ETV6 gene rearrangements in patient samples. Southern blot of BamHI-digested genomic DNA hybridized to the 0.9-kb ETV6 cDNA probe. Size standards are in kb. The unique patient numbers are indicated above each lane. Lane 10 contains DNA from a leukemic patient without an ETV6 gene rearrangement. Twenty-kb and 7-kb bands represent germline ETV6 fragments; rearranged fragments representing ETV6 translocations can be identified in all samples except no. 10.