Histone acetylation as a therapy target in B-cell malignancies

Multi-Cancer Early Detection Test Is Sensitive and Accurate in Detecting Shared DNA Methylation Signal in a Variety of Lymphoid and Plasma Cell Neoplasms

Advances in therapy in recent years have led investigators to challenge the dogma that multiple myeloma (MM) is incurable. We assessed overall (OS) and progression-free survival (PFS) of young patients ( ≤ 50 years) with MM and compared outcomes with follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), and Hodgkin lymphoma (HL). All patients ≤ 50 years with newly diagnosed MM (n = 212), FL (n = 168), DLBCL (n = 195), and HL (n = 233) between 1 January 2005 and 31 December 2015 were included. Observed vs. expected survival was summarized by standardized mortality ratios (SMR). Compared to the background US population, excess mortality risk was seen at diagnosis in all four cancers, SMR 19.5 (15.2–24.5) in MM, 4.2 (2.3–7.2) in FL, 13.0 (9.2–18.4) in DLBCL, and 5.2 (2.6–9.3) in HL. We reasoned that cure would most likely occur in the first 3 years after diagnosis and be reflected by an overall survival probability similar to the background population. From the 36-month landmark, excess mortality risk was seen in MM (SMR 20.7 [14.7–28.3]) and FL (SMR 3.8 [1.5–7.8]), but not with DLBCL (SMR 3.1 [0.8–8.0]) or HL (SMR 0.9 [0.0–5.1]). MM patients have 20-fold excess mortality risk compared to the background population at diagnosis and at 3 years after diagnosis, suggesting that MM remains an incurable cancer.

Tumors with an excessive amount of stroma have been recognized by pathologists for many decades, for example scirrhous carcinomas of the stomach or breast, fi brolamellar hepatocellular carcinoma, Hodgkin lymphoma (HL) or T-cell/histiocyte-rich large B-cell lymphoma, to name a few. Th e stroma in these tumors is part of their defi nition. Notwithstanding, virtually all tumors contain stromal cells, albeit to varying degrees [1]. Of interest, the nature of the stromal component has also been shown to correlate with prognosis or therapy outcome [1]. In vitro testing has further indicated that stromal cells are active determinants of tumor cell proliferation, diff erentiation and apoptosis [2]. Th erefore, the tumor stroma deservedly has become a major focus of study. Understanding tumor stroma may allow us to devise therapy to counteract its growth-stimulating or stimulate its growthinhibiting characteristics. Recently, novel insights have been gained into the potential role of the stroma in major lymphoma types, especially follicular lymphoma (FL), HL and diff use large B-cell lymphoma (DLBCL). Th e components of the immunological response in FL are clearly associated with survival. Using gene expression analysis, Dave et al . could discern diff erent types of immune response signatures, named immune-response 1 and immune-response 2, respectively [3]. Th e immuneresponse 1 gene signature was shown to be derived from infi ltrating T-cells and to a lesser degree from monocytes, whereas immune-response 2 genes were mainly derived from monocytic cells. Of interest, immune-response 1 genes were correlated with improved survival, whereas immuneresponse 2 genes were correlated with unfavorable survival [3]. However, subsequent studies using tissue microarrays and immunohistochemical methods for characterization of the stromal components have yielded confl icting results with regard to the prognostic impact of infi ltrating cells [4]. Th e latter may partly be due to diff erences in treatment of the patients in the studies [5]. Multiple studies have also indicated that the stromal response in HL is associated with survival diff erences [6]. More specifi cally, gene expression studies indicated that an increased number of infi ltrating macrophages is associated with a less favorable outcome, as demonstrated for FL [7]. Other studies using immunohistochemistry on tissue sections have yielded similar fi ndings [6]. Equally, a stromal gene expression signature can invariably be detected in DLBCL [8 – 10]. DLBCL is molecularly heterogeneous, and can in more than 50% of cases be cured with an anthracycline-based chemotherapy combined with rituximab immunotherapy. Th e addition of immunotherapy improved the survival of patients compared with chemotherapy alone [11]. Th is is true for the two major molecular subtypes of the disease, germinal center B-cell-like and activated B-cell-like [10,12]. However, there still remains an important proportion of patients who cannot be cured with this therapy. Of interest, the stromal component in DLBCL as well as the expression of surface molecules that are important for interaction with stromal cells such as human leukocyte antigen class I and II molecules have proved to be important determinants of survival, irrespective of the molecular subtype [8]. Lenz et al . have shown by gene expression analysis of DLBCL, including expression analysis of fl ow-sorted samples, that especially two types of stromal response determine outcome, called stromal-1 and stromal-2, which result in an improved or worse survival, respectively, for patients treated with immunochemotherapy [10]. Th e stromal-1 response involves connective tissue growth factor and components of the extracellular matrix such as fi bronectin, osteonectin, collagen and laminin isoforms, as well as enzymatic modifi ers of collagen and extracellular matrix components. Th e stromal-2 response consists of genes that encode key regulators of angiogenesis, such as, for example, vascular endothelial growth factor, as well as endothelial cell markers such as CD31, and adipocyte markers. Of interest, the stromal-1 response is mediated by infi ltrating monocyte-derived cells. Th e favorable prognostic impact of monocyte-derived cells suggest another role of these cells in DLBCL compared with FL and HL. In this issue of Leukemia and Lymphoma , Rydstr o m et al . show that expression of CD40 by diff use large B-cell lymphoma, a putative marker for favorable prognosis in DLBCL, is associated with the up-regulation of genes coding for extracellular matrix components as well as proteolytic enzymes, thus approaching the stromal-1 signature [13]. Whether activation through CD40 expressed by diff use large L eu k L ym ph om a D ow nl oa de d fr om in fo rm ah ea lth ca re .c om b y 61 .2 21 .3 3. 39 o n 05 /2 0/ 14

