Richter syndrome: biology, incidence, and therapeutic strategies

The multi-faceted roles of MYC in the prognosis of chronic lymphocytic leukemia

In this review, we focus on the pro-oncogene MYC, the modes of deregulation in mouse and human B-cells, its undisputable importance in the evaluation of biological prognostication of patients, but also how it impacts on response to modern therapeutics, and how it should be targeted to improve the overall survival of chronic lymphocytic lymphoma (CLL) patients. After an overview of the current understanding of the molecular dysregulation of c-MYC, we will show how CLL, both in its indolent and transformed phases, has developed among other B-cell lymphomas a tight regulation of its expression through the chronic activation of B-Cell Receptors (among others). This is particularly important if one desires to understand the mechanisms at stake in the over-expression of c-MYC especially in the lymph nodes compartment. So doing, we will show how this oncogene orchestrates pivotal cellular functions such as metabolism, drug resistance, proliferation and histologic transformation (Richter syndrome).

Updates on the Treatment of Richter's Syndrome, Including Novel Combination Approaches

Richter's syndrome (RS) or transformation of chronic lymphocytic leukemia (CLL) into a more aggressive lymphoma (e.g., diffuse large B cell lymphoma, DLBCL) is a distinct disease that portends an overall poor prognosis and remains a challenge for clinicians to identify and treat effectively. This review of the current literature focuses on the pathology, diagnosis, and management of Richter's syndrome. Clonally related RS has been found to have a worse prognosis than unrelated disease and the genomic profile of DLBCL-RS differs from that of de novo DLBCL. The standard of care therapy for RS has historically been chemoimmunotherapy; consolidative stem cell transplants have a role in improving durability of disease response. Given generally poor response rates to chemotherapy, there have been recent investigations into combination treatments with immune checkpoint inhibitors and small molecule targeted therapies, which have had mixed results. Additional studies are evaluating the use of bispecific antibodies, chimeric antigen receptor T cell therapy, and antibody drug conjugates. RS remains difficult to manage; however, advancements in the understanding of the underlying pathology of transformation and continued investigations into new therapies demonstrate promise for the future.

Molecular Mechanisms in the Transformation from Indolent to Aggressive B Cell Malignancies

Histological transformation (HT) into aggressive lymphoma is a turning point in a significant fraction of patients affected by indolent lymphoproliferative neoplasms, namely, chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), marginal zone lymphomas (MZLs), and lymphoplasmacytic lymphoma (LPL) [...].

SOHO State of the Art Updates and Next Questions | Contemporary Standard of Care Therapy for Richter's Transformation and Future Directions

Richter's transformation (RT) is a life-threatening evolution of chronic lymphocytic leukemia (CLL) into a more aggressive lymphoma, typically diffuse large B-cell lymphoma (DLBCL), marking a challenging juncture in CLL management due to the associated poor prognosis and limited treatment options. This review delves into the current therapeutic landscape for RT. Despite the modest efficacy of traditional chemoimmunotherapy (CIT) regimens such as R-CHOP and its variations, this regimen remains the most commonly recommended standard of care. Multiple therapeutic strategies are under investigation, including targeted kinase inhibitors, checkpoint inhibitors, bispecific antibodies, and CAR T therapy. Given the complex nature of RT and the evolving therapeutic paradigms, ongoing research is imperative to refine treatment strategies and integrate novel therapeutic agents to enhance survival and quality of life for people with RT. Given the lack of a clear standard of approach in the management of RT, patients with RT should be prioritized to enroll on clinical trials where feasible.

The preclinical discovery and development of zanubrutinib for the treatment of chronic lymphocytic leukemia

INTRODUCTION

The history of treating chronic lymphocytic leukemia (CLL) inflected in 2014 with the Food and Drug Administration's (FDA) approval of ibrutinib, the first-in-class small molecule inhibitor of the Bruton's tyrosine kinase (BTK). Zanubrutinib is a 2nd generation covalent BTK inhibitor developed and manufactured by BeiGene.

AREAS COVERED

In this review, the authors trace the arc of zanubrutinib development from the preclinical phase through the two landmark phase 3 studies in the CLL space, ALPINE and SEQUOIA. The authors cover contemporary management strategies in CLL and highlight the areas of need that zanubrutinib was designed to mitigate.

EXPERT OPINION

Zanubrutinib entered a fray of novel, exciting therapies for CLL. As the second of two 2nd generation covalent BTK inhibitors its path to prominence in CLL management was narrow. Emphasis during development on kinase selectivity and enhanced bioavailability identified a molecule with superior efficacy and tolerability; hierarchical endpoints in trial design allowed for efficient acquisition of comparative data. Zanubrutinib is endorsed by the National Comprehensive Cancer Network as a preferred, category 1 recommended treatment choice for CLL. Future efforts in combination therapies and response-directed treatment breaks will hopefully lead to still further improvements in use.

Survival analysis of a 16-year cohort of follicular lymphoma patients receiving systemic treatment in Brazil

Introduction

Follicular lymphoma (FL) is a common type of non-Hodgkin lymphoma that is incurable but often follows an indolent course. While survival is improving thanks to advances in diagnosis, supportive care, and new therapies, understanding outcomes and their impact on overall survival is still limited. There are few studies on FL in Brazil, so this study aims to evaluate the patient's profile, morbidity and mortality treated by the Brazilian national health service (SUS) and evaluate risk factors associated with treatment failure.

Methods

This is a nationwide 16 years cohort with patients that underwent chemotherapy in the SUS (2000-2015). The Kaplan-Meier method was used to estimate survival until treatment failure, and the Cox proportional hazards model was used to evaluate risk factors.

Results

The cohort included 10,009 patients and survival rates were 73.3%, 45.3%, and 30.7% for the first, fifth and 10th year respectively. The median overall survival was approximately 4.1 years. The most used regimen was CHOP (13%), followed by CVP (9.7%) and R-CHOP (3.3%). Four hundred and ninety-eight patients (4.9%) used rituximab-containing regimens. Univariate analysis indicated worse survival rates for male patients, those over 65 years of age, clinical stage III or IV and those using non-rituximab-containing regimens. The health technology performance assessment related to oncology schemes for FL suggests that rituximab-based regimens has shown best survival probability (0.52 CI 0.39-0.69) in 78 months of follow up with a HR 1.5 times better than other schemes (HR 0.67; CI 0.55-0.81).

Discussion

In light of the substantial advancements achieved by the SUS, there is a need for CONITEC to expedite decision-making processes in order to enhance patients access to new oncology drugs. This should be done while upholding health technology assessment standards. Timely integration and sufficient funding for oncology services have the potential to save lives, especially when compared to the treatments available within SUS at that time.

