Second primary malignancy after rituximab-containing immunochemotherapy for diffuse large B cell lymphoma.

Extended post-therapy long-term survival of patients with diffuse large B cell lymphoma (DLBCL) may also lead to an increase of late adverse events. We retrospectively investigated the frequency and clinical manifestation of second primary malignancy (SPM) after rituximab-containing immunochemotherapy in patients with DLBCL treated at seven institutes belonging to the Kyoto Clinical Hematology Study Group (KOTOSG) from the perspective of the existence of past or synchronous cancer history. In a median follow-up period of 899 days, 69 SPMs were observed in 58 of 809 patients. The most frequent SPM was gastric cancer, followed by lung cancer and colorectal cancer. The cumulative incidence of SPM increased steadily over time and was not significantly influenced by the presence or absence of past or synchronous cancer history. Our study suggests the need for careful attention to SPM in patients with DLBCL in daily practice.

Serine-227 in the N-terminal kinase domain of RSK2 is a potential therapeutic target for mantle cell lymphoma.

RSK2 is a serine/threonine kinase downstream signaling mediator in the RAS/ERK signaling pathway and may be a therapeutic target in mantle cell lymphoma (MCL), an almost incurable disease subtype of non-Hodgkin lymphoma. In this study, serine-227 (RSK2Ser227 ) in the N-terminal kinase domain (NTKD) of RSK2 was found to be ubiquitously active in five MCL-derived cell lines and in tumor tissues derived from five MCL patients. BI-D1870, an inhibitor specific to RSK2-NTKD, caused RSK2Ser227 dephosphorylation, and thereby, induced dose-dependent growth inhibition via G2 /M cell cycle blockade and apoptosis in four of the five cell lines, while one cell line showed only modest sensitivity. In addition, RSK2 gene knockdown caused growth inhibition in the four BI-D1870-sensitive cell lines. Comparative gene expression profiling of the MCL-derived cell lines showed that inhibition of RSK2Ser227 by BI-D1870 caused downregulation of oncogenes, such as c-MYC and MYB; anti-apoptosis genes, such as BCL2 and BCL2L1; genes for B cell development, including IKZF1, IKZF3, and PAX5; and genes constituting the B cell receptor signaling pathway, such as CD19, CD79B, and BLNK. These findings show that targeting of RSK2Ser227 enables concomitant blockade of pathways that are critically important in B cell tumorigenesis. In addition, we found favorable combinatory growth inhibitory effects of BI-D1870 with inhibitors of BTK (ibrutinib), AKT (ipatasertib), and BCL2 (venetoclax) in cell characteristic-dependent manners. These results provide a rationale for RSK2Ser227 in the NTKD as a potential therapeutic target in MCL and for future development of a novel bioavailable RSK2 NTKD-specific inhibitor.

Tumor-specific transcript variants of cyclin D1 in mantle cell lymphoma and multiple myeloma with chromosome 11q13 abnormalities.

Cyclin D1 (CCND1) overexpression is an early and unifying oncogenic event in mantle cell lymphoma (MCL) and multiple myeloma (MM) with chromosome 11q13 abnormalities. Herein, we report newly discovered transcript variants of the CCND1 gene in MCL and MM cells with chromosome 11q13 abnormalities. These transcript variants, designated CCND1.tv., covered the full-length coding region of CCND1 with longer 5'-untranslated regions (5'-UTRs) of CCND1 and occasionally contained a novel exon. CCND1.tv. was specifically detectable in patient-derived primary MCL or MM cells with chromosomal translocation t(11;14)(q13;q32), but not in t(11;14)-negative cells. The lengths of the 5'-UTR sequences of CCND1.tv. differed among patients and cell lines. Introduction of CCND1.tv. led to increased expression of normal-sized CCND1 protein in HEK293 cells. Furthermore, mTOR inhibition by rapamycin or serum starvation reduced ectopic expression of CCND1.tv.-derived CCND1 protein, but not 5'-UTR less CCND1-derived CCND1 protein in HEK293 cells, suggesting that the protein expression of CCND1.tv. is regulated by the mTOR pathway. Our results suggest that the aberrant expression of CCND1.tv. may contribute to the understanding of the pathogenesis of MCL and MM with 11q13 abnormalities.

