This approach is indeed in agreement with the ‘’3R rules” of animal experimentation (Refine, Reduce, Replace) since, as a non-invasive method, BLI allows to refine the monitoring of tumor growth (as compared to biological monitoring, such as serial blood harvesting for quantification of serum markers: human serum albumin, alpha-fetoprotein, etc.)and to reduce the number of animals required per group, as the same mouse can be monitored several times (as compared to gross examination of tumor volume or weight after liver explant). The gene discussed is AFP; the disease is neoplasm.