Tetracycline in mice and tyrosine kinease drugs in humans can inhibit generation of leukemia, but they don't eliminate BCR-ABL1. New tyrosine kinease inhibitors are now being tested on humans, but it remains to be proved that they can do the job alone. More effective treatments will probably involve combinations of the inhibitors with chemotherapy drugs, radiation, and bone marrow transplants. The Harvard mice offer unique advantages for doing these tests. Huettner describes a scenario wherein a laboratory begins testing a therapy when a power failure or other emergency occurs.
Researchers can simply give tetracycline to their subjects to arrest progression of the cancer.
Working with reversible mice has also led to greater understanding of how cancer arises and maintains itself. For many years, cancer in general was believed to arise through a complex multistep process that involves several genetic abnormalities. Now we know that the answer is yes for mice, and it appears that the same can be said for humans. Therefore, you would need to get rid of only one gene to effect a lasting cure for some leukemias and any other cancers that arise in this way. Huettner's goal is to engineer mice with other diseases that closely mimic human maladies.