Identification of Genes Frequently Mutated In FL and DLBCL with Transcriptome, Genome and Exome Sequencing

B- Cell Maturation Antigen Is Exclusively Expressed in a Wide Range of B-Cell and Plasma Cell Neoplasm and in a Potential Therapeutic Target for Bcma Directed Therapies

Optimisation of metabolic criteria in the prognostic assessment in patients with lymphoma. A multicentre study.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL), representing around 30% to 40% of all newly diagnosed lymphomas 1. DLBCL is clinically, morphologically and biologically a heterogeneous disease reflected in the highly variable clinical course. The 2008 World Health Organization (WHO) classification of lymphoid malignancies recognizes within the group of DLBCL, not otherwise specified (NOS) several subtypes characterized by unique clinical and pathological features including primary DLBCL of the central nervous system (CNS), primary cutaneous DLBCL, leg type, T-cell histiocyte-rich large cell lymphoma and EBV positive DLBCL of the elderly (Table 1). Nevertheless, most cases of DLBCL fall into the ‘NOS’ category. In the last 15 years our understanding of the genetic changes and biology of DLBCL has increased tremendously 2. Gene expression profiling (GEP) studies have revealed that DLBCL comprises several molecular subgroups that reflect either the stage in B cell development from which the disease originates or the activity of different biological programs 3, 4. The standard initial treatment for DLBCL is combined immunochemotherapy with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) 5. While durable remissions can be achieved in the majority of cases with this combined regimen, over 30% of patients will not respond or will relapse with resistant disease. A possible explanation for such differences in therapeutic success is the considerable biological heterogeneity of DLBCL. Therefore, there is an ongoing effort to tailor therapy based on specific subtypes of DLBCL, and to identify prognostic markers like BCL2 and MYC. The diagnosis of DLBCL needs to integrate, in addition to classic morphology and immunophenotype, all the new genetic and molecular diagnostic tools. This report attempts to review distinctive pathological characteristics of DLBCL and their clinical significance. DLBCL is characterized by monoclonal rearrangement of immunoglobulin heavy (IGH) and light chain (IGκ-IGλ) genes. Analogous to most B-NHL, DLBCL derives from a mature B cell that has experienced the germinal center (GC) reaction. Based on GEP studies DLBCLs have been divided into two main subgroups based on the putative cells of origin 3, 4. GC B cell-like (GCB)-DLBCL (50% cases) exhibits a transcriptional profile that resembles that of GC B-cell with expression of genes normally detected in GC B-cells such as CD10 and the transcriptional repressor BCL6 and harboring highly mutated immunoglobulin genes with ongoing somatic hypermutations (SHM). Activated B cell-like (ABC)-DLBCL shows several features of B cell receptor (BCR) activated B-cells at a plasmablastic stage, just prior to exit the GC with up-regulation of genes required for plasma cell differentiation (IRF4/MUM1) (Figure 1). These tumors downregulate the GC-specific program, activating at the same time, the NF-κB and BCR signaling pathways 2. Consistent with their late GC origin, these tumors do not show evidence of ongoing SHM. Because not all cases of DLBCL can be characterized as GCB or ABC, a less well-characterized group comprising about 15% of the cases remain unclassifiable. Within the group of mature B cell NHL, DLBCL shows the highest degree of genomic complexity including point mutations and copy number aberrations, and less frequently chromosomal translocations and gene amplification 2. Although some of these lesions might be observed in both GCB and ABC subtypes of DLBCL, most of them are preferentially associated with one or the other subtype of DLBCL, suggesting their potential role for diagnostic, prognostic and therapeutic stratification (Figure 2). The frequent mutations found in DLBCL are thought to be the result of an aberrant function of the physiologic SHM mechanism. Accordingly, mutations in CREBBP/EP300 and MLL2 are preferentially seen in GCB-subtype. EZH2 is required for GC formation and mutations in this gene are restricted to GCB-DLBCL. Translocations resulting in deregulated BCL2 and MYC are almost restricted to GCB-DLBCL. Around 30–40% of GCB-DLBCL carry the t(14;18) translocation, whereas MYC translocations have been identified in 5–15% of DLBCL 6. In contrast, translocations involving the BCL6 locus are present in 35% of DLBCL cases, being more frequent in ABC-DLBCL (25%). Another major transformation mechanism that impairs plasma cell differentiation are mutations and deletions in PRDM1/BLIMP1 identified in 25% of ABC-DLBCL. Constitutive activation of the NF-κB transcription factor complex represents the hallmark of ABC-DLBCL 2. The underlying causes of NF-κB signaling pathway activation are diverse and include gain-of-function mutations in signal transduction components of the BCR (CD79a and CARD11) and toll-like receptor (MYD88) signaling pathways. Loss-of-function mutation and/or deletions in the NF-κB negative regulator TNFAIP3/A20 have been reported in up to 30% of ABC-DLBCL. The diagnosis of DLBCL is usually not difficult. Lymph nodes demonstrate a diffuse proliferation of large lymphoid cells that have totally or partially effaced architecture. Cytological, DLBCL can be centroblastic, immunoblastic