Orbital Richter Transformation With Subsequent Orbital MALT-type Lymphoma in a Patient With Chronic Lymphocytic Leukemia

A 74-year-old man with a history of chronic lymphocytic leukemia (CLL) presented with large salmon-colored patch lesions along the inferior fornix and superotemporal conjunctiva of the OS. The patient underwent an incisional biopsy of the lesions, which showed a CLL with areas of large B-cell lymphoma, consistent with Richter transformation. Following medical and radiation-based therapy of these lesions, the patient returned 3 months later with inferomedial preseptal swelling in the contralateral eye, which biopsy proved to be recurrent/resistant low-grade CLL with a posttreatment extranodal marginal zone B-cell lymphoma pattern. This case exemplifies a rare presentation of CLL with Richter transformation and a recurrent/resistant posttreatment orbital CLL with a marginal zone B-cell lymphoma-like pattern.

Applications of 18F-Fluorodesoxyglucose PET Imaging in Leukemia

The main finding that 18F-FDG PET imaging can reveal in patients with leukemias is the presence of bone marrow (BM) infiltration in both acute or chronic forms. This ability can influence and guide the use of BM biopsy but also assess to therapy response. Additionally 18F-FDG PET imaging has been reported as particularly useful for the diagnosis of leukemias in patients with non specific symptoms. In the case of acute leukemias it revealed also a role for the evaluation of extramedullary forms while in the case of chronic forms a role for the assessment of Richter transformation has been reported.

Are we closer to a standard of care for Richter's syndrome? Novel treatments on the horizon

INTRODUCTION

The therapeutic landscape for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has significantly evolved over the past decade with dramatically improved outcomes with the introduction of targeted therapies. This unfortunately has not been the case for Richter transformation (RT), the histologic transformation to a more aggressive lymphoma, most typically diffuse large B-cell lymphoma (DLBCL). As such, RT continues to be one of the most challenging complications of CLL/SLL. Historically, RT has a poor response to treatment, with a minority reaching complete remission (CR) and overall survival (OS) being less than a year.

AREAS COVERED

The focus of this review is to discuss the effectiveness of commonly used regimens, and review existing data for emerging regimens being examined in ongoing clinical trials to improve prognosis and outcomes in patients with RT. Despite extensive efforts to optimize therapies for RT, there is still no generalized consensus on either first-line treatment regimens or regimens in the relapsed/refractory setting. RT continues to carry a high mortality rate without durable response to current therapeutic agents.

EXPERT OPINION

Ongoing and future research may identify novel treatment approaches that will eventually improve outcomes for patients with RT. The optimal care for RT patients is a clinical trial, when feasible.

Treatment of Richter Transformation of Chronic Lymphocytic Leukemia in the Modern Era

Richter Transformation (RT) refers to the development of an aggressive lymphoma in the setting of chronic lymphocytic leukemia (CLL). While many variants of RT are recognized, diffuse large B-cell lymphoma (RT-DLBCL) is the most common (80%), followed by Hodgkin’s lymphoma (RT-HL, 19%). Diagnosis is based upon histologic evaluation of clinically suspicious lymph nodes. Positron emission tomography (PET) may be used to select the node of interest for biopsy. Although clonality testing is not a prerequisite of RT diagnosis, it has significant implications for survival. Clonally related DLBCL carries the worst prognosis with a median overall survival (OS) of less than one year in the era of combination chemotherapies with or without anti-CD20 antibodies. Prognosis has improved with the use of stem cell transplant and newer agents such as targeted therapy and newer forms of immunotherapy. Consideration of a clinical trial is encouraged. This review describes our current understanding of RT and focuses on treatment of RT-DLBCL, including clinical trials in progress and new therapies in development. We also report an illustrative example of a patient with clonally related DLBCL who survived two years after diagnosis without the use of combination chemotherapy.

Outcomes of CD19-directed Chimeric Antigen Receptor T-cell Therapy for Transformed Non-follicular Lymphoma

BACKGROUND

CD19-directed chimeric antigen receptor (CAR)-T cell therapies with axicabtagene ciloleucel (axi-cel) or tisagenlecleucel (tisa-cel) are approved for the treatment of relapsed or refractory large B-cell lymphoma (LBCL), including de novo diffuse large B-cell lymphoma (DLBCL), primary mediastinal B-cell lymphoma (PMBCL), and transformed follicular lymphoma (tFL). Transformed non-follicular lymphomas (tNFLs) (including transformed marginal zone lymphoma [tMZL] and transformed chronic lymphocytic leukemia/small lymphocytic lymphoma [tCLL/SLL]) were not included in their respective pivotal studies.

OBJECTIVES

To evaluate the outcomes of axi-cel and tisa-cel in tNFL patients, including those who received ibrutinib concomitantly through apheresis, lymphodepletion, and CAR-T infusion.

STUDY DESIGN

This single-center retrospective study included all patients with tCLL/SLL, tMZL, tFL, and DLBCL/PMBCL treated with CAR-T therapy outside of a clinical trial setting from November 2017 to May 2021 at Moffitt Cancer Center, Tampa, Florida, USA. We analyzed the outcomes in patients with tCLL/SLL or tMZL and compared that to patients with DLBCL/tFL.

RESULTS

The study included 134 patients who received a total of 136 CAR-T treatments (111 with axi-cel and 25 with tisa-cel). Ninety patients had de novo DLBCL/PMBCL; 23 had tFL; and 21 had tNFL (12 with tMZL and 9 with tCLL/SLL). The overall response and complete response rates for tCLL/SLL were 66.7% and 55.6%, respectively; and for tMZL they were 92.9% and 71.4%, respectively. The overall response and complete response rates between tNFL and the DLBCL/tFL were not different (P = .92 and .81, respectively). At a median follow-up of 21.3 months, the median progression-free survival (PFS) for tCLL/SLL was 5.4 months (95% CI, 0.8-not assessable [NA]); for tMZL, the median PFS was not reached (NR) (95% CI, 2.3-NA), and for DLBCL/tFL the median PFS was 14.3 months (95% CI, 5.6-NA) (P = .58). The estimated 1-year PFS rate for tCLL/SLL was 29.6% (95% CI, 5.2-60.7), and for tMZL was 50.0% (95% CI, 22.9-72.2). The estimated 1-year PFS rate for tNFL was 42.7% (95% CI, 22.4-61.6), and for DLBCL/tFL was 53.0% (95% CI, 42.3-62.5). The median overall survival was NR (95% CI, 9.2-NA) for tCLL/SLL, 27.1 months (95% CI, 8.5-NA) for tMZL, and NR (95% CI, 17.4-NA) for DLBCL/tFL (P = .79). Compared to the DLBCL/tFL cohort, tNFL patients were more likely to develop immune cellular-associated neurologic syndrome and receive tocilizumab (P = .04 and .01, respectively, after controlling for CAR-T product) and with possibly higher incidence of grade 3 or worse cytokine release syndrome (P = .07). Two patients in the tNFL cohort died of treatment related toxicity after receiving axi-cel. Six tNFL patients received ibrutinib concurrently with tisa-cel with one case of grade 3 or higher CRS/ICANS that rapidly resolved and no other severe toxicities.

