RT-PCR analysis detected the pre-B ALL associated fusion gene TCF3-PBX1 in B-cell line 697 which was absent from both HL cell lines KM-H2 and SUP-HD1, excluding the presence of chromosomal aberration t(1;19)(q23;p13), consistent with the cytogenetic findings (Fig 3A). The gene discussed is PBX1; the disease is acute lymphoblastic leukemia.