Farnesyltransferase inhibitors in acute myeloid leukemia and myelodysplastic syndromes

Farnesyltransferase inhibitors were initially developed as Ras inhibitors as they inhibit the prenylation necessary for Ras activation. It is clear now that their mechanism of action is more complex and probably involves other proteins unrelated to Ras. At least 3 drugs within this family have been investigated in acute myeloid leukemia, myelodysplastic syndromes, and other leukemias. These are tipifarnib (R115777, Zarnestra), lonafarnib (SCH66336, Sarasar), and BMS-214662. The first 2 are administered orally, whereas BMS-214662 is given intravenously. These drugs are at different stages of development, and design of treatment schedules and methodology of the available studies are very different. Although most of the information is still preliminary, these agents have demonstrated clear evidence of clinical activity in these diseases and very favorable toxicity profiles. Several studies are still ongoing to better define the efficacy of these agents in the treatment of leukemias, as well as to determine the best schedules, the role of combination with other agents, and the role of these agents in different settings, such as the management of minimal residual disease. It is very possible that these agents will soon find their way to the ranks of established agents for the management of myeloid malignancies     

Cytolytic function and survival of natural killer cells are severely altered in myelodysplastic syndromes.

Natural Killer (NK) cells are critical in host defense against malignant transformation and are potent antileukemic cytotoxic effectors. In the present study, we investigated the peripheral NK function in patients with myelodysplastic syndromes (MDS). We demonstrated that the peripheral NK cell population was quantitatively normal in MDS patients. Furthermore, NK cells displayed an expression of the activating natural cytotoxicity receptors (NCR) NKp46 and NKp30 as well as NKG2D similar to that observed in donors, but exert a highly decreased constitutive cytolytic activity compared to resting normal NK cells. Although activation with IL-2 resulted in the upregulation of NKp46 expression by MDS-NK cells, their cytolytic function remained deeply altered as compared to activated donor NK cells. In addition, MDS NK cells did not proliferate in vitro, and displayed an increased rate of apoptosis in response to IL-2 stimulation although the spontaneous apoptosis was not significantly increased. Interestingly, a proportion of peripheral MDS-NK cells were derived from the MDS clone as the cytogenetic anomaly found in bone marrow karyotype was also detected in 20-50% of circulating NK cells. In conclusion, NK cells' cytolytic function and proliferative capacities in response to activation by cytokines are profoundly altered in MDS.     

Prevalence of N-ras mutations in children with myelodysplastic syndromes and acute myeloid leukemia.

The ras proto-oncogene family encodes a group of 21 kDa nucleotide-binding proteins. Activating mutations of ras genes are associated with certain types of malignancies, indicating that they are related in some way to the malignant process. We have examined bone marrow cells from nine children with myelodysplastic syndromes (MDS) and 35 with acute myeloid leukemia (AML) for activating point mutations of ras genes by in vitro amplification using polymerase chain reaction (PCR), oligonucleotide hybridization and sequencing of PCR products. We found N-ras mutations in cells from 3 of 9 children (33%) with MDS and only 2 of 35 children with AML (6%; 95% confidence interval is 0.7-19%). All mutations the second nucleotide of codon 12 or the first nucleotide of codon 61 of N-ras. There was no apparent correlation with clinical or laboratory characteristics, including karyotype; however, an association of N-ras activation with the most aggressive type of MDS was noted. Among the patients with MDS, 2 of 6 with monosomy 7 had N-ras mutations; however, three children with monosomy 7 which presented with AML lacked ras mutations. One patient was studied at time of diagnosis of MDS and again after progression to AML. At the preleukemic stage of disease, an N-ras mutation was identified; however, after development of AML this mutation was not present in the leukemic clone. In conclusion, these data show that ras mutations, while not necessary for leukemic transformation, may be important for the initiation of preleukemias evolving into overt AML.     

Immunologic abnormalities in myelodysplastic syndromes: clinical features and characteristics of the lymphoid population.

