High Levels of Nuclear MYC Protein Predict the Presence of MYC Rearrangement in Diffuse Large B-cell Lymphoma

Abstract

Determining the presence of MYC gene rearrangements is becoming an increasingly important part of the diagnostic workup in aggressive lymphoma. Cytogenetic MYC alterations aid in differentiating diffuse large B-cell lymphoma (DLBCL) from Burkitt lymphoma. In addition, MYC aberrations are associated with poor prognosis in DLBCL. Fluorescence in situ hybridization and karyotyping are standard tests for detecting MYC aberrations, but these techniques are laborious and expensive. Here, we studied MYC status of 219 DLBCLs and Burkitt lymphomas using fluorescence in situ hybridization, immunohistochemistry, and quantitative real-time polymerase chain reaction (QRT-PCR). Overall, 15% of the cases had an MYC break. QRT-PCR analysis of MYC expression showed that 72% of DLBCLs with an MYC break had aberrantly high or low levels of MYC transcript. Excluding the cases with aberrantly low MYC expression, we found a significant positive correlation between levels of MYC transcripts and MYC tumor cells; however, QRT-PCR is not readily applicable as a screening tool. Immunohistochemically, all tumors showed a nuclear staining pattern that was simple to evaluate. The percentage of MYC lymphoma cells correlated closely with MYC rearrangement status. In all, 93% of cases with an MYC break had ≥80% MYC cells, in contrast to 3% of nonrearranged cases (P<0.0001). Receiver operating characteristic curve analysis showed ≥70% MYC tumor cells to be the optimal cutoff (sensitivity=100%, specificity=93%). Area under the receiver operating characteristic curve was 0.992, indicating that immunostaining for Myc protein is an excellent screening test to predict whether an MYC rearrangement is present.

Clinical features, tumor biology, and prognosis associated with MYC rearrangement and Myc overexpression in diffuse large B-cell lymphoma patients treated with rituximab-CHOP

“…To reduce the difference in Myc expression levels as a causing factor for the differential prognostic effect and tumor biology between MYC translocation and Myc overexpression activated by other mechanisms, the cutoff for Myc high was set at ≥ 70% in this study, which is the optimal cutoff for predicting MYC translocation according to previous studies. 6,7,31 Using this cutoff, the frequency MYC-associated biology and prognosis in DLBCL of Myc overexpression was 32.7% in overall DLBCL patients (close to the frequencies by other independent studies 13,22,23 ), 73% in MYC-R + GCB-DLBCL, and 54% in MYC-R + ABC-DLBCL (lower than the 93% in Green et al 6 and 85% in Horn et al 10 ). Tables 6-7 summarize the results of published MYC studies including ours.…”

“…3 The chromosomal rearrangement or translocation involving MYC and other genes (most commonly the immunoglobulin heavy-chain gene (IGH) locus) leads to Myc overexpression and occurs in~10% of diffuse large B-cell lymphomas (DLBCLs). [4][5][6][7][8] DLBCL is the most common type of non-Hodgkin's lymphoma, and among MYC-rearranged aggressive lymphomas, DLBCL is the entity that clinicians most commonly encounter. 9,10 Several studies have reported that MYC translocations independently predicted significantly poor survival in DLBCL patients.…”

A diffúz nagy B-sejtes lymphoma modern szemlélete és kezelése

“…Még érdekesebb, ha adataikat a GCB-és ABC-csoportokban külön vizsgálták, mivel mindkét csoportban a kettős negatív esetek 5 éves túlélése 100%, míg a kettős pozitív esetek esetén a GCB-csoportban és az ABC-csoportban is 45% körüli túlélés igazolható [13]. A fentieken kívül még több szerző publikálta adatait a double hit lymphomák kezelésével kapcsolatban és megállapítható, hogy R-CHOP-vázas kezelés alkalmazása esetén a PFS és OS rosszabb a double hit esetekben [14]. Ugyanakkor R-DA-EPOCH (dózisadaptált rituximab, etopozid, ciklofoszfamid, vincristin, adriablastin, prednisolon) alkalmazása esetén a hátrány lecsökken nem szignifikáns mértékre [15].…”

Definition of MYC genetic heteroclonality in diffuse large B-cell lymphoma with 8q24 rearrangement and its impact on protein expression

“…Using this antibody, Burkitt lymphoma with MYC rearrangement were found to show intense positive staining for MYC protein in the vast majority of the cells, supporting the existence of a strong correlation between gene and protein status. [6][7] In contrast, in MYC rearranged diffuse large B-cell lymphoma, the association between rearrangement and protein expression is less clear, as approximately one-third of cases with this rearrangement show protein staining in o 40% of the tumor cells. 5,[8][9][10][11][12] Conventional and molecular cytogenetic studies of diffuse large B-cell lymphoma have described cases with MYC rearrangement that are characterized by complex karyotypes, revealing the presence of different populations of cells with loss/extra copies of derivatives of the MYC rearrangement and/or extra copies of chromosome 8.…”

“…Expression in 440% of tumor cells was used as a cutoff to classify a case as MYC positive, as reported in the literature. [7][8][9] Fluorescence In Situ Hybridization FISH was performed on 3-to 4-μm-thick formalin-fixed paraffin-embedded tissues sections following current recommendations, as previously described. 29,30 The commercially available MYC split signal probe from Dako was applied to all cases (MYC FISH DNA Probe, Split Signal, Dako).…”