 amplification increased proliferation in vitro, whereas ANO1 knockdown in 11q13-amplified cells reduced their proliferation in vitro and decreased their growth as xenografts in mice. Thus, ANO1 might be an oncogenic driver and a putative therapeutic target.