or anaplastic in appearance 1. Centroblastic morphology is the most common variant composed of medium to large cells with round to oval vesicular nuclei and fine chromatin with two to four nuclear membrane-bound nucleoli. There is moderate amphophilic to basophilic cytoplasm. In the immunoblastic variant greater than 90% of the cells have an immunoblastic appearance with a large centrally located nucleolus and basophilic or amphophilic cytoplasm. This variant has been associated with the non-germinal center type derivation, an adverse prognosis 4 and recently as a major reservoir for MYC-IGH translocations. In most cases, however; the tumors show an admixture of centroblasts and immunoblasts. The distinction of the immunoblastic variant from the centroblastic variant is not always straightforward and has generally met poor intraobserver and interobserver reproducibility. The anaplastic variant is rather rare and is characterized by large cells with bizarre pleomorphic nuclei. These cells may resemble Hodgkin or RS cells and may show sinusoidal and/or cohesive growth pattern and even mimic undifferentiated carcinoma. The anaplastic morphology is independent of ALK expression in B-cell lymphomas. Other rare morphologic variants exist including the signet ring cell, microvillous and spindle cell variants. The neoplastic cells characteristically express pan B-cell markers including CD19, CD20, CD22, PAX5 and CD79a. Surface and/or cytoplasmic immunoglobulin (IgM > IgG > IgA) can be demonstrated in 50–75% of the cases. Other markers commonly used in the characterization of DLBCL include CD10, BCL6, BCL2 and IRF4/MUM1 1. Aberrant phenotypes are not uncommon in DLBCL and may be responsible for confusion in the diagnosis. Lack of one or more B-cell markers may occur. In 10% of the cases the tumor cells express CD5. This CD5 positive DLBCL usually represent de novo cases, and only rarely are transformed CLL cases. Expression of CD5 is associated with worse prognosis even in the rituximab era. Aberrant expression of cytoplasmic CD3 has been also documented mainly in extranodal DLBCL without the expression of other T-cell markers. DLBCL with cyclin D1 expression lack the characteristic t(11;14) translocation of MCL, have a centroblastic morphology and a post-germinal center phenotype with positivity for IRF4/MUM1. These cases should be distinguished from MCL with blastic or pleomorphic morphology. In situ hybridization for EBERs should be performed in cases with geographic necrosis and/or Reed–Stenberg-like cells to exclude the possibility of an EBV+DLBCL of the elderly. Because of the prognostic value of cell of origin and the increasing effort to tailor therapy based on molecular characteristics of DLBCL, a reliable method to identify GCB and non-GCB subtypes is needed. GEP, which is considered the gold standard to assign the molecular subtypes, is not routinely available and is not cost effective in routine diagnosis. Several studies have attempted to recapitulate the molecular subgroups (GCB vs. non-GCB) using a limited panel of antibodies available in most pathology laboratories (Figure 1). The Hans algorithm has been the most widely used in clinical trials. In this classifier three antibodies are used CD10, BCL6 and IRF4/MUM1. According to this algorithm DLBCL with CD10 expression in more than 30% cells belong to the GCB group. Cases that are CD10 negative, BCL6 positive but IRF4/MUM1 negative are also GCB subtype. Cases that are IRF4/MUM1 positive with or without expression of BCL6 are assigned to the non-GCB subtype. There have been other algorithms attempting to improve the Hans classifier. These include the use of FOXP1 and GCET1 by Choi et al., and the use of LMO2 by Natkunam et al. One study comparing different algorithms showed an 87% concordance with GEP for the Choi method and 86% for Hans scheme 7. In this same study, the Tally algorithm based on FOXP1, GCET1, CD10, IRF4/MUM1 and LMO2 antibodies was demonstrated to be the most robust. The use of BCL6 was excluded from the analysis because it was considered a problematic, poorly reproducible stain. Nevertheless, in our experience BCL6 is reliable and helpful in the routine diagnosis. Accordingly, in the report from the international DLBCL rituximab-CHOP consortium program study, an algorithm based on expression of CD10, FOXP1 and BCL6 was used, which had a 92.6% concordance with GEP 8. Although most studies find that immunohistochemical algorithms correlate with prognosis in DLBCL, everybody agrees that these algorithms are an imperfect substitution for GEP. The improvement of molecular techniques is making possible to use paraffin-embedded material with results comparable to fresh-frozen material. The recent development of a 20-gene assay using NanoString technology in paraffin-embedded tissue is a promising methodology with potential to be used as a routine method for determining cell of origin in DLBCL 9. Translocations involving the MYC oncogene are the molecular hallmark of Burkitt lymphoma (BL). Most cases involve the IGH@ gene on chromosome 14. Less commonly, the light chain genes on chromosome 2 and 22 are involved in the translocation. These translocations in BL are characteristically the sole chromosomal aberration identified 10, 11. Approximately 5 to 15% of DLBCL cases have been reported to carry MYC translocations, whereas 19–38% of cases show MYC low copy number gains 6. Most MYC rearranged DLBCL cases fall into the GCB subtype 10, 12. In contrast to BL, MYC rearrangements in DLBCL are often seen