Spontaneous and cytokine-induced thrombocytopenia in myelodysplastic syndromes: serum thrombopoietin levels and bone marrow morphology. Scandinavian MDS Group, Sweden and Norway

Epoetin alfa for the treatment of myelodysplastic syndrome-related anemia: A review of clinical data, clinical guidelines, and treatment protocols

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, leading to hematopoietic precursor cell apoptosis and peripheral blood cytopenias. Anemia is the most frequently experienced cytopenia and is the main cause of MDS symptoms, with fatigue and dyspnea contributing to reduced quality of life and increased morbidity. As MDS disease course and prognosis is influenced by disease factors, prognostic scoring systems have been developed for MDS to aid clinical and therapeutic decisions following diagnosis. Erythropoiesis- stimulating agents (ESAs) have been used for many years to treat anemia in patients with lower-risk MDS without chromosomal abnormalities. The use of ESAs is recommended by international clinical practice guidelines, due to the large body of evidence demonstrating their effectiveness in lower-risk MDS. In March 2017, the European Medicines Agency approved epoetin alfa for the treatment of anemia in lower-risk MDS patients, based on the results from a Phase 3 clinical trial and three European registry studies. The effectiveness of biosimilar epoetin alfa (Binocrit^®, Sandoz) to correct anemia in lower-risk MDS patients has also been demonstrated in a retrospective, single-center, observational study. The recent approval of epoetin alfa by the EMA in this setting will provide clinicians with a welcome, approved treatment option for lower-risk MDS.

Hyaluronan inhibits postchemotherapy tumor regrowth in a colon carcinoma xenograft model

Bone marrow hypoplasia and pancytopenia are among the most undesirable sequelae of chemotherapy for the treatment of cancer. We recently showed that hyaluronan (HA) facilitates hematopoietic recovery in tumor-free animals receiving chemotherapeutic agents. However, following a chemotherapeutic regimen in tumor-bearing animals, it is possible that residual tumor cells might respond to systemic injections of HA. Thus, in this study, we investigated the effect of HA on the regrowth of residual tumor cells following chemotherapy. As a model, we used the HCT-8 human colon carcinoma cell line, which expresses the HA receptor CD44, binds exogenous HA, and is susceptible to a chemotherapy protocol containing irinotecan and 5-fluorouracil in a human/mouse xenograft model. HCT-8 cells were implanted in severe combined immunodeficient mice, followed by irinotecan/5-fluorouracil treatment. After three rounds of chemotherapy, residual tumors were allowed to regrow in the presence or absence of HA. The dynamics of tumor regrowth in the group treated with HA was slower compared with the control group. By week 5 after tumor implantation, the difference in the size of regrown tumors was statistically significant and correlated with lower proliferation and higher apoptosis in HA-treated tumors as compared with controls. This finding provides evidence that HA treatment does not stimulate but delays the growth of residual cancer cells, which is an important parameter in establishing whether the use of HA can enhance current chemotherapeutic strategies.

A list of candidate cancer biomarkers for targeted proteomics

We have compiled from literature and other sources a list of 1261 proteins believed to be differentially expressed in human cancer. These proteins, only some of which have been detected in plasma to date, represent a population of candidate plasma biomarkers that could be useful in early cancer detection and monitoring given sufficiently sensitive specific assays. We have begun to prioritize these markers for future validation by frequency of literature citations, both total and as a function of time. The candidates include proteins involved in oncogenesis, angiogenesis, development, differentiation, proliferation, apoptosis, hematopoiesis, immune and hormonal responses, cell signaling, nucleotide function, hydrolysis, cellular homing, cell cycle and structure, the acute phase response and hormonal control. Many have been detected in studies of tissue or nuclear components; nevertheless we hypothesize that most if not all should be present in plasma at some level. Of the 1261 candidates only 9 have been approved as "tumor associated antigens" by the FDA. We propose that systematic collection and large-scale validation of candidate biomarkers would fill the gap currently existing between basic research and clinical use of advanced diagnostics.

