Identification of a novel OBFC2A/RARA fusion gene by FISH, array CGH, RT-PCR and direct sequencing. (A) Representative partial karyogram shows der(2)t(2;17)(q32;q21). FISH with the RARA break-apart probe reveals a 3′ RARA green signal on der(2), indicated by arrows. (B) Array CGH demonstrates that the breakpoints corresponding to a loss in 2q32.3-qter and a gain in 17q21.2-qter map to the OBFC2A and RARA genes. (C) The OBFC2A/RARA fusion transcript is amplified with an internal control (β-actin) by RT-PCR. (D) Partial nucleotide sequences surrounding the OBF2CA/RARA fusion region reveal the junction of OBFC2A exon 5 and RARA exon 3. (E) Schematic diagram represents the OBFC2A, RARA, and OBF2CA/RARA fusion proteins, including the activation function-1 (AF-1), DNA-binding domain (DBD), hinge, and ligand-binding domain (LBD).