U‐2973, a novel B‐cell line established from a patient with a mature B‐cell leukemia displaying concurrent t(14;18) and MYC translocation to a non‐IG gene partner

Abstract

B-cell lymphomas/leukemias with simultaneous t(14;18)(q32;q21) and MYC rearrangements have recently been shown to constitute a separate diagnostic entity, presenting with a rapid clinical course and a very poor prognosis. We describe the establishment of an Epstein-Barr virus negative cell line, designated U-2973, from a male patient with a de novo aggressive B-cell lymphoma/leukemia and very high peripheral blast cell count. Flow cytometry of bone marrow cells and U-2973 displayed a mature B-cell phenotype, and immunostaining showed expression of MYC and BCL2. IG gene rearrangement data were consistent with a lymphoid neoplasm of germinal centre derivation. Cytogenetic studies using conventional G-banding, fluorescent in situ hybridization, spectral karyotyping and single nucleotide polymorphism array demonstrated a complex karyotype with both a t(14;18) and double translocations between MYC and a non-IG gene partner located at chromosome 12p12.1.

Sequence based analysis of U-2973, a cell line established from a double-hit B-cell lymphoma with concurrent MYC and BCL2 rearrangements

“…One breakpoint lies within the IGH gene on chr14 and the other roughly 20kbp upstream of BCL2 on chr18. This is consistent with previous observations of IGH-BCL2 fusions in 96% of the blood sample [7] and in the FISH-analysis on the cell line (Additional file 1: Figure S1C). Furthermore, the breakpoint between chr14 and chr18 is interspersed with a 31 bp sequence which has no homology to the reference (hg18) genome.…”

“…[4-6]) and have attracted research interest due to their unique cytogenetic features and relatively poor prognosis. Recently a stable B-cell line (U-2973) was established [7] from a DH lymphoma patient. This derived cell line does not necessarily represent the full clonality or tumorigenesis of the patient, but retains the main translocations initially identified in the patient.…”

“…The M-FISH and karyotyping were performed as the DNA was extracted for the sequence analysis to verify the karyotype reported earlier (Additional file 1: Figure S1A and Additional file 2: Figure S2A) [7]. FISH hybridizations using gene specific probes ( MYC and IGH-BCL 2) and whole chromosome paint hybridizations (WCP8 and WCP12; WCP 17 and WCP20) were performed to confirm the findings of the M-FISH, on cells from an independent culture.…”

“…In the previous analysis [7], it was established that the biallelic t(8;12) translocation involved MYC on chr8 and potentially the LRMP gene on chr12, but more detailed positions could not be determined. In this study, the biallelic translocation could be more accurately determined and the positions of the breakpoints suggest that LRMP may have been lost on the two derivative chromosomes 12.…”

“…The U-2973 cell line was established from a biopsy with the informed consent of the patient and approved by the local ethical review board (Uppsala 00–275) as described in the original study [7]. DNA was prepared and sequenced on the ABI SOLiD parallel sequencing system according to the manufacturer's instructions.…”