More than 95% of Ph+ CML patients express the typical e13a2 (b2a2) and/or e14a2 (b3a2) BCR-ABL1 transcripts located within the major breakpoint cluster region (M-BCR) associated with a p210 fusion protein. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.