Hohensee et al., who showed that PTEN loss has important implications for the metastatic properties of triple-negative breast cancer (TNBC), found several cytokines released into the supernatant when cocultured with astrocytes, particularly in the context of their close involvement with PTEN, and identified granulocyte-macrophage-colony stimulating factor (GM-CSF) (CSF2) as one of them [16]. The gene discussed is CSF2; the disease is triple-negative breast carcinoma.