IFNA1 and neoplasm: When the tumor size was ~ 150 mm3, mice were treated with phosphate buffered saline (control), roflumilast (75 μg/kg/day or 5 mg/kg/day, oral administration), and IFN-α (1 × 104 U/mouse/2 days, intraperitoneal injection) either individually or in combination for 28 days before sacrifice.