-Author name in bold denotes the presenting author
-Asterisk * with author name denotes a Non-ASH member
Clinically Relevant Abstract denotes an abstract that is clinically relevant.

PhD Trainee denotes that this is a recommended PHD Trainee Session.

Ticketed Session denotes that this is a ticketed session.

4166 Do Unbalanced MYC Break-Apart FISH Patterns Indicate the Presence of a MYC Rearrangement?

Program: Oral and Poster Abstracts
Session: 621. Lymphomas: Translational—Molecular and Genetic: Poster III
Hematology Disease Topics & Pathways:
Research, Clinical Research
Monday, December 12, 2022, 6:00 PM-8:00 PM

Brett Collinge1*, Susana Ben-Neriah, MSc1*, Laura K Hilton, PhD1*, Waleed Alduaij, MD, PhD1*, Tracy Tucker2*, Graham W Slack, MD, PhD1*, Pedro Farinha, MD, PhD1*, Jeffrey W. Craig, MD, PhD1*, Merrill Boyle1*, Barbara Meissner1*, Kelly Mekwunye1*, Diego Villa, MD1, Alina S. Gerrie, MD, MPH, FRCPC1, Laurie H. Sehn, MD, MPH1, Kerry J. Savage, MD, MSc, FRCPC1, Ryan D. Morin1,3, Andrew J. Mungall, PhD4*, Christian Steidl, MD1 and David W. Scott, PhD, MD, FRACP, FRCPA1

1Centre for Lymphoid Cancer, BC Cancer, Vancouver, BC, Canada
2Cancer Genetics & Genomics Laboratory, BC Cancer, Vancouver, BC, Canada
3Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
4Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC, Canada


High-grade B-cell lymphoma (HGBCL) with MYC and BCL2 and/or BCL6 rearrangement was established as a diagnostic entity in the 2017 WHO-HAEM4 classification. Updated classifications (WHO-HAEM5 and International Consensus Classification [ICC]) have further refined this entity to include only tumors with MYC and BCL2 rearrangement (irrespective of BCL6 status) (HGBCL-BCL2) – albeit with the creation of a new provisional ICC entity for tumors with MYC and BCL6 rearrangement (HGBCL-BCL6). Diagnosis of HGBCL-BCL2 requires fluorescence in situ hybridization (FISH) testing in all tumors with diffuse large B-cell (DLBCL) or high-grade morphology, most commonly performed using FISH break-apart probes (BAPs). Typical MYC BAPs include a red (R) and green (G) probe which hybridize to regions centromeric and telomeric to MYC (8q24.21), respectively. When the MYC locus is intact, 2 fused (F) signals are observed, while separation of a fused signal is indicative of MYC rearrangement (MYC-R) (Figure 1A). Although MYC-R typically produces a balanced BAP pattern (equal R and G signals, e.g. 1F1R1G), a subset of tumors display unbalanced patterns which can be categorized into 3 groups, 1) increased R or G signal (gain-R/G, e.g. 1F2R1G, 1F1R2G), loss of R signal (LR, e.g. 1F1G), or loss of G signal (LG, e.g. 1F1R). As LR and LG patterns indicate loss of genetic material, these patterns have produced uncertainty about whether a MYC-R is present. Understanding the significance of LR and LG patterns is needed as the diagnosis of HGBCL-BCL2 carries important clinical implications, such as these patients commonly receiving intensified treatment.


531 MYC-R tumors with DLBCL or high-grade morphology were identified from the BC Cancer Lymphoid Cancer database. FISH was performed with commercially available BAPs. MYC-R partner and breakpoint location were detected from whole genome or capture sequencing using Manta and GRIDSS2. MYC protein expression was determined by immunohistochemistry (IHC; ≥40% cutoff), and MYC mRNA expression was determined by NanoString.


Among all MYC-R tumors, 69% of MYC BAP patterns were balanced, 17% gain-R/G, 10% LG, and 4% LR. BCL2 and BCL6 FISH was available for 95% (505/531) of biopsies, 60% of which were HGBCL-BCL2, 10% were HGBCL-BCL6, and 30% were MYC single hit.