to non-IGH@ partners and with complex karyotypes 10. The prognostic significance of MYC rearrangement alone in DLBCL is controversial. Several studies have demonstrated the association of MYC rearrangement with poorer outcome in DLBCL patients treated with R-CHOP 6. However, recent studies have suggested that the impact of MYC is strongly influenced by BCL2 and that MYC alone does not have a worse prognosis 13, 14. MYC rearranged DLBCL may either arise de novo or may represent a high-grade transformation of a low-grade lymphoma, usually follicular lymphoma. In the latter case the MYC translocation is accompanied by a BCL2 rearrangement, so-called ‘double-hit’ (DH) lymphoma. Approximately 40% of all DH lymphomas represent transformed FL cases 15. However, 60–80% of MYC rearranged bona-fide de novo DLBCL are accompanied either by a BCL2 and/or a BCL6 rearrangement, representing DH or triple hit (TH) lymphomas 12, 14. Altogether DLBCL with DH/TH represent around 3–6% of all DLBCL and are generally refractory to standard chemotherapy regimens and have a poor prognosis 13, 14, 16. Importantly, not all patients with DLBCL morphology and DH/TH may have a dismal prognosis. Recently, attention has focused on the apparent importance of the MYC partner because it has been suggested that only cases with an IG/MYC translocation have an adverse prognosis. The development of FISH assays readily performed in paraffin sections and more recently a monoclonal antibody that specifically recognizes MYC protein have facilitated the recognition of MYC alterations in routine diagnosis. Break-apart FISH probes are considered to be the most sensitive assay for identifying chromosomal rearrangements. In addition, the use of MYC/IGH dual fusion probe helps to confirm the MYC partner 6. However, dual fusion probes for MYC/IGκ and MYC/IGλ are not commercially available. MYC protein expression has been proposed as a rapid and cost-effective screening tool to identify MYC rearrangements. Although some studies agree that finding >70% MYC+ cells correlates with MYC rearrangement 6, 13, a considerable number of cases with MYC rearrangement fall into the low MYC expression group (<40%) 12. A combined approach MYC-FISH and IHC seems advisable. More common than MYC translocations is MYC protein overexpression reported to occur in 25–30% of DLBCL cases 13, 14, 16. Most studies used a cut-off of 40% for MYC positivity. Of note, the negative prognostic impact of MYC protein expression is observed only in patients who simultaneously overexpressed BCL2 protein, so-called ‘double-expresser’ (DE). The cut-off for BCL2 protein overexpression varies in different studies, but most studies required at least 50% of tumor cells. MYC and BCL2 DE have been reported to occur in 19–34% of DLBCL patients, and to have a worse prognosis than patients who do not express any or only one protein 13, 14, 16, but better prognosis than DH/TH DLBCL, which have a dismal outcome. Interestingly, the DE cases appear more common in the ABC subtype, and it has been suggested that this may largely contribute to the known inferior survival of the ABC subtype 16. The morphological distinction between BL and DLBCL has been problematic for pathologists. GEP studies have shown that BL has a characteristic signature but that there are cases within the spectrum of DLBCL and aggressive B-cell lymphomas, which have a similar molecular BL signature or fell into an intermediate category 10, 11. The 2008 WHO classification recognized this problematic an added a provisional category of B cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (BCLU) (Figure 3) 15. BCLU is a disease of older patients presenting with nodal or extranodal disease usually in an advanced clinical stage, high lactate dehydrogenase and frequent bone marrow and CNS infiltration with a dismal prognosis. Interestingly, MYC rearrangements can be detected in 30–50% of the cases usually associated with many more chromosomal aberrations 15. The incidence of DH/TH in BCLU has been reported to be high (32%–78%).The precise morphological boundaries of this category are still not well defined. There is an ongoing discussion about how to classify aggressive lymphomas with DH/TH. One proposal is to continue classifying them based on morphology as DLBCL or BCLU or putting them together as a group of ‘DH/TH lymphomas’ regardless of the morphology of the tumor cells. The understanding of the biology of DLBCL has increased tremendously in the last 15 years. The diagnosis of DLBCL needs to integrate, in addition to standard morphology and immunohistochemistry, all available ancillary techniques. The routine use of FISH and IHC to detect MYC and BCL2 alterations/overexpression is recommended. Patients with DH and double expression of MYC and BCL2 represent poor-risk subsets in which alternative strategies should be explored 5. The distinction of GCB versus ABC-DLBCL has not yet led to differences in primary treatment. The current standard of care for most patients is R-CHOP, which has improved dramatically the outcome of DLBCL. However, for patients who fail R-CHOP, the choice of therapy is very likely to be influenced by the cell of origin 5. For example, bortezomib or BTK inhibitors have been shown to be effective in relapsed ABC-DLBCL but not in GCB subtype. On the contrary treatment with EZH2 inhibitors and BCL6 inhibitors have been shown to be effective in relapsed GCB-DLBCL. Emerging new targeted therapy will certainly influence the diagnosis and treatment of DLBCL in the near future.

