Clinical, histopathologic, and genetic features of pediatric primary myelofibrosis--an entity different from adults

Primary myelofibrosis is a chronic myeloproliferative neoplasm characterized by cytopenias, leukoerythroblastosis, extramedullary hematopoiesis, hepatosplenomegaly and bone marrow fibrosis. Primary myelofibrosis is a rare disorder in adults; children are even less commonly affected by this entity, with the largest pediatric case series reporting on three patients. Most literature suggests spontaneous resolution of myelofibrosis without long term complications in the majority of affected children. We describe the clinical, pathologic, and molecular characteristics and outcomes of nineteen children with primary myelofibrosis treated in our center from 1984 to 2011. Most patients had cytopenia significant enough to require supportive therapy. No child developed malignant transformation and only five of the 19 children (26%) had spontaneous resolution of disease. Sequence analyses for JAK2V617F and MPLW515L mutations were performed on bone marrow samples from 17 and six patients, respectively, and the results were negative. In conclusion, analysis of this large series of pediatric patients with primary myelofibrosis demonstrates distinct clinical, hematologic, bone marrow, and molecular features from adult patients.     

Benefit from autologous stem cell transplantation in primary refractory myeloma? Different outcomes in progressive versus stable disease

Background

Several studies of autologous stem cell transplantation in primary refractory myeloma have produced encouraging results. However, the outcome of primary refractory patients with stable disease has not been analyzed separately from the outcome of patients with progressive disease.

Design and Methods

In the Spanish Myeloma Group 2000 trial, 80 patients with primary refractory myeloma (49 with stable disease and 31 with progressive disease), i.e. who were refractory to initial chemotherapy, were scheduled for tandem transplants (double autologous transplant or a single autologous transplant followed by an allogeneic transplant). Patients with primary refractory disease included those who never achieved a minimal response (≥25% M-protein decrease) or better. Responses were assessed using the European Bone Marrow Transplant criteria.

Results

There were no significant differences in the rates of partial response or better between patients with stable or progressive disease. However, 38% of the patients with stable disease at the time of transplantation remained in a stable condition or achieved a minimal response after transplantation versus 7% in the group with progressive disease (P=0.0017) and the rate of early progression after transplantation was significantly higher among the group with progressive disease at the time of transplantation (22% versus 2%; P=0.0043). After a median follow-up of 6.6 years, the median survival after first transplant of the whole series was 2.3 years. Progression-free and overall survival from the first transplant were shorter in patients with progressive disease (0.6 versus 2.3 years, P=0.00004 and 1.1 versus 6 years, P=0.00002, respectively).

Conclusions

Our results show that patients with progressive refractory myeloma do not benefit from autologous transplantation, while patients with stable disease have an outcome comparable to those with chemosensitive disease. (ClinicalTrials.gov:{"type":"clinical-trial","attrs":{"text":"NCT00560053","term_id":"NCT00560053"}}NCT00560053)     

Melatonin interferes in the desmoplastic reaction in breast cancer by regulating cytokine production

Melatonin exerts oncostatic effects on breast cancer by interfering with the estrogen signaling pathways. Melatonin inhibits aromatase enzyme in breast cancer cells and fibroblasts. In addition, melatonin stimulates the adipogenic differentiation of fibroblasts. Our objective was to study whether melatonin interferes in the desmoplastic reaction by regulating some factors secreted by malignant cells, tumor necrosis factor (TNF)-α, interleukin (IL)-11, and interleukin (IL)-6. To accomplish this, we co-cultured 3T3-L1 cells with MCF-7 cells. The addition of breast cancer cells to the co-cultures inhibited the differentiation of 3T3-L1 preadipocytes to mature adipocytes, by reducing the intracytoplasmic triglyceride accumulation, an indicator of adipogenic differentiation, and also stimulated their aromatase activity. Melatonin counteracted the inhibitory effect on adipocyte differentiation and aromatase activity induced by MCF-7 cells in 3T3-L1 cells. The levels of cytokines in the co-culture media were 10 times those found in culture of 3T3-L1 cells alone. Melatonin decreased the concentrations of cytokines in the media and counteracted the stimulatory effect induced by MCF-7 cells on the cytokine levels. One millimolar melatonin induced a reduction in TNF-α, IL-6, and IL-11 mRNA expression in MCF-7 and 3T3-L1 cells. The findings suggest that melatonin may play a role in the desmoplastic reaction in breast cancer through a downregulatory action on the expression of antiadipogenic cytokines, which decrease the levels of these cytokines. Lower levels of cytokines stimulate the differentiation of fibroblasts and decrease both aromatase activity and expression, thereby reducing the number of estrogen-producing cells proximal to malignant cells.     

Melatonin promotes differentiation of 3T3-L1 fibroblasts

Melatonin inhibits the genesis and growth of breast cancer by interfering at different levels in the estrogen-signaling pathways. Melatonin inhibits aromatase activity and expression in human breast cancer cells, thus behaving as a selective estrogen enzyme modulator. As the adipose tissue adjacent to the tumor seems to account for most aromatase expression and enzyme activity in breast tumors and also mediates the desmoplastic reaction or accumulation of undifferentiated fibroblasts around malignant epithelial cells, in this work, we studied the effects of melatonin on the conversion of preadipocytes (3T3-L1) into adipocytes and on the capability of these cells to synthesize estrogens by regulating the expression and enzyme activity of aromatase, one of the main enzymes that participates in the synthesis of estrogens in the peritumoral adipose tissue. Thus, in both differentiating and differentiated 3T3-L1 adipocytes, high concentrations of melatonin increased intracytoplasmic triglyceride accumulation, an indicator of adipogenic differentiation. Melatonin (1 mm) significantly increased the expression of both CCAAT/enhancer-binding protein α and peroxisome proliferator-activated receptor γ, two main regulators of terminal adipogenesis, in 3T3-L1 cells. The presence of melatonin during differentiation also induced a parallel reduction in aromatase expression and activity and expression of the cells. The effects of melatonin were reversed by luzindole, a melatonin receptor antagonist, indicating that melatonin acts through known receptor-mediated mechanisms. These findings suggest that, in human breast tumors, melatonin could stimulate the differentiation of fibroblasts and reduce the aromatase activity and expression in both fibroblasts and adipocytes, thereby reducing the number of estrogen-producing cells proximal to malignant cells.     

Can 4-aminopyridine modulate dysfunctional gait networks in Parkinson's disease?

Gait dysfunction and postural instability represent a major therapeutic challenge in Parkinson's disease (PD). Gait disability in PD has been historically attributed to striato-nigral degeneration, however there is emerging evidence that multiple neurotransmitter deficits contribute to mobility impairment in PD. 4-aminopyridine (4-AP), a potent neurotransmitter modulator, has a wide range of favorable effects on gait in patients with neurological conditions including multiple sclerosis, spinal cord injury and cerebellar ataxia. In this Review we identify the neurobiological pathways involved in gait dysfunction in PD and discuss the mechanisms of action of 4-AP and its effect on gait related neuronal networks. The proposed mechanisms that may facilitate 4-AP favorable effect on gait in Parkinson's disease include 1) neurotransmitter release (dopamine, glutamate, acetylcholine and noradrenaline) 2) modulation of neuronal network oscillations and 3) increased cortical excitation. Recent clinical trials of 4-AP in neurological conditions associated with gait disorders will be highlighted and the importance of studying non-dopaminergic medications such as 4-AP in PD patients with gait impairment will be emphasized.