It has been recognized that some patients with myelodysplastic syndromes (MDS) develop immunologic abnormalities, but little is known of its correlations to MDS-specific disease features. In a retrospective study of 284 MDS patients, we identified 32 patients (11.3%) with clinical or serologic immunological abnormalities (group A) and compared them to the remaining 252 cases (group B). Group A consisted of 20 patients with clinical signs of autoimmune disease and 12 asymptomatic patients with serologic immunological abnormalities only. Apart from significant female predominance in group A (M/F = 2.5 vs M/F = 0.7, p = 0.001), the other clinical and biological features such as median age, distribution of MDS subtypes, incidence of karyotyopic abnormalities, "abnormal" in vitro growth of GM-progenitors and survival times were similar in the two groups. Autoimmune manifestations partially responded to immunosuppressive therapy, with moderate improvement of peripheral cytopenia. In addition, CD3+, CD4+, CD8+, CD19+, and CD56+ cells were quantified in peripheral blood of 38 patients. Matched with similarly aged healthy control group, most MDS patients showed significant lymphocytopenia, mainly due to the reduction of T-helper series (in both absolute numbers and percentage). B-cells were reduced in absolute numbers, but their percentage still overlapped with the control. No major abnormalities of natural killer cells (CD56+) were seen. We conclude that autoimmune diseases and asymptomatic immunologic abnormalities are common in patients with MDS, but except for female predominance, no correlation between these abnormalities and MDS-specific disease features were found.     

Hidden chromosomal aberrations are rare in primary myelodysplastic syndromes with evolution to acute myeloid leukaemia and normal cytogenetics

In myelodysplastic syndromes (MDS) a normal karyotype by cytogenetic analysis (CA) corresponds to a low cytogenetic risk for acute myeloid leukaemia (AML) evolution, a subset of patients however develops AML. We evaluated the use of interphase fluorescence in situ hybridisation (I-FISH) in 31 patients with evolution from primary MDS to AML and a normal CA at all stages of disease. Monosomy 7 was found in 4/31 cases, one patient had a terminal deletion 5q, each after AML evolution. The low frequency and unclear prognostic value of I-FISH anomalies in MDS related AML suggests that these alterations play a minor role for AML evolution.     

Endothelial precursors and mature endothelial cells are increased in the peripheral blood of myelodysplastic syndromes

Increased angiogenesis has been demonstrated to be a significant prognostic factor in many solid tumors. In the oncohematological setting, it has been associated with myelodysplastic syndromes (MDS), chronic myeloid leukemia, acute lymphoid, and myeloid leukemias. Recently, increased circulating endothelial cells (CECs) have been associated with breast cancer and non-Hodgkin lymphoma (NHL). Based on these premises we analysed total and activated CECs, and endothelial precursors (CEPs) in 50 MDS patients and 20 healthy donors. CECs and CEPs were quantified by flow cytometry. CEC levels were compared with bone marrow (BM) microvessel density (MVD). In addition, some angiogenic factors, namely vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) and soluble VEGF-Receptor2 (VEGFR2), were tested in the sera from 25 MDS patients. Total, activated CECs and CEPs were significantly increased in MDS when compared to control group (p<0.0001); whereas in the MDS cases no association was found with French--American--British (FAB), International Prognostic Scoring System (IPSS) subtypes or survival. Patients with higher CECs also showed higher MVD. Among the cytokines analysed, sVEGFR2 was significantly higher in the lower IPSS risk classes, while the levels of bFGF directly correlated with total and activated CECs. Taken together these data strengthen the hypothesis of a possible role of angiogenesis in MDS pathogenesis.     

Stathmin 1 is involved in the highly proliferative phenotype of high-risk myelodysplastic syndromes and acute leukemia cells

Stathmin 1 is an important cytoplasmic microtubule-destabilizing protein that plays critical roles in proliferation and accurate chromosome segregation through regulation of microtubule dynamics. High levels of Stathmin 1 expression have been reported in leukemia and solid tumors. However, Stathmin 1 has not been studied in myelodysplastic syndrome cells. We, herein, report that significantly higher Stathmin 1 levels were observed in proliferating hematopoietic cells, in high-risk MDS and acute leukemia cells. In addition, Stathmin 1 silencing in U937 and Namalwa leukemia cells reduced cell proliferation and clonogenicity. Our data suggest that Stathmin 1 expression may be related to the highly proliferative phenotype of hematopoietic cells and add new insights into the participation of Stathmin 1 in hematological malignancies.     

Experience in pediatric myelodysplastic syndromes.

