Identification of Loss of p16 Expression and Upregulation of MDR-1 as Genetic Events Resulting from Two Novel Chromosomal Translocations Found in a Plasmablastic Lymphoma of the Uterus

Plasmablastic lymphoma: current knowledge and future directions

Plasmablastic lymphoma (PBL) is an aggressive non-Hodgkin lymphoma associated with HIV infection and immunodeficiency. However, PBL can also be seen immunocompetent individuals in recent studies. PBL was characterized by distinct clinical and pathological features, such as plasmablastic morphology and universal expression of plasma cell markers. The clinicopathologic features were different between HIV-negative and HIV-positive patients. Gene expression analysis identified the unique molecular feature in PBL, including frequent c-MYC rearrangement and downregulation of BCR signaling pathway. Despite the recent advances in the treatment of PBL, the prognosis of PBL patients remains dismal. The objectives of this review are to summarize the current knowledge on the epidemiology, molecular profiles, clinical and pathological features, differential diagnosis, treatment strategies, prognostic factors, and potential novel therapeutic approaches in PBL patients.

An Atypical Presentation of an Uncommon Malignancy: Plasmablastic Lymphoma Presenting As Recurrent Scrotal Abscesses

Plasmablastic lymphoma (PBL) is a rare and extremely diagnostically challenging entity. We report a unique case of PBL in an adult male with a history of recurrent scrotal abscesses who presented with progressively worsening scrotal pain, swelling, and drainage. Pelvic CT demonstrated a large scrotal abscess with external draining tracts with foci of air. Surgical debridement revealed necrotic tissue throughout the abscess cavity, abscess wall, and scrotal skin. Immunohistochemical analysis of the scrotal skin specimen uncovered diffuse proliferation of plasmacytoid cells with immunoblastic features that stained positive for CD138, CD38, IRF4/MUM1, CD45, lambda restriction, and Epstein-Barr encoded RNA in situ hybridization (EBER-ISH) with high Ki-67 proliferation index greater than 90%. Taken together, these findings confirmed a diagnosis of PBL. Treatment with six cycles of infusional etoposide, prednisolone, vincristine, cyclophosphamide, and hydroxydaunorubicin (EPOCH-like regimen) was administered with subsequent positron emission tomography (PET)/CT confirmation of complete response. There was no clinical evidence of lymphoma recurrence at the time of follow-up six months later. Our case exemplifies the growing diversity of ways in which PBL may manifest and underscores the importance of a clinician's familiarity with this entity and its well-defined risk factor of immunosuppression.

Integrative genomic and transcriptomic analysis in plasmablastic lymphoma identifies disruption of key regulatory pathways

Plasmablastic lymphoma (PBL) represents a clinically heterogeneous subtype of aggressive B-cell non-Hodgkin lymphoma. Targeted-sequencing studies and a single-center whole-exome sequencing (WES) study in HIV-positive patients recently revealed several genes associated with PBL pathogenesis; however, the global mutational landscape and transcriptional profile of PBL remain elusive. To inform on disease-associated mutational drivers, mutational patterns, and perturbed pathways in HIV-positive and HIV-negative PBL, we performed WES and transcriptome sequencing (RNA-sequencing) of 33 PBL tumors. Integrative analysis of somatic mutations and gene expression profiles was performed to acquire insights into the divergent genotype-phenotype correlation in Epstein-Barr virus-positive (EBV+) and EBV- PBL. We describe a significant accumulation of mutations in the JAK signal transducer and transcription activator (OSMR, STAT3, PIM1, and SOCS1), as well as receptor tyrosine-kinase RAS (ERBB3, NRAS, PDGFRB, and NTRK) pathways. We provide further evidence of frequent perturbances of NF-κB signaling (NFKB2 and BTK). Induced pathways, identified by RNA-sequencing, closely resemble the mutational profile regarding alterations accentuated in interleukin-6/JAK/STAT signaling, NF-κB activity, and MYC signaling. Moreover, class I major histocompatibility complex-mediated antigen processing and cell cycle regulation were significantly affected by EBV status. An almost exclusive upregulation of phosphatidylinositol 3-kinase/AKT/mTOR signaling in EBV+ PBL and a significantly induced expression of NTRK3 in concert with recurrent oncogenic mutations in EBV- PBL hint at a specific therapeutically targetable mechanism in PBL subgroups. Our characterization of a mutational and transcriptomic landscape in PBL, distinct from that of diffuse large B-cell lymphoma and multiple myeloma, substantiates the pathobiological independence of PBL in the spectrum of B-cell malignancies and thereby refines the taxonomy for aggressive lymphomas.

HIV-negative plasmablastic lymphoma: report of 8 cases and a comprehensive review of 394 published cases

Background

Human immunodeficiency virus (HIV)-negative plasmablastic lymphoma (PBL) is a rare entity of diffuse large B-cell lymphoma (DLBCL). The clinicopathological features of and optimal treatment for HIV-negative PBL remain largely unknown.