Lymphoma is the fifth most common type of cancer in the United States, with 74,490 new cases estimated in 2009. Approximately 15% of patients with lymphoma have Hodgkin lymphoma; the remainder have one of the non-Hodgkin lymphomas. The incidence of non-Hodgkin lymphoma has increased steadily over recent decades. This chapter reviews the epidemiology, classification, clinical features, pathology, diagnostic evaluation, staging and prognosis, and treatment of Hodgkin and non-Hodgkin lymphoma. Other topics discussed include the acute and chronic effects of therapy for Hodgkin disease, as well as the subtypes of non-Hodgkin lymphomas, including indolent B cell lymphoma, follicular lymphoma, small lymphocytic lymphoma, mantle cell lymphoma, marginal-zone lymphoma, diffuse large B cell lymphoma (DLBCL), primary central nervous system lymphoma (PCNSL), Burkitt lymphoma, and HIV-related non-Hodgkin lymphoma. Figures illustrate the cellular appearance of Hodgkin lymphoma subtypes and DLBCL, diagnosis of DLBCL subtypes by gene expression, computed tomography and plain chest film in primary mediastinal cell lymphoma, MRI of the brain in PCNSL, and gene expression and gene expression predictors of survival among patients with DLBCL treated with rituximab, cyclophosphamide, hydroxydaunorubicin, vincristine [Oncovin], and prednisone (R-CHOP). Tables describe the Ann Arbor classification and the Cotswold modification for staging of lymphoma; the International Prognostic Score for advanced Hodgkin lymphoma; the World Health Organization classification of hematopoietic neoplasms; chromosomal translocations in non-Hodgkin lymphoma; the Eastern Cooperative Oncology Group performance scale; the International Prognostic Index for aggressive non-Hodgkin lymphoma; and the Follicular Lymphoma International Prognostic Index. This chapter has 185 references. This review contains 9 tables, 7 figures and 185 references

