However, when examining the division efficiency, that is the ability to divide in a tumor once colonization occurred, osteosarcoma and neuroblastoma had the highest division efficiency.14 Furthermore, in vivo experimentation has demonstrated that orally administered Salmonella-IL2 can robustly colonize a variety of tumor types.9,15,16 Because Salmonella can colonize solid tumors, we maintain that Salmonella-IL2 can act as a “smart bomb” by invading and locally releasing IL-2 into the tumor microenvironment and avoid any systemic toxicity from the IL-2. The gene discussed is IL2; the disease is neuroblastoma.