Pathogenesis of Hodgkin's lymphoma

T-cell lymphoma in a Himalayan black bear in China

A 12-y-old Himalayan black bear suddenly developed depression, anorexia, cough, and dyspnea and died at the Ordos Zoo, China. At autopsy, the mesenteric and cranial mediastinal lymph nodes (LNs) were enlarged; the largest cranial mediastinal LN was ~13 cm in diameter. Scattered-to-diffuse, rounded-or-oval, gray, firm 1-6-mm nodules were observed on the surfaces of the spleen, liver, lungs, and small intestine. Histologically, the enlarged cranial mediastinal and mesenteric LNs, spleen, small intestine, lungs, and liver contained dense populations of neoplastic lymphoid cells (NLCs). The NLCs were round-or-oval with small amounts of mildly eosinophilic cytoplasm and round-or-oval hyperchromatic nuclei with indistinct nucleoli; the mitotic count was 55 in 2.37 mm2. Immunohistochemically, cell membranes and the cytoplasm of NLCs were CD3+, CD79a-, CD20-, CD15-, CD30-, and CD45RA-; hence, the NLCs were derived from T lymphocytes. To our knowledge, T-cell lymphoma has not been reported previously in a Himalayan black bear.

Macrophage Infiltration Correlates with Genomic Instability in Classic Hodgkin Lymphoma

Hodgkin lymphoma (HL) is a biologically diverse group of lymphoid tumors, which accounts for 1% of all de novo neoplasms in the world’s population. It is divided into two main groups: the more common classic Hodgkin lymphoma (cHL) and the less common nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). cHL is further divided into four subtypes, which differ in morphology and the contents of tumor microenvironment. Macrophages are one of the components of tumor microenvironment known to contribute to creating an immunosuppressive microenvironment, which inhibits the activity of cells expressing granzyme B against tumor cells, even when tumor cells are infected with Epstein–Barr virus (EBV). Our research aimed to explore the association between the specific contents of tumor microenvironment and the genetic anomalies in tumor cells. The presence and the relative percentage of cytotoxic T lymphocytes and macrophages was detected by immunohistochemical staining of the antigens specific for certain cell populations. Fluorescent in situ hybridization was used to detect anomalies in the genome of tumor cells and in situ hybridization was used to detect the presence of EBV. Our results show an association between the number of CD163+ macrophages and the number of TP53 copies or BCL6 gene translocation. Patients who had a higher number of CD163+ macrophages infiltrating tumor tissue and three or higher number of copies of TP53 showed poorer survival. We conclude that the presence of macrophages may contribute to genetic instability in cHL, which drives the progression of cHL and decreases survival of the patients.

Overview and outcome of Hodgkin's Lymphoma: Experience of a single developing country's oncology centre

Hodgkin's Lymphoma (HL) reveals variable epidemiological and clinico-pathological features in different geographical locations. In this retrospective study, we aimed to assess the epidemiological and clinic-pathological features, and outcome of HL patients treated at one hemato-oncology centre in Erbil, northern Iraq. Medical records of 103 HL patients treated over more than six years were reviewed. Treatment outcome was evaluated by measuring the 5-year overall and progression-free survival rates. The median age of patients was 23 years, children up to 17 years constituted 31.1%, and male to female ratio was 1:1.05. The majority (96.1%) of patients presented with lymphadenopathy. Nodular sclerosis subtype was the mostly encountered histologic type (48.5%); about half of the patients (49.5%) had stage II disease. Relapse occurred in 20 patients; the 5-year overall survival for children was better (89%) compared to adult patients (79%). The associated risk features found to have adverse effects on the survival, however, only high LDH level and presence of B-symptoms at presentation showed significant correlation. The epidemiological and clinical characteristics of HL in our locality followed the pattern in the western world. The 5-year overall and progression-free survivals were far below the international rates, a matter which may necessitate a revision to HL treatment strategy at our centre.

Hodgkin lymphoma in childhood: clinicopathological features and therapy outcome at 2 centers from a developing country

