Amplification of genomic breakpoint on derivative chromosome 2. Genomic DNA was subjected to standard and nested amplification, followed by product separation on a 1% agarose gel. Ethidium bromide staining of standard DNA-PCR products (A) and of the nested DNA-PCR products (D). Lanes 1 through 11, cases 1 through 11; lane 12, t(2;5)⁺ SU-DHL-1 cell line; lane M, molecular weight marker 1-kb DNA ladder (GIBCO-BRL). The gels were transferred to a nylon membrane and hybridized either with the ALK-2P (radioautographies B and E) or the NPM-2P (radioautographies C and F). The sizes are indicated in bases.