CONCLUSION

Our case series supports the use of CD19 CAR T cell therapy in r/r tCLL/SLL and tMZL. The use of concurrent ibrutinib with tisa-cel in tNFL was associated with manageable toxicity in tNFL.

Immunological Aspects of Richter Syndrome: From Immune Dysfunction to Immunotherapy

Richter Syndrome (RS) is defined as the development of an aggressive lymphoma in patients with a previous or simultaneous diagnosis of chronic lymphocytic leukemia (CLL). Two pathological variants of RS are recognized: diffuse large B-cell lymphoma (DLBCL)-type and Hodgkin lymphoma (HL)-type RS. Different molecular mechanisms may explain the pathogenesis of DLBCL-type RS, including genetic lesions, modifications of immune regulators, and B cell receptor (BCR) pathway hyperactivation. Limited data are available for HL-type RS, and its development has been reported to be similar to de novo HL. In this review, we focus on the immune-related pathogenesis and immune system dysfunction of RS, which are linked to BCR over-reactivity, altered function of the immune system due to the underlying CLL, and specific features of the RS tumor microenvironment. The standard of care of this disease consists in chemoimmunotherapy, eventually followed by stem cell transplantation, but limited possibilities are offered to chemo-resistant patients, who represent the majority of RS cases. In order to address this unmet clinical need, several immunotherapeutic approaches have been developed, namely T cell engagement obtained with bispecific antibodies, PD-1/PD-L1 immune checkpoint blockade by the use of monoclonal antibodies, selective drug delivery with antibody-drug conjugates, and targeting malignant cells with anti-CD19 chimeric antigen receptor-T cells.

Necrotic herpes simplex lymphadenitis imitating Richter's transformation in a patient with chronic lymphocytic leukemia - A case report

Richter Transformation (RT) is the phenomenon of progression from Chronic Lymphocytic Leukemia (CLL) into an aggressive Large-Cell Lymphoma and is typically characterized by diffuse lymphadenopathy combined with the classical "B symptoms". While rare, other causes of sudden onset diffuse lymphadenopathy in patients with CLL can occur; one of the rarest being necrotic herpes simplex lymphadenitis. We report a case that presented similarly to Richter Transformation including PET-CT scan findings consistent with RT but was histologically proven to be necrotic herpes simplex lymphadenitis. We identified less than 20 reported cases of this phenomenon in English language literature. Our patient was successfully treated with appropriate antiviral therapy due to timely recognition of the correct disease process. Our case reinforces the importance of maintaining diagnostic suspicion when approaching sudden onset lymphadenitis in this patient population.

A clinical case of the effective combined use of BCL-2 and PI3K inhibitors in the treatment of a patient with an unfavorable chronic lymphocytic leukemia with transformation into diffuse large B-cell lymphoma (Richter’s syndrome)

Understanding the molecular biological basis of chronic lymphocytic leukemia (CLL) pathogenesis and stratification of patients into risk groups has now led to significant advances in treatment. New targeted drugs with different mechanisms of action (bruton’s tyrosine kinase inhibitors, bCL-2 inhibitors, pI3K inhibitors) have significantly improved the prognosis of high-risk CLL patients. In some CLL cases the nodular tumor component can change to a more aggressive subtype of lymphoma (often diffuse large b-cell) with preservation of the small-cell leukemic component with the CLL phenotype (Richter’s syndrome), usually characterized by rapid progression and poor prognosis. The issue of treatment efficacy in patients with Richter’s syndrome still remains unresolved. The results of new drugs clinical trials are often contradictory and cannot yet be recommended for routine use in clinical practice. The low incidence of Richter’s syndrome, the lack of a unified view of the pathogenesis and therapy approaches make the search for effective drugs an urgent task, so each clinical observation is of undoubted interest.A clinical case of CLL patient with unfavorable molecular cytogenetic risk and transformation into diffuse large b-cell lymphoma (Richter’s syndrome) is presented. The combined use of bCL-2 inhibitors (venetoclax) and pI3K (duvelisib) led to the achievement of partial remission followed by a gradual increase in the positive antitumor effect.

Richter Syndrome: From Molecular Pathogenesis to Druggable Targets

Richter syndrome (RS) represents the occurrence of an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), in patients with chronic lymphocytic leukemia (CLL). Most cases of RS originate from the direct transformation of CLL, whereas 20% are de novo DLBCL arising as secondary malignancies. Multiple molecular mechanisms contribute to RS pathogenesis. B-cell receptor (BCR) overreactivity to multiple autoantigens is due to frequent stereotyped BCR configuration. Genetic lesions of TP53, CDKN2A, NOTCH1 and c-MYC deregulate DNA damage response, tumor suppression, apoptosis, cell cycle and proliferation. Hyperactivation of Akt and NOTCH1 signaling also plays a role. Altered expression of PD-1/PD-L1 and of other immune checkpoints leads to RS resistance to cytotoxicity exerted by T-cells. The molecular features of RS provide vulnerabilities for therapy. Targeting BCR signaling with noncovalent BTK inhibitors shows encouraging results, as does the combination of BCL2 inhibitors with chemoimmunotherapy. The association of immune checkpoint inhibitors with BCL2 inhibitors and anti-CD20 monoclonal antibodies is explored in early phase clinical trials with promising results. The development of patient-derived xenograft mice models reveals new molecular targets for RS, exemplified by ROR1. Although RS still represents an unmet medical need, understanding its biology is opening new avenues for precision medicine therapy.

Hodgkin Lymphoma and Hairy Cell Leukemia Arising from Chronic Lymphocytic Leukemia: Case Reports and Literature Review

Richter’s syndrome represents the progression of chronic lymphocytic leukemia (CLL) to more aggressive diseases, most frequently diffuse large B-cell lymphoma, while Hodgkin’s lymphoma (HL) and hairy cell leukemia (HCL) are rarely described. The first case involved a 67-year-old man with a diagnosis of a high-risk stage-II CLL treated with rituximab and ibrutinib, developed a HL nodular sclerosis variant after three months of therapy for CLL. After achieving a complete remission for HL and ibrutinib cessation because of drug-related cardiotoxicity, the patient relapsed after five months off-therapy and died due to disease progression after two cycles of brentuximab-vedotin. The second case involved an 83-year-old female with a diagnosis of stage-IV CLL treated with rituximab plus bendamustine who developed a HCL eight years later. Pentostatin was unsuccessfully employed as upfront HCL therapy, and the patient was then switched to rituximab while in remission for CLL. In conclusion, Richter’s transformation risk rate might be higher in patients treated with novel targeted therapies, and multiparametric flow cytometry and lymph node biopsy at relapse could help in early identifying small clones. The treatment of predominant neoplasia is mandatory, and disease-specific drugs are administered; however, clinical efficacy might be lower in these patients.

