SLFN11 and cancer: The putative DNA/RNA helicase Schlafen 11 (SLFN11) was independently reported by us (1) and others as the factor that best correlates with the response of cancer cells to DNA-damaging agents (DDAs) with different modes of action, such as topoisomerase I (e.g., topotecan and irinotecan) (2, 3), topoisomerase II inhibitors (e.g., epirubicin), and alkylating agents (e.g., cyclophosphamide or platinum) (4–6).