Structure and RT-PCR of H4/PDGFβR fusion.

(A) Structure of the H4/PDGFβR fusion. H4 is fused at amino acid 381 in frame to the PDGFβR gene beginning at amino acid 528. The breakpoint within PDGFβRis identical to that in the TEL/PDGFβR andHIP1/PDGFβR fusions. (B) RT-PCR of the H4/PDGFβRfusion. RNA was extracted from leukemic cells containing the t(5;10)(q33;q22) and from a normal donor and was used as a template for RT-PCR as described in “Materials and methods.” Two sets ofH4/PDGFβR primers, denoted 300F and 720F, were used.H4/PDGFβR-specific transcripts were detected in the leukemic sample but not in the normal control. (C) RT-PCR ofH4(D10S170) was also performed to demonstrateH4(D10S170) expression in both normal and patient samples. As expected, signal was seen in patient, donor, and H4containing plasmid with the use of the 720F primer set, but not in theH4/PDGFβR plasmid.