Palandri et al. [48] measured BCR-ABL levels by real-time PCR in peripheral blood in 130 patients with CML in CP who achieved CCyR with imatinib therapy after IFN-α failure, and they found that patients in unstable MMR, defined by transcript levels sometimes above the MMR (between 0.5 and 1log of the MMR), had a similar risk of losing CCyR as those who had never achieved MMR. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.