Integrin Signaling Shaping BTK-Inhibitor Resistance

Integrins are adhesion molecules that function as anchors in retaining tumor cells in supportive tissues and facilitating metastasis. Beta1 integrins are known to contribute to cell adhesion-mediated drug resistance in cancer. Very late antigen-4 (VLA-4), a CD49d/CD29 heterodimer, is a beta1 integrin implicated in therapy resistance in both solid tumors and haematological malignancies such as chronic lymphocytic leukemia (CLL). A complex inside-out signaling mechanism activates VLA-4, which might include several therapeutic targets for CLL. Treatment regimens for this disease have recently shifted towards novel agents targeting BCR signaling. Bruton’s tyrosine kinase (BTK) is a component of B cell receptor signaling and BTK inhibitors such as ibrutinib are highly successful; however, their limitations include indefinite drug administration, the development of therapy resistance, and toxicities. VLA-4 might be activated independently of BTK, resulting in an ongoing interaction of CD49d-expressing leukemic cells with their surrounding tissue, which may reduce the success of therapy with BTK inhibitors and increases the need for alternative therapies. In this context, we discuss the inside-out signaling cascade culminating in VLA-4 activation, consider the advantages and disadvantages of BTK inhibitors in CLL and elucidate the mechanisms behind cell adhesion-mediated drug resistance.

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma With Secondary Acquisition of t(11;14)(q13;q32)/CCND1-IGH: A Rare Variant Of Richter Transformation to Mantle Cell Lymphoma

INTRODUCTION

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) occasionally undergoes Richter transformation, mostly to diffuse large B-cell lymphoma, but its evolution to other types of B-cell lymphoma is rare. We report a CLL evolved to mantle cell lymphoma by acquiring t(11;14)(q13;q32); CCND1-IGH.

METHOD

A Retrospective review of clinical and laboratory data.

RESULTS

A 39-year-old male patient was diagnosed with CLL/SLL, and was initially followed without specific treatment, but subsequently received chlorambucil/fludarabine/rituximab due to exacerbated lymphocytosis. While his CLL/SLL waned and waxed, the immunophenotype and genotype of neoplastic B-cells remained unchanged, without cyclin D1 expression and CCND1-IGH fusion. Eleven years after the diagnosis, the patient's disease showed evidence of progression. Bone marrow examination demonstrated "CLL" with the morphology and immunophenotype similar to those seen in the previous biopsies. Unexpectedly, the neoplastic B-cells demonstrated cyclin D1 expression and harbored t(11;14)(q13;q32); CCND1-IGH, suggesting a clonal evolution to mantle cell lymphoma. He subsequently received cytoreductive chemotherapy followed by allogenic bone marrow transplant and remained in remission since then.

CONCLUSION

The retention of immunophenotype suggests a clonal relationship between CLL/SLL and mantle cell lymphoma. While the acquisition of t(11;14)(q13;q32); CCND1-IGH likely alters the disease course, the pathogenesis of this illegitimate translocation in CLL remains to be studied.

CARD9 Forms an Alternative CBM Complex in Richter Syndrome

Simple Summary

The transformation process of chronic lymphocytic leukemia into an aggressive lymphoma, called Richter syndrome (RS), is incompletely understood, and therapeutic options are limited. Here, we report CARD9 to be expressed in a subset of RS tissue specimen and in the first and only available RS cell line, U-RT1. In U-RT1, CARD9 attaches to BCL10 and MALT1, and knockdown of CARD9 leads to a significant reduction in cell viability. We hypothesized that CARD9 plays an oncogenic role in RS through the activation of NF-κB signaling. Our findings may help to extend the current knowledge about the pathogenesis of RS and promote the development of targeted therapies for this aggressive disease.

Abstract

Richter syndrome (RS) is defined as the transformation of chronic lymphocytic leukemia (CLL) into an aggressive lymphoma, mostly diffuse large B-cell lymphoma (DLBCL). Despite intensive therapy, patients with RS have an unfavorable clinical outcome. The detailed pathobiology of Richter transformation still needs to be elucidated. Here, we report high mRNA and protein levels of CARD9 in the RS cell line U-RT1. Co-immunoprecipitation revealed the assembly of a CBM complex using CARD9 instead of CARD11. CARD9 is known to be an activator of NF-кB signaling in myeloid cells. U-RT1 Western blot analyses showed phosphorylation of IκB as well as IKK, indicating a constitutively active canonical NF-кB pathway. This was further supported by the significant reduction in cell viability and CYLD cleavage products after CARD9 siRNA knockdown. We also showed immunostaining for CARD9 in 53% of cases analyzed in a series of RS tissue specimens, whereas other lymphomas rarely show CARD9 expression. This is the first report on ectopic expression and function of CARD9 in an aggressive B-cell lymphoma. Our findings suggest that CARD9 may contribute to the pathogenesis of RS.

First case of chronic cell leukemia discovered incidentally in extra-saccular inguinal lymph node during laparoscopic bilateral inguinal hernia repair. Case report and literature review

Introduction

Chronic cell leukemia discovered incidentally in extra-saccular inguinal lymph node during laparoscopic bilateral inguinal hernia repair is extremely rare.

Presentation of case

62-year-old Romanian male presented at the outpatient general surgery clinic in April 2019 complaining of bilateral inguinal swelling that gradually increased in size mainly on right side and was diagnosed with bilateral inguinal hernia. During the laparoscopic repair of the hernia, a large lymph node in the left femoral canal was incidentally observed. Histopathologic, immunohistochemical, and flowcytometric evaluation of the excised specimen confirmed chronic lymphocytic leukemia/small lymphocytic lymphoma.

Discussion

Whole body CT showed supra and infra-diaphragmatic lymphadenopathy, and few small subsolid pulmonary nodules, possibly metastatic. Splenomegaly and pancreatomegaly were also noted, suggesting lymphomatoid infiltration.

Conclusion

There is need for cautious inspection and meticulous palpation of the inguinal area for any lymphadenopathy during routine inguinal hernia repair.

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Chronic lymphocytic leukemia (CLL) is a B-cell lymphoid neoplasm.

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CLL diagnosed incidentally in extra-saccular inguinal lymph node during inguinal hernia repair is extremely rare.

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Surgeons need inspection and meticulous palpation of inguinal area for any lymphadenopathy during inguinal hernia repair.