The high incidence of thrombosis in lymphoma is largely due to chronic inflammation and endothelial dysfunction. To elucidate the mechanisms underlying thrombus formation and fibrinolysis, we investigated interactions between circulating endothelial cells and peripheral blood mononuclear cells (MNCs), along with inflammatory signaling pathways, in patients with follicular lymphoma (FL), Hodgkin lymphoma (HL), and diffuse large B-cell lymphoma (DLBCL), independent of the presence of thrombosis, compared to healthy controls by flow cytometry, immunoblotting, and fluorometric assays. We observed increased tissue factor (TF) expression on CD31+ endothelial cells in DLBCL and FL. In DLBCL, inducible nitric oxide synthase expression was elevated in MNCs, while reduced nitrite levels correlated with an advanced clinical stage in patients with thrombosis. In lymphoma, nuclear factor kappa B (NFκB) signaling was activated in MNCs, while signal transducer and activator of transcription 3 (STAT3) activation was increased in DLBCL with thrombosis. Trans-endothelial migration of MNC was enhanced in HL, FL and DLBCL with thrombosis and reduced by inflammatory cytokine tumor necrosis factor alpha (TNF-α) that promoted platelet aggregation like interleukin-6 (IL-6) in HL and FL. Fibrinolytic analyses showed reduced tissue type plasminogen activator in lymphoma, whereas increased urokinase-type plasminogen activator (uPA) was linked to poorer total survival in DLBCL with thrombosis, suggesting a compensatory role in early thrombus resolution. These findings indicate that chronic inflammation promotes endothelial activation, dysregulated fibrinolysis, and increased vascular permeability, contributing to heightened thrombotic risk. This study provides mechanistic insight into lymphoma-associated thrombosis and identifies TF, uPA, and the inflammatory signaling pathways as potential biomarkers and therapeutic targets.