Methods

To gain insight into this distinct lymphoma, we summarized the clinicopathologic characteristics of 8 unpublished HIV-negative PBLs and performed a comprehensive review of 394 published cases.

Results

Of the 8 unpublished PBLs, the median patient age was 53.0 years. Four patients presented with stage IV disease. All 8 patients showed a plasma cell-like immunophenotype. Of the six patients who received anthracycline-based chemotherapy, including two who received bortezomib, three patients achieved a continuous complete response, two patients died due to disease progression, and one patient was lost to follow-up. The other two patients achieved continuous complete response after receiving chemotherapy combined with radiotherapy and surgery. Of the 402 patients, the majority were male, with a mean age of 58.0 years. EBV infection was detected in 55.7% of the patients. The median survival times of the patients who received CHOP or CHOP-like regimens and intensive regimens were not reached and 23.0 months, respectively, and the intensive regimen did not improve the survival outcome (P=0.981). Multivariate analysis showed that EBER remained the only independent factor affecting overall survival (OS).

Conclusion

HIV-negative PBL is a distinct entity with a predilection for elderly and immunosuppressed individuals. Intensive chemotherapy had no apparent survival benefits over the CHOP regimen in terms of OS; the prognosis of this disease is poor with current chemotherapy methods, and treatment remains a challenge.

Interleukin-6-dependent growth in a newly established plasmablastic lymphoma cell line and its therapeutic targets

Plasmablastic lymphoma (PBL) is a rare, highly aggressive subtype of non-Hodgkin lymphoma with plasma-cell differentiation occurring typically in immune-suppressed patients such as those with AIDS. This study reports the establishment and characterization of a new cell line, PBL-1, derived from a patient with AIDS-associated PBL. Morphological assessment of PBL-1 indicated plasma-cell differentiation with a CD20(-) CD38(+) CD138(+) immunophenotype and IgH/c-myc translocation. The cell line harbours Epstein-Barr virus, but a 52.7-kbp length defect was identified in its genome, resulting in no expression of viral microRNAs encoded in the BamHI-A Rightward Transcript region. Importantly, supplementation of culture medium with >5 ng/mL of interleukin-6 (IL-6) was required for PBL-1 growth. Starvation of IL-6 or addition of tocilizumab, an inhibitory antibody for the IL-6 receptor, induced apoptosis of PBL-1. Transduction of IL-6 into PBL-1 by lentivirus vector induced autologous growth without IL-6 supplementation of culture medium. These data indicate the IL-6 dependency of PBL-1 for proliferation and survival. mTOR inhibitors induced cell death effectively, suggesting mTOR in the IL-6 signalling pathway is a potential therapeutic target for PBL. This established PBL cell line will be a useful tool to further understand the pathophysiology of PBL and aid the future development of PBL treatment.

Vitamin D Receptor Expression in Plasmablastic Lymphoma and Myeloma Cells Confers Susceptibility to Vitamin D

Plasmablastic B-cell malignancies include plasmablastic lymphoma and subsets of multiple myeloma and diffuse large B-cell lymphomaDLBCL. These diseases can be difficult to diagnose and treat, and they lack well-characterized cell line models. Here, immunophenotyping and FOXP1 expression profiling identified plasmablastic characteristics in DLBCL cell lines HLY-1 and SU-DHL-9, associated with CTNNAL1, HPGD, RORA, IGF1, and/or vitamin D receptor (VDR) transcription. We demonstrated VDR protein expression in primary plasmablastic tumor cells and confirmed in cell lines expression of both VDR and the metabolic enzyme CYP27B1, which catalyzes active vitamin D3 production. Although Vdr and Cyp27b1 transcription in normal B cells were activated by interleukin 4 (IL-4) and CD40 signaling, respectively, unstimulated malignant plasmablastic cells lacking IL-4 expressed both VDR and CYP27B1. Positive autoregulation evidenced intact VDR function in all plasmablastic lines, and inhibition of growth by active vitamin D3 was both dependent on MYC protein inhibition and could be enhanced by cotreatment with a synthetic ROR ligand SR-1078. Furthermore, a VDR polymorphism, FOK1, was associated with greater vitamin D3-dependent growth inhibition. In summary, HLY-1 provides an important model of strongly plasmablastic lymphoma, and disruption of VDR pathway activity may be of therapeutic benefit in both plasmablastic lymphoma and myeloma.

Human immunodeficiency virus-negative plasmablastic lymphoma: A case report and literature review

RATIONALE

Plasmablastic lymphoma (PBL) is a rare subtype of human immunodeficiency virus (HIV)-related non-Hodgkin's lymphoma that predominantly manifests in the oral cavity.

PATIENT CONCERNS

Three cases of HIV-negative PBL were reported.