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No advantage of early initiation of treatment on early stages of chronic lymphocytic leukemia

Autologous and allogeneic hematopoietic cell transplantation for diffuse large B-cell lymphoma-type Richter syndrome

Richter syndrome (RS) represents a transformation from chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) to aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL), which is associated with a dismal prognosis. Patients with DLBCL-RS have poor outcomes with DLBCL-directed therapy; thus, consolidation with hematopoietic cell transplantation (HCT) has been used, with durable remissions observed. Studies reporting HCT outcomes in patients with DLBCL-RS have been small, have not evaluated the prognostic impact of cytogenetic risk factors, and were conducted prior to the era of novel targeted therapy of CLL/SLL. We performed a Center for International Blood and Transplant Research registry study evaluating outcomes after autologous HCT (auto-HCT; n = 53) and allogeneic HCT (allo-HCT; n = 118) in patients with DLBCL-RS treated in the modern era. More auto-HCT recipients were in complete response (CR) at HCT relative to allo-HCT recipients (66% vs 34%), whereas a higher proportion of allo-HCT recipients had 17p deletion (33% vs 7%) and had previously received novel agents (39% vs 10%). In the auto-HCT cohort, the 3-year relapse incidence, progression-free survival (PFS), and overall survival (OS) were 37%, 48%, and 57%, respectively. Among allo-HCT recipients, the 3-year relapse incidence, PFS, and OS were 30%, 43%, and 52%, respectively. In the allo-HCT cohort, deeper response at HCT was associated with outcomes (3-year PFS/OS, 66%/77% CR vs 43%/57% partial response vs 5%/15% resistant; P < .0001 for both), whereas cytogenetic abnormalities and prior novel therapy did not impact outcomes. In our study, HCT resulted in durable remissions in therapy-sensitive patients with DLBCL-RS treated in the era of targeted CLL/SLL therapy, including patients with high-risk features.

Concomitant Diagnosis of Plasmablastic Lymphoma and Chronic Lymphocytic Leukemia: A Rare Phenomenon

Plasmablastic lymphoma (PBL) is a rare, aggressive non-Hodgkin lymphoma which shows blastic morphology and an immunophenotype of plasma cell differentiation while chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma is an indolent B-cell lymphoma and has a variable clinical course. A CLL transforming into a PBL and the coexistence of CLL with PBL are both extremely rare findings. We report an unusual case of a 72-year-old HIV-negative male who presented with a gingival swelling which was diagnosed as PBL with simultaneous CLL in the blood and bone marrow. Further, in this case, the PBL spontaneously regressed postbiopsy adding to the peculiarity and rarity of this case. This could be due to immune system modulation and can open up a new window to the treatment strategies of PBL in the future.

Reduced-intensity conditioning hematopoietic stem cell transplantation for chronic lymphocytic leukemia and Richter's transformation

Allogeneic hematopoietic stem cell transplantation (HSCT) may potentially cure patients with chronic lymphocytic leukemia (CLL) and Richter's transformation (CLL-RT) or CLL without RT, but the impact of novel agents on HSCT is unclear. CLL-RT patients have a grave prognosis, and their outcomes after HSCT are uncertain. We conducted a retrospective analysis of all 58 CLL patients, including 23 CLL-RT patients, who underwent reduced intensity conditioning (RIC) HSCT at Memorial Sloan Kettering Cancer Center (New York, NY) between September 2006 and April 2017. With a median follow-up of 68 months (range, 24-147 months), 5-year progression-free survival (PFS) was 40% (95% confidence interval [CI], 28%-56%), and overall survival (OS) was 58% (95% CI, 48%-74%). The 1-year graft-versus-host disease/relapse-free survival (GRFS) was 38% (95% CI, 25%-50%). Patients with CLL-RT and CLL patients without RT had comparable outcomes. In both cohorts, treatment-sensitive response and ≤3 previous lines of therapy produced superior PFS and OS. Outcomes were agnostic to adverse cytogenetic and molecular features. Novel agents did not have a negative impact on HSCT outcomes. Total body irradiation (TBI)-containing RIC yielded inferior PFS, OS, and GRFS. CLL-RT patients older than age 55 years who had an HSCT Comorbidity Index score of ≥2 demonstrated inferior OS. This study, which is the largest series of RIC-HSCT for patients with CLL-RT, provides evidence supporting RIC-HSCT in early remission courses for patients with CLL-RT and poor-risk CLL patients. TBI-containing RIC should be considered with caution.

Classical Hodgkin Lymphoma Presenting as a Sigmoid Mass

Primary classical Hodgkin lymphoma (CHL) in the colon is exceedingly rare and shares many histologic features with other lymphoproliferative disorders in the gastrointestinal tract. Here we report a case of CHL forming a sigmoid mass. An elderly man with a past medical history of mantle cell lymphoma presented with constipation. Imaging revealed an ulcerated, circumferential mass in the sigmoid colon. Endoscopic biopsy of the mass showed ulcerated colonic mucosa with an underlying diffuse mixed inflammatory infiltrate admixed with Hodgkin and Reed-Sternberg cells. Immunohistochemistry was performed to characterize these cells. They were weakly positive for Pax-5, strongly positive for CD30, variably positive for CD15, and negative for CD45, CD20, CD3, and SOX-11. In situ hybridization was positive for Epstein-Barr virus (EBV) and negative for cytomegalovirus or herpes simplex virus. This immunophenotype is diagnostic for CHL in the clinical context of a large mass. It is not possible in this case to determine whether this is de novo CHL or progression from a precursor lesion like EBV-positive mucocutaneous ulcer. Since diagnosis, this patient underwent colectomy followed by chemotherapy and has remained in complete remission.

The Evolving Landscape of Chronic Lymphocytic Leukemia on Diagnosis, Prognosis and Treatment

The knowledge of chronic lymphocytic leukemia (CLL) has progressively deepened during the last forty years. Research activities and clinical studies have been remarkably fruitful in novel findings elucidating multiple aspects of the pathogenesis of the disease, improving CLL diagnosis, prognosis and treatment. Whereas the diagnostic criteria for CLL have not substantially changed over time, prognostication has experienced an expansion with the identification of new biological and genetic biomarkers. Thanks to next-generation sequencing (NGS), an unprecedented number of gene mutations were identified with potential prognostic and predictive value in the 2010s, although significant work on their validation is still required before they can be used in a routine clinical setting. In terms of treatment, there has been an impressive explosion of new approaches based on targeted therapies for CLL patients during the last decade. In this current chemotherapy-free era, BCR and BCL2 inhibitors have changed the management of CLL patients and clearly improved their prognosis and quality of life. In this review, we provide an overview of these novel advances, as well as point out questions that should be further addressed to continue improving the outcomes of patients.

