Would you start TKI therapy in a patient with new diagnosis of T-ALL without BCR-ABL gene rearrangement on FISH but found to have very low level p190 transcript on RT-PCR?  

I would not. I don't necessarily have any evidence to support this, so this is simply an opinion. I have seen this a couple of times in my clinical practice. If there is truly BCR-ABL present in this patient's leukemia, the level of it would have to be extremely low to only be detectable at this re...