Childhood MDS comprises a group of heterogeneous clinical disorders with overlapping features and many similarities to adult MDS. Environmental factors, genetic predisposition, certain viral infections, and impairment of the developing immune system perhaps play a major role in the genesis of the most common disease forms, such as JCMMoL and the monosomy 7 syndrome. One intriguing finding in these disorders is the striking male predominance. Diagnostic difficulties occur because dysplastic manifestations of the hematopoetic systems are usually not as impressive as in adults and because myelodysplastic and myeloproliferative disease forms overlap considerably. Despite these problems, we believe that pediatric cases of MDS should also be classified according to the established FAB classification for MDS. However, as has already been proposed earlier by others, JCMMol clearly should be considered as a specific entity different from the adult form of CMMoL. As has been shown by cell culture studies, JCMMoL is characterized by the presence of neoplastic macrophage/monocyte progenitor cells. These cells produce several factors that result in autostimulation and suppression of normal hematopoiesis. MDS is a highly malignant disease in children and evolves to acute leukemia after a short period. During the early phase of the disease, supportive care is sufficient. If a compatible donor is available, BMT is the treatment of choice and should be performed during the early stage of disease progression after clinical remission is obtained with chemotherapy. If BMT is not feasible, intensive chemotherapy may improve the clinical condition and prolong survival. Preliminary data suggest that the incorporation of hematopoietic growth and/or differentiation factors in chemotherapy and BMT protocols may have some beneficial effects. The only way to accumulate sufficient data on MDS in children with respect to clinical features, prognosis, and efficacy of treatment is to follow a uniform diagnostic and treatment program. To achieve substantial improvements in the management of childhood MDS, multicenter trials will be essential.     

Prognostic factors in myelodysplastic syndromes.

The extreme variability in prognosis among patients with myelodysplastic syndromes (MDS) complicates decision-making regarding their therapy. Several studies carried out in recent years have recognized the prognostic value of some clinical and biological characteristics. The percentage of blast cells in bone marrow, cytopenias, age and chromosome abnormalities are the most relevant factors affecting outcome. More importantly, some of these studies have resulted in the development of prognostic regression formulas and scoring systems for accurately estimating the individual prognosis of patients. The major aim of this review is to offer the clinician useful tools for treating MDS patients on a risk-fitted strategy.     

Epigenetic modifications of splicing factor genes in myelodysplastic syndromes and acute myeloid leukemia

Somatic mutations in splicing factor genes have frequently been reported in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Although aberrant epigenetic changes are frequently implicated in blood cancers, their direct role in suppressing one or both alleles of critical splicing factors has not been previously examined. Here, we examined promoter DNA hypermethylation of nine splicing factors, SF3B1, SRSF2, U2AF1, ZRSR2, SF3A1, HNRNPR, MATR3, ZFR, and YBX3 in 10 leukemic cell lines and 94 MDS or AML patient samples from the Australasian Leukemia and Lymphoma Group Tissue Bank. The only evidence of epigenetic effects was hypermethylation of the YBX3 promoter in U937 cells in conjunction with an enrichment of histone marks associated with gene silencing. In silico analysis of DNA methylation data for 173 AML samples generated by the Cancer Genome Atlas Research Network revealed promoter hypermethylation of the gene encoding Y box binding protein 3, YBX3, in 11/173 (6.4%) AML cases, which was significantly associated with reduced mRNA expression (P < 0.0001). Hypermethylation of the ZRSR2 promoter was also detected in 7/173 (4%) cases but was not associated with decreased mRNA expression (P = 0.1204). Hypermethylation was absent at the promoter of seven other splicing factor genes in all cell lines and patient samples examined. We conclude that DNA hypermethylation does not frequently silence splicing factors in MDS and AML. However, in the case of YBX3, promoter hypermethylation‐induced downregulation may contribute to the pathogenesis or maintenance of AML.     

NPM1 mutations in myelodysplastic syndromes and acute myeloid leukemia with normal karyotype

Mutations at exon 12 of the nucleophosmin (NPM1) gene are the most frequent acquired molecular abnormalities in adult and pediatric acute myeloid leukaemia (AML) with normal karyotype. We screened 28 patients with new diagnosed primary AML with normal karyotype, 38 patients with myelodysplastic symdromes (MDS) and 19 healthy volunteer for mutations at exon 12 of NPM1 gene. NPM1 mutations were identified in four AML patients and two MDS patients, including one novel sequence variant. As far as we know, this is the first report of NPM1 mutation in patients with MDS in the English literature until now, and our primary data support that NPM1 mutations may be also involved in the pathogenesis of MDS.     