Hypercalcemia in Small Lymphocytic Lymphoma with an Elevated Parathyroid Hormone-Related Peptide Associated with Early Richter Transformation

Hypercalcemia in malignancy is associated with multiple mechanisms and occurs in up to 20–30% of cancer patients. We report a case of small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL) associated with hypercalcemia and an elevation in parathyroid hormone-related peptide (PTHrP) in the setting of a Richter transformation. Real-time reverse transcriptase PCR on lymph node biopsy specimens obtained before and after transformation showed an 8-fold increase in PTHrP mRNA levels and about 2-fold decrease in the levels of its cognate receptor PTHR1. The findings of this case suggest that parathyroid hormone-related peptide might be useful in monitoring a specific group of patients with SLL/CLL who develop hypercalcemia during the course of their disease and could suggest an autocrine-like mechanism involving PTHrP in Richter transformation.

Richter's transformation as leptomeningeal infiltration in a chronic lymphocytic leukemia patient receiving venetoclax. Could blood-brain barrier be a disease "sanctuary" during venetoclax treatment?

Our unique case of Richter's Transformation presenting as leptomeningial infiltration in a CLL patient receiving venetoclax raises questions on whether the drug penetrates the blood-brain barrier and at what extend, especially in reduced doses given for drug-drug interactions.

U-RT1 - A new model for Richter transformation

The advent of highly effective treatments targeting the disease biology of chronic lymphocytic leukemia (CLL) has transformed the therapeutic field tremendously. However, transformation into an aggressive B-cell lymphoma, called Richter syndrome (RS), remains highly challenging since the treatment options for this condition are still insufficient. Exploratory drug testing and experimental studies are restricted by the lack of satisfactory models. We have established U-RT1, a cell line derived from a highly proliferating RS clonally related to the patient's underlying CLL. The cell line shows morphological features and an immunophenotype of RS-DLBCL (non-GCB). Molecular analysis revealed a complex karyotype with driver aberrations characteristic for RS such as loss of TP53 and CDKN2A. Furthermore, U-RT1 displays a chromosomal gain of the NOTCH1 gene locus and strong immunoreactivity for BCL-2. These features suggest that U-RT1 is the first eligible model system for investigations on the pathogenesis of RS and novel treatment options.

Microenvironment Remodeling and Subsequent Clinical Implications in Diffuse Large B-Cell Histologic Variant of Richter Syndrome

Introduction

Richter Syndrome (RS) is defined as the development of an aggressive lymphoma in the context of Chronic Lymphocytic Leukemia (CLL), with a Diffuse Large B-Cell Lymphoma (DLBCL) histology in 95% cases. RS genomic landscape shares only a few features with de novo DLBCLs and is marked by a wide spectrum of cytogenetic abnormalities. Little is known about RS microenvironment. Therapeutic options and efficacy are limited, leading to a 12 months median overall survival. The new targeted treatments usually effective in CLL fail to obtain long-term remissions in RS.

Methods

We reviewed available PubMed literature about RS genomics, PD-1/PD-L1 (Programmed Death 1/Programmed Death Ligand 1) pathway triggering and subsequent new therapeutic options.

Results

Data from about 207 patients from four landmark papers were compiled to build an overview of RS genomic lesions and point mutations. A number of these abnormalities may be involved in tumor microenvironment reshaping. T lymphocyte exhaustion through PD-L1 overexpression by tumor cells and subsequent PD-1/PD-L1 pathway triggering is frequently reported in solid cancers. This immune checkpoint inhibitor is also described in B lymphoid malignancies, particularly CLL: PD-1 expression is reported in a subset of prolymphocytes from the CLL lymph node proliferation centers. However, there is only few data about PD-1/PD-L1 pathway in RS. In RS, PD-1 expression is a hallmark of recently described « Regulatory B-cells », which interact with tumor microenvironment by producing inhibiting cytokines such as TGF-β and IL-10, impairing T lymphocytes anti-tumoral function. Based upon the discovery of high PD-1 expression on tumoral B lymphocyte from RS, immune checkpoint blockade therapies such as anti-PD-1 antibodies have been tested on small RS cohorts and provided heterogeneous but encouraging results.

Conclusion

RS genetic landscape and immune evasion mechanisms are being progressively unraveled. New protocols using targeted treatments such as checkpoint inhibitors as single agents or in combination with immunochemotherapy are currently being evaluated.

Applications of PET in Diagnosis and Prognosis of Leukemia

As a malignant hematopoietic stem cell disease, leukemia remains life-threatening due to its increasing incidence rate and mortality rate. Therefore, its early diagnosis and treatment play a very important role. In the present work, we systematically reviewed the current applications and future directions of positron emission tomography (PET) in patients with leukemia, especially ¹⁸F-FDG PET/CT. As a useful imaging approach, PET significantly contributes to the diagnosis and treatment of different types of leukemia, especially in the evaluation of extramedullary infiltration, monitoring of leukemia relapse, detection of Richter’s transformation (RT), and assessment of the inflammatory activity associated with acute graft versus host disease. Future investigations should be focused on the potential of PET/CT in the prediction of clinical outcomes in patients with leukemia and the utility of novel radiotracers.

The Occurrence of Richter’s Syndrome during Treatment with Obinutuzumab and Chlorambucil

Chronic lymphocytic leukaemia is a slow-growing leukaemia of developing B-lymphocytes, which may transform to an aggressive lymphoma known as Richter's syndrome. While Richter's syndrome can present in untreated or relapsed-refractory cases, it may occur upon the commencement of less intensity treatment regimens. We present a case of Richter's syndrome following treatment with chlorambucil and obinutuzumab and review of available literature on the topic.

Unsupervised machine learning and prognostic factors of survival in chronic lymphocytic leukemia

OBJECTIVE

Unsupervised machine learning approaches hold promise for large-scale clinical data. However, the heterogeneity of clinical data raises new methodological challenges in feature selection, choosing a distance metric that captures biological meaning, and visualization. We hypothesized that clustering could discover prognostic groups from patients with chronic lymphocytic leukemia, a disease that provides biological validation through well-understood outcomes.

METHODS

To address this challenge, we applied k-medoids clustering with 10 distance metrics to 2 experiments ("A" and "B") with mixed clinical features collapsed to binary vectors and visualized with both multidimensional scaling and t-stochastic neighbor embedding. To assess prognostic utility, we performed survival analysis using a Cox proportional hazard model, log-rank test, and Kaplan-Meier curves.

RESULTS

In both experiments, survival analysis revealed a statistically significant association between clusters and survival outcomes (A: overall survival, P = .0164; B: time from diagnosis to treatment, P = .0039). Multidimensional scaling separated clusters along a gradient mirroring the order of overall survival. Longer survival was associated with mutated immunoglobulin heavy-chain variable region gene (IGHV) status, absent Zap 70 expression, female sex, and younger age.

