To determine whether this combination could effectively arrest cancer progression in vivo, we treated mice with implanted pancreatic cancer with the clinically approved TOP1 poison irinotecan (15 mg/kg, three times weekly, every second week), the BRD4 inhibitor JQ1 (50 mg/kg, daily), or both drugs in combination by intraperitoneal (i.p.)injection. Here, BRD4 is linked to cancer.