Introduction Preclinical models to evaluate therapeutic efficacy in the area of oncology have proven to be a challenge. The standard of preclinical assessment as always been immunosuppressed mice, but that model has not reliably predicted clinical efficacy [1]. Immunocompetent genetically engineered mice with tumor allograft models seem more promising, and yet reporter tags such as GFP and luciferase are targeted by competent immune systems, which may interfere with tumor growth and the response to therapeutics. Here, a collaborative group of researchers has created a reporter-tolerized genetically engineered mouse model, dubbed “Glowing Head” (GH), by targeting a luciferase-GFP reporter into the [...]