Human herpesvirus-6 pneumonitis in a patient with follicular lymphoma following immunochemotherapy with rituximab.

Primary infection with human herpesvirus-6 (HHV-6) commonly occurs at an early age in children, most often at 3 years of age, and is associated with childhood diseases, such as exanthema subitum, hepatitis, febrile convulsions, or encephalitis. However, the virus occasionally reactivates from its latent state in immunosuppressed adults, especially post-transplant, resulting in serious disseminated, sometimes life-threatening end-organ complications. Herein, we report a case of a 68-year-old man with relapsed follicular lymphoma who developed HHV-6 pneumonitis. Eighteen months after achieving second complete remission by salvage immunochemotherapy with rituximab, the patient was complicated by pneumonia, with chest computed tomography finding showing disseminated nodular shadows with ground-glass opacity in both lungs. While empiric antibiotic and antifungal therapies did not improve the pneumonia, polymerase chain reaction-based viral screening tests on his bronchoalveolar lavage fluid detected the presence of HHV-6 DNA, and ganciclovir treatment quickly resolved the pneumonia, indicating that he suffered from HHV-6 pneumonitis. He had no other HHV-6-related end-organ damage, such as encephalitis. This case suggests that, although extremely rare, HHV-6 reactivation should be considered as one of the candidate pathogens for pulmonary complications of uncertain etiology in patients who have been treated with intensive immunosuppressive chemotherapy, even without hematopoietic stem cell transplantation. Furthermore, polymerase chain reaction-based viral screening testing on bronchoalveolar lavage fluid is a powerful diagnostic tool for pneumonitis due to viral reactivation, including HHV-6 reactivation.

Chromosomal abnormality variation detected by G-banding is associated with prognosis of diffuse large B-cell lymphoma treated by R-CHOP-based therapy.

Diffuse large B-cell lymphoma (DLBCL), which is the most prevalent disease subtype of non-Hodgkin lymphoma, is highly heterogeneous in terms of cytogenetic and molecular features. This study retrospectively investigated the clinical impact of G-banding-defined chromosomal abnormality on treatment outcomes of DLBCL in the era of rituximab-containing immunochemotherapy. Of 181 patients who were diagnosed with DLBCL and treated with R-CHOP or an R-CHOP-like regimen between January 2006 and April 2014, metaphase spreads were evaluable for G-banding in 120. In these 120 patients, 40 were found to harbor a single chromosomal aberration type; 63 showed chromosomal abnormality variations (CAVs), which are defined by the presence of different types of chromosomal abnormalities in G-banding, including 19 with two CAVs and 44 with ≥3 CAVs; and 17 had normal karyotypes. No specific chromosomal break point or numerical abnormality was associated with overall survival (OS) or progression-free survival (PFS), but the presence of ≥3 CAVs was significantly associated with inferior OS rates (hazard ratio (HR): 2.222, 95% confidence interval (CI): 1.056-4.677, P = 0.031) and tended to be associated with shorter PFS (HR: 1.796, 95% CI: 0.965-3.344, P = 0.061). In addition, ≥3 CAVs more frequently accumulated in high-risk patients, as defined by several conventional prognostic indices, such as the revised International Prognostic Index. In conclusion, our results suggest that the emergence of more CAVs, especially ≥3, based on chromosomal instability underlies the development of high-risk disease features and a poor prognosis in DLBCL.