Angiogenesis in relation to clinical stage, apoptosis and prognostic score in myelodysplastic syndromes

The International Prognostic Scoring System (IPSS), based on the number of cytopenias, percentage of bone marrow blasts and cytogenetics, is an important prognostic tool for patients with myelodysplastic syndrome (MDS). In addition, factors such as high bone marrow cellularity and lactate dehydrogenase levels have been associated with an adverse outcome, spontaneously and after chemotherapy. Recently, increased bone marrow angiogenesis, measured as, e.g. microvascular density (MVD), was reported to be more intense in high-risk than in low-risk MDS. To assess the prognostic role of MVD in MDS, a cohort of 56 patients, thoroughly investigated for various clinical and morphological parameters, were followed-up for survival > or =60 months after the diagnostic analysis. As a group MDS patients had higher MVD compared to healthy controls (p<0.02). The highest median MVD value was observed in the RAEB group, but there was no overall significant difference between the FAB groups. No significant correlations were observed between MVD and peripheral blood counts, bone marrow cellularity, percentage of bone marrow blasts and CD34 positive cells, apoptotic index (TUNEL), proliferation index (MIB-1), erythroid index, FAB group and IPSS score. MVD was not correlated to overall survival. In contrast, bone marrow blast count <5%, low or normal cellularity, as well as a high erythroid index, indicated a favorable survival. Thus, our data do not support an important prognostic role of angiogenesis, reflected by microvessel density, in the myelodysplastic syndromes.

The effects of 5-aza-2′-deoxycytidine (Decitabine) on the platelet count in patients with intermediate and high-risk myelodysplastic syndromes

5-Aza-2'-deoxycytidine, a DNA-hypomethylating agent, can induce clinical remissions in patients with high-risk myelodysplastic syndromes (MDS). During treatment an increase in platelet count is frequently the first positive event to be seen. In this study, we analyzed the platelet response of patients with high-risk MDS on low-dose 5-aza-2'-deoxycytidine therapy. We evaluated 162 from the 170 patients entered in three consecutive Phase II studies. One hundred twenty-six of them were thrombocytopenic at start of the therapy. All patients had an IPSS risk score of Intermediate I or higher. A rise in platelet count preceded a good trilineage response. In 58% of the thrombocytopenic patients a platelet response was already seen after one cycle of therapy. During therapy 69% of the patients with a low platelet count showed a response. Due to disease progression the final response rate was 63% in thrombocytopenic patients. No correlation was found between the platelet response and either the presence or absence of an adequate number of megakaryocytes or serum thrombopoietin levels. However, platelet response strongly predicted for overall survival (P < 0.0001). 5-Aza-2'-deoxycytidine has a clinically significant, often long lasting, effect on the platelet count in a substantial number of high-risk MDS patients.

The myelodysplastic syndrome(s): a perspective and review highlighting current controversies

The myelodysplastic syndrome (MDS) includes a diverse group of clonal and potentially malignant bone marrow disorders characterized by ineffective and inadequate hematopoiesis. The presumed source of MDS is a genetically injured early marrow progenitor cell or pluripotential hematopoietic stem cell. The blood dyscrasias that fall under the broad diagnostic rubric of MDS appear to be quite heterogeneous, which has made it very difficult to construct a coherent, universally applicable MDS classification scheme. A recent re-classification proposal sponsored by the World Health Organization (WHO) has engendered considerable controversy. Although the precise incidence of MDS is uncertain, it has become clear that MDS is at least as common as acute myelogenous leukemia (AML). There is considerable overlap between these two conditions, and the former often segues into the latter; indeed, the distinction between AML and MDS can be murky, and some have argued that the current definitions are arbitrary. Despite the discovery of several tantalizing pathophysiological clues, the basic biology of MDS is incompletely understood. Treatment at present is generally frustrating and ineffective, and except for the small subset of patients who exhibit mild marrow dysfunction and low-risk cytogenetic lesions, the overall prognosis remains rather grim. In this narrative review, we highlight recent developments and controversies within the context of current knowledge about this mysterious and fascinating cluster of bone marrow failure states.

Measurement of thrombopoietic levels: clinical and biological relationships

Platelet production is primarily regulated by the thrombopoietic cytokine thrombopoietin (TPO). In most cases thrombopoietin serum levels are determined by the rate of c-mpl receptor-mediated degradation after TPO uptake into platelets and megakaryocytes. The contribution of increased TPO protein synthesis by a translational mechanism was recently appreciated as the cause for hereditary thrombocythemia and will have to be elucidated in other conditions of thrombocytosis in association with increased TPO levels.