Advance care planning in older patients with acute myeloid leukemia and myelodysplastic syndromes

IntroductionOlder patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) have worse survival rates compared to younger patients, and experience more intense inpatient healthcare at the end of life (EOL) compared to patients with solid tumors. Advance care planning (ACP) has been shown to limit aggressive and burdensome care at EOL for patients with AML and MDS. The purpose of this study was to better understand ACP from the perspective of clinicians, older patients with AML and MDS, and their caregivers.Materials and MethodsWe conducted semi-structured interviews with 45 study participants. Interviews were audio-recorded and transcribed. Open coding and focused content analysis were used to organize data and develop and contextualize categories and subcategories.ResultsGuided by our specific aims, we developed four themes: (1) The language of ACP and medical order for life-sustaining treatment (MOLST) does not resonate with patients, (2) There is no uniform consensus on when ACP is currently happening, (3) Oncology clinician-perceived barriers to ACP (e.g., patient discomfort, patient lack of knowledge, and lack of time), and (4) Patients felt that they are balancing fear and hope when navigating their AML or MDS diagnosis.DiscussionThe results of this study can be used to develop interventions to promote serious illness conversations for patients with AML and MDS and their caregivers to ensure that patient care aligns with patient values.     

Immunologic abnormalities in myelodysplastic syndromes.

In myelodysplastic syndromes, several autoimmune phenomena are more common than expected. Lymphocyte subsets are sometimes abnormal in number and function. Associated lymphoid malignancies and lymphoblastic evolution have occasionally been reported. Molecular studies suggest that the lymphoid system may be involved in the dysplastic process.     

Differentiation and hematopoietic-support of clonal cells in myelodysplastic syndromes

Studies were performed to obtain evidence of the differentiating and hematopoietic potential of marrow clone-original cells in patients with myelodysplastic syndromes (MDS). First, results of correlation analysis between bone marrow clonal cells and blast percentages for a total of 60 MDS showed that almost all cases had higher clonal (mean 50.1%) than blast proportion (mean 7.0%) (p < 0.001). In contrast, in 16 AML patients, mean clone/blasts disparity was nearly zero. Secondly, the amount of clone-original individual cells were defined in mature hematopoietic cells, mean 47.9% in segmented granulocytes, 47.1% in orthochromatic normoblasts and 37.8% in mature megakaryocytes. In addition, FISH examination showed approximately similar proportions of clonal cells in peripheral blood and marrow for all 22 tested cases (mean 39.1% in blood vs 49.8% in marrow). Moreover, the neutrophils in MDS peripheral blood oxidized dihydrorhodamine123 (DHR) nearly the same as neutrophils in a normal donor's circulation, while obviously poor function was observed in neutrophils from AML blood. Of note, research on clonality had an unexpected outcome as most of the typical morphological dysplastic cells possessed normal karyotypes. These findings lead to the proposal that the biological features of MDS clones are distinctive from those of AML clones.     

Thrombocytosis in myelodysplastic and myelodysplastic/myeloproliferative syndromes

Thrombocytosis at diagnosis is uncommon in myelodysplastic (MDS) and myelodysplastic/myeloproliferative (MDS/MPD) syndromes. We conducted a retrospective analysis to determine the clinical and haematopathological features of such patients, and the effect of thrombocytosis on prognosis. Of the 388 patients diagnosed with MDS from 1980 - 2006, 31 presented with thrombocytosis. The majority (71%) had low risk features and a low incidence of spontaneous bleeding or thrombo-embolic events. Compared to a case-matched control group of MDS and MDS/MPD patients without thrombocytosis of similar ages and IPSS scores, patients with thrombocytosis had a slightly lower probability of progression to a higher grade of MDS (P = 0.03), equivalent risk of transformation to acute myeloid leukemia (AML), and a trend (P = 0.07) towards longer overall survival (median 35.4 months compared to 27.6 months for controls).