Treatment response can be examined using the hematological approach, but the most sensitive method for monitoring CML disease is by using cytogenetics for measuring the frequency of Ph-positive cells and molecular measurement of BCR-ABL transcript levels (Baccarani et al., 2006; Jabbour et al., 2008). The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.