DIAGNOSES

HIV-negative PBL INTERVENTIONS:: The patient had undergone chemotherapy.

OUTCOMES

Clinical outcomes were very poor in Cases 1 and 3; Case 2, whose diagnosis suggested no bone marrow involvement, is still alive.

LESSONS SUBSECTIONS

These cases served to broaden the reported clinical spectrum of HIV-negative PBL. Clinicians and pathologists need to be familiar with lymphoma in the identified extra-oral PBL variation and there levant differential diagnosis procedures for this particular disease.

Human immunodeficiency virus-negative plasmablastic lymphoma: a comprehensive analysis of 114 cases

Human immunodeficiency virus-negative plasmablastic lymphoma (PBL) is an extremely rare entity. Its clinicopathological features, optimal treatment strategy and prognostic factors remain obsure. An extensive search was performed in the English language literature within the Pubmed database using the key words: ‘plasmablastic lymphoma and human immunodeficiency virus-negative or immunocompetent’. Data from 114 patients from 52 articles were analyzed. The mean patient age at diagnosis was 58.90 years (range, 2–86). HIV-negative PBL showed a predilection for elderly individuals (patients older than 60 years, 56.14%) and affected more males than females (M:F, 2.29:1). Ann Arbor stage IV patients accounted for 39.22% while bone marrow involvement was less frequent (12.79%). The Ki-67 index was high with a mean expression of 83%. Epstein-Barr virus (EBV) infection was common being positive in 58.70% of the patients while herpesvirus-8 (HHV-8) infection was rare being positive in only 7.55% of the patients. Immunosuppression was noted in 28.16% of patients. The median overall survival (OS) was 19 months. The 1- and 2-year survival rates were 52.3 and 45.3%, respectively. Age, gender and primary site showed no strong relationship with OS while Immunosuppression, Ann Arbor stage IV and EBV negativity were able to predict a poorer OS. Either complete remission (CR) or partial remission (PR) was superior to the refractory group in OS (P<0.0001 and P=0.0066, respectively). For stage I patients, the application of radiotherapy did not improve the OS. In conclusion, HIV-negative PBL is a distinct entity likely occurring in elderly and immunosuppressed individuals. Immunosuppression status, Ann Arbor stage IV, EBV negativity and refractory to treatment are poor prognostic factors of OS in HIV-negative PBL.

Orbital plasmablastic lymphoma: a clinico-pathological correlation of a rare disease and review of literature

Ocular involvement by plasmablastic lymphoma is extremely rare with very few reports in the literature. Its morphological and immunological resemblance to plasma cell myeloma makes it a diagnostic challenge, while its clinical course, which is characterized by recurrence and death, makes therapy a challenge for clinicians. We present three cases of plasmablastic lymphoma, each of which has distinct clinicoradiological features, and we also review the literature on orbital plasmablastic lymphomas.

Proteasome-based mechanisms of intrinsic and acquired bortezomib resistance in non-small cell lung cancer

The proteasome inhibitor bortezomib, registered for Multiple Myeloma treatment, is currently explored for activity in solid tumors including non-small cell lung cancer (NSCLC). Here we studied the proteasome-based mechanisms underlying intrinsic and acquired bortezomib resistance in NSCLC cells. Various NSCLC cell lines displayed differential intrinsic sensitivities to bortezomib. High basal chymotrypsin- and caspase-like proteasome activities correlated with bortezomib resistance in these cells. Next, via stepwise selection, acquired bortezomib resistant cells were obtained with 8-70-fold increased resistance. Cross-resistance was found to proteasome inhibitors specifically targeting β-subunits, but not to the novel α-subunit-specific proteasome inhibitor (5AHQ). Consistently, bortezomib-resistant cells required higher bortezomib concentrations to induce G2/M arrest and apoptosis. Interestingly, bortezomib concentration-dependent caspase cleavage, Mcl-1 and NOXA accumulation remained intact in resistant H460 and SW1573 cells, while A549 resistant cells displayed different expression profiles suggesting additional and more protein specific adaptations. Furthermore, bortezomib-resistant cells exhibited increased levels of both constitutive and immuno-β-subunits. Sequence analysis of the bortezomib-binding pocket in the β5-subunit revealed Ala49Thr, Met45Val and Cys52Phe substitutions that were not previously described in solid tumors. Bortezomib-resistant cells displayed reduced catalytic proteasome activities and required higher bortezomib concentrations to achieve comparable inhibition of proteasome activity. Taken together, these findings establish that high basal levels of proteasome activity correlate with intrinsic bortezomib resistance. Furthermore, acquired bortezomib resistance in NSCLC is associated with proteasome subunit overexpression and emergence of mutant β5-subunits that likely compromise bortezomib binding. α-Subunit-specific proteasome inhibitors, however, can efficiently bypass this resistance modality.