CD47 Expression Defines the Efficacy of Rituximab in Non-Germinal Center B-Cell (non-GCB) Diffuse Large B-Cell Lymphoma (DLBCL)

Low Circulating B Lymphocytes in Newly Diagnosed Follicular and Diffuse Large B Cell Lymphoma: Differences Compared to Normal Subjects and Possible Prognostic Role

To investigate the feasibility of differentiation of lymphoma, metastatic lymph nodes of squamous cell carcinoma (SCC) and papillary thyroid carcinoma (PTC) in the head and neck by single-source dual-energy spectral CT. 25 cases of non-Hodgkin lymphoma (NHL) with 236 lymph nodes, 3 cases of Hodgkin's lymphoma (HL) with 32 lymph nodes, 21 cases of SCC with 86 lymph nodes and 19 cases of PTC with 92 lymph nodes were evaluated by enhanced GSI. CT attenuation of lymph nodes in the monochromatic images at different keV levels and the iodine and water contents of these lymph nodes were measured. The slope of spectral curve was calculated using CT value at 40 keVand 90 keV. All results were analyzed with ANOVA and t test. 70 keV had the best single energy images. Normalized Hounsfield unit (NHU) of diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), T lymphoblastic lymphoma (T-LBL), HL, PTC and SCC was 0.32 ± 0.10, 0.46 ± 0.08, 0.41 ± 0.11, 0.41 ± 0.11, 0.56 ± 0.15 and 0.34 ± 0.16, respectively. Normalized iodine concentration (NIC) of them was 0.20 ± 0.08, 0.32 ± 0.08, 0.25 ± 0.09, 0.30 ± 0.12, 0.49 ± 0.18 and 0.23 ± 0.18, respectively. The slope of spectral curve (k) of them was -1.92 ± 0.55, -2.45 ± 0.60, -1.82 ± 0.57, -2.57 ± 0.54, -5.44 ± 2.41 and -1.97 ± 0.81, respectively. Compared with the NHU, there was a statistically significant difference in each pair except DLBCL and SCC, and T-LBL and HL. Compared with the NIC, there was a statistically significant difference in each pair except DLBCL and SCC, FL and HL, T-LBL and SCC, and T-LBL and HL. Compared with the slope of spectral curve, there was statistically significant difference in each pair except DLBCL and T-LBL, DLBCL and SCC, FL and HL, and T-LBL and SCC. Malignant lymph nodes of different types of diseases have certain different values of quantitative parameters in spectral CT imaging. By using CT attenuation, the shape and slope of spectral curve and the iodine content, single-source dual-energy CT may potentially provide a quantitative analysis tool for the diagnosis and differential diagnosis of lymph node alterations.

Diffuse large B cell lymphoma (DLBCL) often develops resistance and/or relapses in response to immunochemotherapy. Epigenetic modifiers are frequently mutated in DLBCL, i.e., the lysine (histone) acetyltransferases CREBBP and EP300. Mutations in CBP/p300 can prevent the proper acetylation and activation of (i) enhancer sequences of genes required for essential functions (e.g., germinal center exit and differentiation) and (ii) the tumor suppressor p53. Based on evidence that omega-3 fatty acids (ω-3 FAs) affect histone acetylation in various cancers, we investigated whether ω-3 FA docosahexaenoic acid (DHA) could modify levels of histone and p53 acetylation in three DLBCL cell lines (at different CREBBP/EP300 mutational status) versus normal B cells. Exposure to DHA at clinically attainable doses was shown to significantly alter the genome-wide levels of histone posttranslational modifications in a cell-line-dependent and dose-dependent manner. Although histone acetylation did not increase uniformly, as initially expected, levels of p53 acetylation increased consistently. Quantitative reverse transcription polymerase chain reaction results revealed significant changes in expression of multiple genes, including increased expression of CREBBP and of PRDM1 (required for differentiation into plasma cells or memory B cells). Taken together, our results provide (to our knowledge) the first characterization of the epigenetic effects of ω-3 FAs in DLBCL.

Multiple myeloma (MM) is a neoplastic proliferation of plasma cells and remains an incurable disease because of the development of drug resistance. Histone deacytylase (HDAC) inhibitors are a new class of chemotherapeutic reagents that cause growth arrest and apoptosis of neoplastic cells. Depsipeptide, a new member of the HDAC inhibitors, was found to be safe in humans and has been shown to induce apoptosis in various cancers. In order to evaluate the effects of depsipeptide, a MM cell line, U266 [interleukin (IL)-6 dependent], was analysed for viability and apoptosis. The combined effect of depsipeptide with melphalan and changes in BCL-2 family proteins (BCL-2, BCL-XL, BAX and MCL-1) were also investigated. In addition, the RPMI 8226 cell line (IL-6 independent), and primary patient myeloma cells were also analysed for apoptosis after depsipeptide treatment. Depsipeptide induced apoptosis in both U266 and RPMI 8226 cell lines in a time- and dose-dependent fashion, and in primary patient myeloma cells. We also demonstrated that depsipeptide had an additive effect with melphalan (10 micromol/l). BCL-2, BCL-XL and MCL-1 showed decreased expression in depsipeptide-treated samples. Based on recent clinical trials demonstrating minimal clinical toxicity, our study supports the future clinical utilization of depsipeptide in the management of MM.

Historical review of lymphomas.