The New York Times has published an intriguing profile of Champions Oncology, a company using so-called mouse 'avatars' to replicate the immune systems of cancer patients. Researchers at the New Jersey-based organization take tumors that have been freshly extracted from patients and slice them up for insertion into specially-bred mice, letting the cells grow inside the animals until they have a sufficient number to conduct a study. They then test various cocktails of drugs on the mice, using the results to determine which could work best on the human patient. The treatment isn't cheap — a study of four different drugs for a 9-year-old Ewing's sarcoma sufferer earlier this year cost $25,500 — and there is, as yet, no cast-iron guarantee that the technique actually works. Still, for those able to pay, it provides an extra glimmer of hope. Head over to The New York Times to find out more about the process, and how it's being used to treat other diseases as well.