Clinical and Pathological Features of Non-Hodgkin Lymphomas Harboring Concurrent t(14;18) and 8q24 Anomalies
Authors: Alizadeh Ash A. , Anderson Matthew , Kohrt Holbrook E , Shyam Ragini M , Bangs Charles D. , Cherry Athena M , Advani Ranjana , Natkunam Yasodha , Levy Ronald 
Published: October 2019

Abstract 3134

Background:

Concurrent t(14;18) and 8q24 translocations involving BCL2 and MYC in non-Hodgkin lymphomas (NHL) are rare, but are associated with a inferior overall survival (OS) regardless of the presenting or antecedent histological features (Johnson N, et al. Blood 2009). We sought to confirm these observations in an independent cohort of patients with NHL.

Methods:

Metaphase karyotypes and/or fluorescence in-situ hybridization (FISH) were used to identify cases of NHL with cytogenetic abnormalities involving 18q21 and 8q24 (BCL2 and MYC). Clinical and cytogenetic characteristics of these patients were assessed for correlations with pathological and clinical variables including outcome. Histological diagnoses were determined according to the 2008 World Health Organization Classification. Overall survival (OS) was calculated from the date a biopsy demonstrated an abnormality involving MYC to the last follow up date or death, as some cases acquired these lesions during their clonal evolution.

Result:

Among ∼1700 NHL patients diagnosed and/or treated at Stanford University Medical Center on whom cytogenetic studies were routinely performed, we identified 26 patients with evidence for concurrent cytogenetic abnormalities involving BCL2 and MYC. The histological diagnoses at the time of BCL2 and MYC rearrangements were available for 25 of the patients and included follicular lymphoma (FL1-2, n=3; FL3A, n=4), diffuse large B-cell lymphoma (DLBCL, n=2), and B cell lymphoma, unclassifiable, with features intermediate between Burkitt Lymphoma and DLBCL (BCLU, n=16).

Cytogenetic analysis revealed that 13/26 cases with both BCL2 and MYC rearrangements had MYC translocations involving the immunoglobulin (Ig) loci. However, in striking contrast to the <10% prevalence of IgL or IgK partners in NHL harboring Ig-MYC, without Ig-BCL2 rearrangements, 9 of these13 cases (69%) involved IgL t(8;22), and only 4 of these 13 cases (31%) involved IgH t(8;14). 9/26 MYC translocations involved various non-Ig loci (35%). One case (1/26) demonstrated amplification of ?both the BCL2 and the MYC loci by FISH, while one case showed trisomy 8 (1/26). Three cases had FISH analysis only, precluding assessment of the MYC rearrangement partner. No correlation between MYC partner and histology was observed, although this analysis was limited by small sample sizes. Non-FL histology correlated with significantly poorer than expected outcome, with a median OS of 4 months compared to 2 y for FL (p=0.003).

Interestingly, we found cases with low-grade follicular lymphoma (FL1-2) histology which harbored both BCL2 and MYC rearrangements. To better define the frequency of 8q24 anomalies in an unselected cohort of follicular lymphoma cases, FISH for MYC and BCL2 rearrangements was performed on 192 independent low-grade follicular lymphoma (FL1-2) cases. While a subset of these cases (71) showed the expected frequency of BCL2 rearrangements (72%) by FISH, none showed concomitant 8q24 anomalies by FISH, suggesting that routine FISH analysis of low-grade follicular lymphoma for MYC rearrangements would have a low diagnostic yield.

Conclusion:

NHL with rearrangements of both BCL2 and MYC are under-recognized due to lack of routine karyotyping or FISH analysis. Comprehensive analysis of BCL2 and MYC status should be performed on all HGBCL in the new WHO (2008) classification, though the low frequency of these lesions among FL tumors precludes a similar conclusion for low grade NHL.

Disclosures:

No relevant conflicts of interest to declare.