(A) Southern blot of DNA digested with EcoRI and probed with the 0.9-kb fragment of the MLL gene. Control, peripheral lymphocytes. Patient 1 exhibited a rearranged band (arrowhead) with this probe. (B) Northern blot of RNAs from patient 1 and a control leukemic cell line (BALM14) using a 0.5-kb CBP cDNA fragment as a probe. Patient 1 showed an abnormal transcript (arrowhead).