IFNB1 and neoplasm: To test if the p19Arf/IFNβ + Dox treatment results in superior immunogenicity of the treated cells, we employed a cancer immunotherapy model in which MCA or B16 cells were treated ex vivo with p19Arf/IFNβ, Dox or their combination, and before the start of the cell death process (i.e., not detectable by PI staining), cells were injected (s.c) to die within the host and function as a cancer vaccine immunogen against a previously established growing tumor, termed as challenge tumor.