CONCLUSIONS

This approach to mixed-type data handling and selection of distance metric captured well-understood, binary, prognostic markers in chronic lymphocytic leukemia (sex, IGHV mutation status, ZAP70 expression status) with high fidelity.

Allogeneic hematopoietic cell transplantation is an effective treatment for patients with Richter syndrome: A systematic review and meta-analysis

Efficacy of conventional chemoimmunotherapy is limited in patients with Richter syndrome (RS) with anticipated median overall survival (OS) of less than 10 months. Allogeneic hematopoietic cell transplantation (allo-HCT) is commonly offered as a consolidative treatment option in RS. To our knowledge, there are no randomized controlled studies that have compared allo-HCT against other therapies in RS; available allo-HCT data are limited to small case series from single-institution or registry studies. We performed a systematic review and meta-analysis to assess the totality of evidence regarding the efficacy (or lack thereof) of allo-HCT for RS. We extracted data on post-allograft outcomes related to benefits (overall response rate [ORR], complete remission [CR], OS, and progression-free survival [PFS]). For harms, data were extracted on non-relapse mortality (NRM) and relapse post-allografting. Our search strategy identified 240 studies, but only four studies (n = 72 patients) met our inclusion criteria. Pooled ORR, CR, OS, and PFS rates were 79%, 33%, 49%, and 30%, respectively. Pooled NRM and relapse rates were 24% and 28%, respectively. Results of this systematic review and meta-analysis indicate that allo-HCT yields encouraging OS in RS, thus remaining a reasonable treatment option in fit patients whose disease demonstrates a chemosensitive response to pre-transplant salvage therapies. Novel strategies are certainly needed to reduce the risk of relapse to further improve outcomes in these patients.

Complexities in the diagnosis of large B-cell lymphomas, classic Hodgkin lymphomas and overlapping peripheral T-cell lymphomas simplified: An evidence-based guide

The diagnosis of a large B-cell lymphoma and classic Hodgkin lymphoma (CHL) is often straightforward. However, in select circumstances, these simple diagnoses can be quite complex. In part, diagnostic difficulty may be due to uncertainty in the evaluation of morphologic and immunophenotypic features along a biologic continuum, or alternatively arise from uncertainty in predicting the behavior and outcomes of patients. Here, we systematically discuss and review areas of diagnostic difficulty in the diagnosis of large B-cell lymphomas (LBCL), classic Hodgkin lymphomas (CHL) and peripheral T-cell lymphomas (PTCL). We provide careful data-driven analyses and evidence-based approaches to help guide pathologists and clinicians. We discuss: 1) marginal zone lymphomas with increased large cells versus diffuse large B-cell lymphoma (DLBCL), 2) chronic lymphocytic leukemia with expanded proliferation centers versus diffuse large B-cell lymphoma (DLBCL), 3) chronic lymphocytic leukemia with Hodgkin/Reed-Sternberg-like cells versus CHL arising from chronic lymphocytic leukemia, 4) complex cases of follicular lymphoma versus DLBCL, 5) PTCL with large B-cell proliferations versus PTCL with LBCL, 6) PTCL with Hodgkin/Reed-Sternberg-like cells versus CHL, and finally 7) blastoid/pleomorphic mantle cell lymphoma versus DLBCL. Our evidence and data driven approach may serve as a useful diagnostic guide.

A case of T-cell chronic lymphocytic leukemia progressing to Richter syndrome with central nervous system involvement in a dog

An 8-year-old neutered Beagle dog was presented with polyuria and polydipsia. Routine clinicopathologic testing showed a significant lymphocytosis and proteinuria. Lymphocytes were of small to intermediate in size with a mature morphology. Infectious disease screening was negative. PCR for antigen receptor gene rearrangements showed a clonal T-cell receptor (TCR) rearrangement consistent with T-cell chronic lymphocytic leukemia (CLL). Bone marrow cytology showed <30% lymphocytes, while the proportion in splenic fine-needle aspirate cytology was considered increased. The dog was initially monitored but started on prednisolone and chlorambucil therapy 2 months later due to worsening clinical signs and progressive lymphocytosis. After an additional 2 weeks, the dog developed multifocal spinal pain and single-node lymphadenomegaly. Cytology of the lymph node showed a monomorphic population of large lymphoblasts consistent with lymphoma. Cytology of a cerebrospinal fluid sample also showed large lymphoblasts. PCR for antigen receptor gene rearrangement at both sites showed a clonal TCR rearrangement of the same molecular size as in the initial leukemic cells. The dog was diagnosed with a transformation of the CLL to Richter syndrome (RS) with involvement of the central nervous system (CNS). Therapy was started with L-asparaginase and an increased dose of prednisolone; however, the dog was euthanized due to progressive clinical signs. To our knowledge, this is the first report of canine RS with direct involvement of the CNS.

Leukemic Involvement in the Thorax

Leukemias are malignancies in which abnormal white blood cells are produced in the bone marrow, resulting in compromise of normal bone marrow hematopoiesis and subsequent cytopenias. Leukemias are classified as myeloid or lymphoid depending on the type of abnormal cells produced and as acute or chronic according to cellular maturity. The four major types of leukemia are acute myeloid leukemia, chronic myeloid leukemia, acute lymphoblastic leukemia, and chronic lymphocytic leukemia. Clinical manifestations are due to either bone marrow suppression (anemia, thrombocytopenia, or neutropenia) or leukemic organ infiltration. Imaging manifestations of leukemia in the thorax are myriad. While lymphadenopathy is the most common manifestation of intrathoracic leukemia, leukemia may also involve the lungs, pleura, heart, and bones and soft tissues. Myeloid sarcomas occur in 5%-7% of patients with acute myeloid leukemia and represent masses of myeloid blast cells in an extramedullary location. ^©RSNA, 2019.

Richter's syndrome of T-cell lineage (T rex lymphoma)

By definition, Richter's syndrome represents the transformation of low-grade B-cell lymphoma into high-grade B-cell lymphoma, usually refractory to treatment. Exceptional cases of transformation into very aggressive mature T-cell lymphomas have been described as an unusual manifestation of the syndrome in patients died after few months from the diagnosis, despite chemotherapy. The time is ripe to regroup these T lymphomas under a new pathological subset, through the unequivocal alternate naming of 'T rex lymphoma', by analogy with the aggressive behavior of the famous dinosaur (T. rex). In practice, it represents the transformation of low-grade B-cell lymphoma into high-grade T-cell lymphoma, burdened by a very poor prognosis, because of the underlying B-cell lymphoma, which negatively interferes with the immune response of the patient. Against this distinct lymphomatous T clone, the major therapeutic efforts should be addressed.