Hodgkin lymphoma (HL) accounts for 5% to 6% of all childhood cancer. It displays characteristic epidemiological, clinical, and pathological features according to various geographic areas. We aimed to assess the epidemiological aspects, clinicopathological features, and treatment outcome of pediatric HL treated at 2 Egyptian centers: Zagazig University Pediatric Oncology Unit and Benha Special Hospital Pediatric Oncology Unit. We carried a cross-sectional retrospective study by reviewing medical records for all patients admitted with the diagnosis of HL over 8 years in 2 oncology units during the period from January 2004 to January 2012. Age of the patients at presentation ranged from 3 to 14 years (median 6 years) and male: female ratio 1.7:1. Lymphadenopathy was the most common presentation (96.6%). Mixed cellularity subtype was dominant (50.8%), followed by nodular sclerosis (28.9%), lymphocyte-rich (18.6%) with lymphocyte depletion being the least dominant (1.7%). More than half of patients (55.9 %) had advanced disease (Ann Arbor stage III/IV disease). The duration of follow-up ranged from 5 to 87 months (mean 39.8 ± 24.1 months). The 5-year overall survival and event-free survival for patients were 96.6% and 84.7% respectively. In Egypt, HL occurs in young age group, with a higher incidence of mixed cellularity subtype and advanced disease. None of the clinical, epidemiological, or pathological characteristics had a significant association with the overall survival. The outcomes of HL in our 2 centers were satisfactory approaching the international percentage.

Hodgkin lymphoma: an update on its biology with new insights into classification

In the past few years, there has been a greater understanding of the spectrum and biology of Hodgkin lymphoma (HL). In standard texts, HL is classified as 2 distinct entities, namely nodular lymphocyte-predominant HL and classical HL (CHL). However, recent evidence suggests that CHL is not a single disease. Although the mixed cellularity and lymphocyte-depleted subtypes might be part of a biologic continuum, the nodular sclerosis subtype has a distinct epidemiology, clinical presentation, and histology. Nodular sclerosis HL might also be related to primary mediastinal B-cell lymphoma and mediastinal gray-zone lymphomas. We present an update on the pathobiology of HL and discuss these biologic and clinical differences in this review.

Hodgkin-lymphoma-derived cells show high sensitivity to dactinomycin and paclitaxel

Depending on stage and risk factors, up to 30% of patients with advanced Hodgkin lymphoma (HL) progress or relapse. Patients with pleural effusions have a particularly poor prognosis and this stage of HL is regularly resistant to chemotherapy. All currently available HL cell lines are derived from late stage HL patients. In the present study we measured the sensitivity of these HL lines against the 26 most frequently used cytostatic drugs. We used a novel fluorescent short-term survival assay where the cell was incubated with the drugs for 4 days. The precise number of differentially stained live and dead cells was determined using a custom-built automated laser confocal fluorescent microscope. We found that HL cells, independently of their origin, showed very similar sensitivity patterns for several of the drugs. All HL cell lines were highly sensitive to dactinomycin, paclitaxel and etoposide. Our data suggest that the inclusion of dactinomycin and paclitaxel into chemotherapy protocols against late stage Hodgkin lymphoma with pleural effusion may be justified.

The critical role of histology in an era of genomics and proteomics: a commentary and reflection

The role of histologic examination in lymphoma diagnosis has been called into question by proponents of new technologies, such as genomics and proteomics. We review the history and salient features of morphologic evaluation in lymphoid diseases, and discuss the general and specific limitations of mature ancillary techniques, such as immunohistochemistry, flow cytometry, and molecular studies. We then speculate on the future relationship between morphology and the new genomic and proteomic technologies as they become integrated into clinical practice.

Down-regulation of the TGF-beta target gene, PTPRK, by the Epstein-Barr virus encoded EBNA1 contributes to the growth and survival of Hodgkin lymphoma cells

The Epstein-Barr virus (EBV) contributes to the growth and survival of Hodgkin lymphoma (HL) cells. Here we report that down-regulation of the transforming growth factor-beta (TGF-beta) target gene, protein tyrosine phosphatase receptor kappa (PTPRK), followed EBV infection of HL cells and was also more frequently observed in the Hodgkin and Reed-Sternberg (HRS) cells of EBV-positive compared with EBV-negative primary HL. The viability and proliferation of EBV-positive HL cells was decreased by overexpression of PTPRK, but increased following the knockdown of PTPRK expression in EBV-negative HL cells, demonstrating that PTPRK is a functional tumor suppressor in HL. EBV suppressed the TGF-beta-mediated activation of PTPRK expression, suggesting disruption of TGF-beta signaling upstream of PTPRK. This was confirmed when we showed that the Epstein-Barr nuclear antigen-1 (EBNA1) decreased Smad2 protein levels and that this was responsible for PTPRK down-regulation. EBNA1 decreased the half-life of Smad2 but did not interact with Smad2. By down-regulating Smad2 protein expression, EBNA1 apparently disables TGF-beta signaling, which subsequently decreases transcription of the PTPRK tumor suppressor. We speculate that loss of the phosphatase function of PTPRK may activate as-yet-unidentified growth-promoting protein tyrosine kinases, which in turn contribute to the pathogenesis of EBV-positive HL.