Phosphoinositide-dependent protein kinase 1 is a potential novel therapeutic target in mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a relatively rare subtype of B-cell non-Hodgkin lymphoma (NHL) that has a poor prognosis despite recent advances in immunochemotherapy and molecular targeted therapeutics against NHL. Therefore, the development of a new therapeutic strategy for MCL is urgently needed. In this study, we show for the first time that 3-phosphoinositide-dependent protein kinase 1 (PDPK1), an oncogenic serine-threonine protein kinase, is commonly expressed in its phosphorylated active form in patient-derived tumor cells of various types of B-cell NHL cells, including diffuse large B-cell lymphoma, follicular lymphoma, and MCL. Blockade of PDPK1 activity by small-molecule inhibitors specific for PDPK1 (BX-912 and GSK2334470) or by RNA interference exerted antiproliferative effects in all four MCL-derived cell lines examined and these growth-inhibitory effects were mediated by both induction of apoptosis and G2/M cell cycle blockade. In addition, blockade of PDPK1 led to inactivation of its downstream effector kinase RSK2, but not AKT, suggesting the importance of the PDPK1/RSK2 signaling pathway in the proliferation and survival of MCL cells. Finally, when combined with anticancer agents, including genotoxic agents, a proteasome inhibitor, and a BH3 mimetic in vitro, the PDPK1 inhibitor BX-912 showed additive growth-inhibitory effects against MCL-derived cell lines in most settings. In particular, the combination of BX-912 and ABT-263, a BH3 mimetic, resulted in the enhancement of the induction of apoptosis. In conclusion, our results suggest that PDPK1 is a potential novel therapeutic target in MCL and indicate that clinical development of PDPK1-targeted therapy for MCL is desirable.

Burkitt Lymphoma Preceded by Autoimmune Hemolytic Anemia due to Anti-D Antibody.

We herein report a rare case of Burkitt lymphoma (BL) preceded by autoimmune hemolytic anemia (AIHA) caused by autoantibodies against D antigen. After a partial response to AIHA with prednisolone (PSL) treatment for 7 months, the patient developed BL with a t(8;22)(q24;q11.2) chromosomal translocation. Intensive immunochemotherapy, including rituximab, led to a complete response (CR) of BL; however, anti-D antibody remained detectable in the plasma and antibody-dissociated solution from erythrocytes, thus continuous therapy with PSL was necessary even after achievement of the CR. BL with AIHA is extremely rare, with only one previously reported case in the literature.

Diffuse large B-cell lymphoma presenting with central pontine myelinolysis: a case report.

INTRODUCTION: The most common cause of central pontine myelinolysis is an overly rapid correction of hyponatremia, although it can also occur in patients with any condition leading to nutritional or electrolyte stress. We report a case of diffuse large B-cell lymphoma with central pontine myelinolysis developing at the onset of disease. To the best of our knowledge, hematological malignancies presenting with central pontine myelinolysis have been rarely reported, especially in previously untreated patients, as in our case report. CASE PRESENTATION: A 78-year-old Japanese woman presented to a neighborhood clinic with persistent high fever, edema, and general weakness. Despite the absence of specific neurological findings, brain magnetic resonance imaging showed an abnormal lesion in the central pons area of her brain (hyperintense on T2-weighted and hypointense on T1-weighted sequences), compatible with central pontine myelinolysis. She was admitted to our emergency department in a state of shock one month later. The results of her blood tests showed greatly elevated C-reactive protein and lactate dehydrogenase levels. She had severe hypoalbuminemia and mild hyponatremia, and showed signs of disseminated intravascular coagulation. Mild bilateral pleural effusion, prominent subcutaneous edema, and splenomegaly were detected on her systemic computed tomography scan. Her body fluid cultures did not show signs of infection and her spinal aspiration did not show pleocytosis or abnormal cells. A diagnosis of diffuse large B-cell lymphoma was made based on the results of her bone marrow examination. As she was critically ill before the diagnosis was made, she was treated with methylprednisolone pulse therapy, followed by systemic chemotherapy (rituximab with modified THP-COP regimen, including cyclophosphamide, pirarubicin, vindesine, and prednisolone), which resulted in complete remission and recovery without any neurological defects, and resolution of her abnormal findings on magnetic resonance imaging. CONCLUSIONS: Central pontine myelinolysis is a serious condition that may result in neuropathological sequelae and mortality, and clinicians should be aware of its potential presence in patients with malignancies.