Interaction between miRNAs and signaling cascades of Wnt pathway in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL), a severe problem all over the world and represents around 25% of all total leukemia cases, is generating the need for novel targets against CLL. Wnt signaling cascade regulates cell proliferation, differentiation, and cell death processes. Thus, any alteration of the Wnt signaling pathway protein cascade might develop into various types of cancers, either by upregulation or downregulation of the Wnt signaling pathway protein components. In addition, it is reported that activation of the Wnt signaling pathway is associated with the transcriptional activation of microRNAs (miRNAs) by binding to its promoter region, suggesting feedback regulation. Considering the protein regulatory functions of various miRNAs, they can be approached therapeutically as modulatory targets for protein components of the Wnt signaling pathway. In this article, we have discussed the potential role of miRNAs in the regulation of Wnt signaling pathway proteins related to the pathogenesis of CLL via crosstalk between miRNAs and Wnt signaling pathway proteins. This might provide a clear insight into the Wnt protein regulatory function of various miRNAs and provide a better understanding of developing advanced and promising therapeutic approaches against CLL.

Richter's transformation in patients with chronic lymphocytic leukaemia: a Nationwide Epidemiological Study

Richter's transformation (RT) refers to the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL). Approximately, 2-10% of patients with CLL develop RT, most often as diffuse large B-cell lymphoma. To assess the incidence of RT, we examined risk factors for RT and death among patients with RT in a nationwide CLL cohort (from 2008 to 2016). Among 3772 patients, 113 had biopsy-proven RT. With a median follow-up of 4.3 years, the 5-year cumulative incidence of RT was 2.8%. Advanced Binet stage (B/C) (p<.001), unmutated IGHV (p<.001), and del(17p) (p<.001) were independently associated with risk of developing RT. Half of the patients with RT (49%) were treatment-naïve prior to transformation and demonstrated longer survival after RT compared to patients previously treated for CLL (6.1 vs. 2.8 years, p=.03). Whether this finding could be explained by a higher proportion of clonally unrelated RT among treatment-naïve patients, remain to be addressed.

Tumor Lysis Syndrome in Chronic Lymphocytic Leukemia: A Rare Case Report from Nephrology

Patient: Female, 89

Final Diagnosis: Tumor lysis syndrome (TLS)

Symptoms: Dyspnea

Medication: Steriods

Clinical Procedure: HD

Specialty: Nephrology

High-grade B-Cell lymphoma with MYC and BCL6 rearrangements associated with Richter transformation of chronic lymphocytic leukemia

Richter transformation (RT), or Richter syndrome, is defined as the transformation of chronic lymphocytic leukemia (CLL) to an aggressive B-cell lymphoma. The vast majority, up to 99%, transform into diffuse large B-cell lymphoma (DLBCL), with a small subset (<1%) becoming classical Hodgkin lymphoma. Approximately half of RT cases progress through a pathway involving dysregulation of C-MYC. High-grade B-cell lymphoma (HGBL) is a recent diagnostic category of aggressive B-cell lymphomas set forth in the updated 2017 WHO Classification of Hematopoietic and Lymphoid Tissues. HGBL with MYC and BCL2 and/or BCL6 rearrangements, formerly “double-hit” and “triple-hit” lymphomas, comprise the majority of HGBL cases. Patients with HGBL have a worse prognosis than those with diffuse large B-cell lymphoma. We present a case of RT with rearrangements of MYC and BCL6. To our knowledge, there are no reported cases of RT with a “double-hit” lymphoma genotype.

PD-1 Expression in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) and Large B-cell Richter Transformation (DLBCL-RT): A Characteristic Feature of DLBCL-RT and Potential Surrogate Marker for Clonal Relatedness

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a low-grade B-cell neoplasm and ∼2% to 9% patients develop an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (Richter transformation, DLBCL-RT). Programmed death-1 (PD-1) pathway plays a crucial role in tumor host immunity evasion and its blockade has emerged as an effective anti-cancer immunotherapy. PD-L1 and PD-1 expression has shown predictive value in anti-PD cancer immunotherapy; however, it has not been well documented in CLL/SLL and DLBCL-RT. We evaluated PD-1 and PD-L1 expression by immunohistochemistry in 39 CLL/SLL, 15 DLBCL-RT, and 26 other DLBCL. In CLL/SLL, neoplastic B-cell PD-1 expression was weak and restricted to prolymphocytes/paraimmunoblasts within proliferation centers (PCs) and accentuated PCs of all sizes. Neoplastic B-cell PD-1 expression was highly prevalent and demonstrated increased intensity in DLBCL-RT, but in contrast was only rarely seen in other DLBCL (12/15 vs. 1/26; P<0.0001). An excellent correlation (90% concordance) was observed between neoplastic B-cell PD-1 immunohistochemistry positivity and molecularly defined CLL/SLL clonal relatedness in DLBCL-RT. PD-L1 expression was observed on the neoplastic B cells in rare DLBCL-RT and other DLBCL cases (1/15 vs. 1/26; P>0.05) as well as background histiocytes and dendritic cells. Overall survival of DLBCL-RT was significantly inferior to that of the other DLBCL (median, 16.9 vs. 106.1 mo; P=0.002). Our findings suggest a biological continuum from prolymphocytes/paraimmunoblasts in CLL/SLL PCs to the neoplastic B-cells in DLBCL-RT. The characteristic PD-1 expression in DLBCL-RT makes it a potential surrogate marker for determining clonal relatedness to CLL/SLL, which may have important prognostic and therapeutic implications.

Mechanisms of Resistance to Targeted Therapies in Chronic Lymphocytic Leukemia

Even if treatment options for Chronic Lymphocytic Leukemia (CLL) patients have changed dramatically in the past few years, with the approval of targeted therapeutic agents, the disease remains incurable. Beside intrinsic genetic features characterizing the leukemic cell, signals coming from the microenvironment have a key role in promoting cell survival and in protecting CLL cells from the action of drugs. Consequently, the identification of previously unrecognized genetic lesions is important in risk-stratification of CLL patients and is progressively becoming a critical tool for choosing the best therapeutic strategy. Significant efforts have also been dedicated to define microenvironment-dependent mechanisms that sustain leukemic cells favoring survival, proliferation, and accumulation of additional genetic lesions. Furthermore, understanding the molecular and biological mechanisms, potentially driving disease progression and chemoresistance, is the first step to design therapies that could be effective in high-risk patients. Significant progress has been made in the identification of the different mechanisms through which patients relapse after "new" and "old" therapies. These studies have led to the development of targeted strategies to overcome, or even prevent, resistance through the design of novel agents or their combination.In this chapter we will give an overview of the main therapeutic options for CLL patients and review the mechanisms of resistance responsible for treatment failure. Potential strategies to overcome or prevent resistance will be also discussed.