P210BCR-ABL is detected in more than 95% of cases with Ph+CML and one third of cases with Ph+ Acute Lymphoblastic Leukemia (Ph+ ALL).5 m-BCR involves intron 1 and joins exon 1 (e1) with a2 resulting in a smaller fusion transcript, e1a2. Here, BCR is linked to chronic myelogenous leukemia, BCR-ABL1 positive.