According to the NCCN® clinical practice guidelines on CML [9], the most important goal of first-line TKI therapy is to prevent disease progression through regular surveillance (every 3–6 months), following achievement of the treatment milestone of BCR::ABL1(IS) ≤ 1% at 12 months,. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.