Скачать или смотреть MYC Rearrangements in Diffuse Large B-Cell Lymphoma: Impact and Implications for Diagnostic Testing

This podcast summarizes the findings of the Lunenburg Lymphoma Biomarker Consortium systematic evaluation of MYC rearrangements in DLBCL, and discusses the prognostic impact of MYC, BCL2 and BCL6 rearrangements, and implications for FISH testing in newly diagnosed DLBCL.


 


TRANSCRIPT


This JCO Podcast provides observations and commentary on the JCO article “Prognostic Significance of MYC Rearrangement and Translocation Partner in Diffuse Large B-Cell Lymphoma - A Study by the Lunenburg Lymphoma Biomarker Consortium” by Rosenwald et al. My name is Jeremy Abramson, and I am an attending physician at the Massachusetts General Hospital and an Associate Professor of Medicine at Harvard Medical School. My oncologic specialty is lymphoma.


MYC rearrangements occur in approximately 10% of diffuse large B-cell lymphomas and have been associated with a worse prognosis.  When the MYC translocation occurs in concert with translocations of BCL2, BCL6, or both, initial series have suggested particularly poor outcomes with few patients achieving long term survival with conventional therapies.  This entity has been classified in the current WHO classification as high-grade B-cell lymphoma with rearrangements of MYC and BCL2 and/or BCL6 and is more conventionally known as double (or triple) hit lymphoma.  Though initial series painted a grim prognosis for these patients, more recent larger series have suggested that approximately 40% of double hit lymphoma patients may be cured, and that outcomes may be improved with more intensive regimens such as dose-adjusted EPOCH-R.  Most of these published series to date, however, continue to be limited by significant selection bias whereby cases with the most aggressive clinical or histopathologic features are likelier to be tested for MYC translocations, thus potentially excluding more prognostically favorable patients.  The small size of series to date has also made it difficult to assess more granular questions in MYC translocated diffuse large B cell lymphoma, hereafter referred to as DLBCL, such as the prognostic impact of MYC translocations when occurring without other translocations, the impact of translocation partner with MYC (Ig or non-Ig gene locus) in double hit lymphoma, and the significance of MYC/BCL6 double hit lymphomas which are far less common than MYC and BCL2.  Another practical question is who should we be testing for MYC translocations in the first place? Do we need to test every new case of DLBCL?  Or should we routinely test only an enriched population, such as those with MYC protein expression by immunohistochemistry, or GCB-like DLBCLs, which include the majority of double hit lymphomas?


In the article that accompanies this podcast, the Lunenberg Lymphoma Biomarker Consortium  presents the single largest and most systematic analysis to date of MYC translocations in DLBCL, and sheds significant light on many of the most outstanding questions in this population. The Consortium studied over 2000 cases of DLBCL with available tissue and clinical data, drawn from large prospective cooperative group studies as well as population-based registries in Canada, the United Kingdom and the United States. The median age of the cohort was 66 years, and the median follow up was mature at greater than 6 years. All patients were treated with R-CHOP or R-CHOP-like therapy.  MYC rearrangements were found in 11% of patients. One third of these occurred as a sole rearrangement, 39% in concert with a BCL2 rearrangement, 15% with a BCL6 rearrangement, and 12% with both (i.e. triple hit lymphoma).


Patients with MYC rearrangements had higher risk features by the IPI score than the entire DLBCL population, and patients with double/triple hit lymphoma had higher clinical risk factors than patients with MYC rearrangements alone. Patients with double or triple hit lymphoma had a significantly inferior outcome in terms of both progression free and overall survival compared to the overall DLBCL cohort, while no negative prognostic impact was conferred by a MYC translocation alone. Notably, the prognostic impact was only observed in the first 2 years from diagnosis.  They also compared the 31 MYC/BCL6 double hit patients with 82 MYC/BCL2 double hits, and found similar outcomes in the groups, validating that MYC/BCL6 double hit lymphomas should be considered high risk along with their BCL2 translocated counterparts. Prognosis for triple hit lymphoma was no worse than double hit lymphoma.  Perhaps most striking, however, was how well double and triple hit lymphoma patients did when compared to previously published retrospective studies. In this comprehensive evaluation by the Consortium, approximately 60% of double and triple hit lymphoma patients remained progression free beyond 5 years, and two thirds remained alive.  These remarkable data suggest that the majority of double and triple hit lymphomas identified by broad screening of the DLBCL population may be cured with ...