Southern blot of genomic DNA. DNA was digested with BamHI and the blot was hybridized with pSB. Control lane contains nonleukemic DNA. Lanes 1 through 10 contain DNA from 10 ALL cases. Molecular weight markers are shown on the left and germline TEL (G) is indicated. In this example, cases no. 2, 3, 4, and 9 show rearrangements of TEL.