Evidence shows that there are characteristics exclusive to specific leukemias, including deletion of BTG1 in B-cell leukemia, loss of IKZF1 with monosomy 7 in AML, and deletions involving IGH, TCR, IKZF1, and CDKN2A/B in CML-AP/CP. The gene discussed is CDKN2A; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.