Among HGBCL-BCL2 tumors, the proportion of each MYC BAP pattern was similar to the proportions observed across all MYC-R tumors, with 65% balanced, 22% gain-R/G, 11% LG, and 3% LR. To assess the significance of the LG and LR patterns in HGBCL-BCL2, MYC protein and MYC mRNA expression levels were compared to HGBCL-BCL2 tumors with balanced patterns, as well as 241 MYC break-apart negative GCB DLBCL. There was no significant difference in MYC mRNA expression levels (LR: p = 0.79; LG: p = 0.30; t-test) and proportions of MYC IHC positivity (LR: p = 1; LG: p = 0.40; Fisher’s exact) in LR or LG groups relative to tumors with a balanced pattern, while both groups had higher MYC mRNA (LR: p = 0.02; LG: p < 0.0001) and IHC positivity (LR: p = 0.0001; LG: < 0.0001) compared to GCB DLBCL.

Sequencing was available for 44% (132/302) of HGBCL-BCL2 tumors. A translocation partner was detected for 88% (78/88) of tumors with a balanced pattern, compared to 64% (9/14) of tumors with an LG pattern (p = 0.66; Fisher’s exact), and 100% (5/5) with an LR pattern (Figure 1A). Among tumors with an identified translocation partner, the breakpoint was centromeric to MYC in 80% (4/5) of tumors with an LR pattern, while 100% (9/9) of tumors with an LG pattern had a breakpoint telomeric to MYC (Figure 1A and B). For a centromeric break, the resulting rearrangement places MYC on the derivative chromosome containing the G signal, while for a telomeric break, MYC is placed on the derivative chromosome containing the R signal (Figure 1B). As such, the MYC gene was preserved in 93% (13/14) of tumors with an LR or LG pattern.


An unbalanced LR or LG MYC FISH pattern was observed in 14% of HGBCL-BCL2. These tumors displayed similar MYC protein and MYC mRNA expression levels as HGBCL-BCL2 tumors with balanced MYC FISH patterns. While detection of a translocation in sequencing data can be limited by factors such as poor biopsy quality, a translocation partner was identified for the majority of tumors with LR and LG patterns, with all but 1 translocation preserving the MYC gene. These results support that LR and LG patterns should be interpreted as a positive MYC FISH result.

Disclosures: Craig: BeiGene: Honoraria; Bayer: Consultancy. Villa: Roche, AstraZeneca, Abbvie, Janssen, Kite/Gilead, BMS/Celgene, BeiGene, Kyowa Kirin: Consultancy, Honoraria; AstraZeneca, Roche: Research Funding. Gerrie: AbbVie: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Sandoz: Honoraria. Sehn: AbbVie, Acerta, Amgen, Apobiologix, AstraZeneca, BMS/Celgene, Gilead, Incyte, Janssen, Kite, Karyopharm, Lundbeck, Merck, Morphosys, Sandoz, Seattle Genetics, Servier, Takeda, TG Therapeutics, Verastem: Honoraria; Chugai: Consultancy, Honoraria; AbbVie, Acerta, Amgen, Apobiologix, AstraZeneca, BMS/Celgene, Debiopharm, Genmab, Gilead, Incyte, Janssen, Kite, Karyopharm, Lundbeck, Merck, Morphosys, Novartis, Sandoz, Seattle Genetics, Servier, Takeda, TG Therapeutics, Verastem: Consultancy; Teva, Roche/Genentech: Consultancy, Honoraria, Research Funding. Savage: Beigene and Regeneron: Membership on an entity's Board of Directors or advisory committees; BMS, Janssen, Kyowa, Merck, Novartis, and Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Steidl: AbbVie: Consultancy; Bayer: Consultancy; Bristol-Myers Squibb: Consultancy; Curis Inc: Consultancy; Epizyme: Research Funding; Roche: Consultancy; Seattle Genetics: Consultancy; Trillium Therapeutics: Research Funding. Scott: Janssen: Consultancy, Research Funding; Roche: Research Funding; NanoString: Patents & Royalties; Incyte: Consultancy; AstraZeneca: Consultancy, Honoraria; Abbvie: Consultancy.

*signifies non-member of ASH