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In recent years, endothelial progenitor cells (EPCs), gave rise to increasing interest because of their possible use as a therapeutic tool in the treatment of vascular lesions in ischemic tissues or as a target for anti neoplastic therapy. It has been shown that several drugs can increase the number of EPCs into the peripheral blood (PB). However, there is insufficient data concerning the mobilization and collection of EPCs during CD34+ cell mobilization. In this study, we have evaluated EPC mobilization and collection in a series of 47 patients affected by lymphoid neoplasms [31 non Hodgkin lymphoma and 16 multiple myeloma] undergoing CD34+ cell mobilization with cyclophosphamide (4000 mg/m2) and Filgrastim (5 microg/kg). PB EPCs identified by flow cytometry as CD34+/VEGFR2+/CD133+ cells showed a peak on day +10. This peak paralleled that of PB CD34+/CD45+ cells. A direct correlation was observed between CD34+ and CD34+/VEGFR2+/CD133+ cells (r = 0.99 P < 0.0001). An average of 23.7 x 10e6 CD34+/VEGFR2+ CD133+ cells have been collected (range 12.1-41.76 x 10e6). These findings showed that in hematological diseases, cyclophosphamide in combination with filgrastim allows the mobilization and collection of large numbers of EPCs which may be used for reparative medicine studies in these patients.

Accumulating evidence suggests that angiogenesis may play a key role in the pathogenesis of leukaemic disorders. Several studies have shown that bone marrow-derived endothelial cells (EC) may contribute to tumour angiogenesis and that in the peripheral blood of cancer patients there is an increased amount of circulating ECs (CECs) that may participate to new vessel formation. In this report, we showed that, in seven acute myeloid leukaemia (AML) patients with known cytogenetic abnormalities, CEC levels were significantly increased in comparison with controls and that a significant proportion of these CECs carried the same chromosomal aberration as blast cells (20-78%, mean value 42.1% of CECs). Most of CECs (mean value 74.4%) displayed immunophenotypic features of endothelial progenitor cells as they expressed CD133, a marker gradually lost during EC differentiation and absent on mature EC. These findings suggest a possible direct contribution of AML-related CECs to tumour vasculogenesis and possibly to the spreading and progression of the disease.

In multiple myeloma (MM), circulating endothelial cells (CECs) represent a vascular marker of angiogenesis and may reflect tumor mass. In this report, we showed that, in 5 MM patients with 13q14 deletion, CECs carried the same chromosome aberration as the neoplastic plasma cells (11%-32% of CECs with 13q14 deletion). Most of the CECs displayed immunophenotypic features of endothelial progenitor cells as they expressed CD133, a marker gradually lost during endothelial differentiation and absent on mature endothelial cells. To the contrary, in 3 patients with monoclonal gammopathy of undetermined significance and 13q14 deletion, CECs were cytogenetically normal and had a mature immunophenotype. In MM CECs, immunoglobulin genes were clonally rearranged. These findings suggest a possible origin of CECs from a common hemangioblast precursor that can give rise to both plasma cells and endothelial cells and point to a direct contribution of MM-derived CECs to tumor vasculogenesis and possibly to the spreading and progression of the disease.

Gemcitabine in combination with pegylated liposomal doxorubicin has been recognized as an effective treatment in patients with refractory solid tumors. To our knowledge, this is the first case of relapsed Hodgkin lymphoma with breast involvement successfully treated with this association.

Objective: Dendritic cells (DC) are central to the development of immune system responses. In a cohort of 54 patients affected by colorectal cancer, we prospectively investigated the number of peripheral blood (PB) DC type 1 (DC1) and type 2 (DC2) and correlated their counts and functionality to the stage of the disease and to vascular endothelial growth factor (VEGF) levels., Results: At diagnosis, compared with healthy controls, patients presented reduced PBDC1 and PBDC2 numbers (p < 0.001). Moreover, in cancer patients, PBDC showed low levels of DC-associated antigens (HLA DR, p = 0.004; CD11c, p < 0.001; CD83, p = 0.01; CD86, p = 0.007 and Mannose receptor, p = 0.029), an upregulation of CXCR4 (p = 0.017) and a reduced T cell stimulation capability (p < 0.001). DC1 and DC2 loss was higher in stage D versus stage ABC patients (p = 0.003 and p = 0.002, respectively); surgery and chemotherapy appeared to attenuate a DC defect, although the restoration of normal PBDC levels is completed only at 6 and 12 months after diagnosis, respectively. In this series of patients, PBDC1 and PBDC2 numbers inversely correlated with VEGF serum levels (p < 0.001), suggesting a possible effect of this cytokine on DC compartment. In culture, the exposure of monocyte-derived DC to VEGF produced a dramatic alteration of DC differentiation by (1) induction of apoptosis, (2) alteration of DC immunophenotypic profile and (3) increased CXCR4 expression. Exposure to anti-VEGF blocking antibodies reversed VEGF inhibitory effects in all cases., Conclusions: These findings suggest that in colorectal cancer patients there is a numerical and functional impairment of PBDC compartment possibly related to the stage of the disease and to VEGF levels., (Copyright (c) 2005 S. Karger AG, Basel.)

The in vivo effect of recombinant human erythropoietin (rHuEpo) and granulocyte colony-stimulating factor (G-CSF) combined treatment on CD34(+) cells was evaluated by fluorescence in situ hybridization (FISH) in 13 myelodysplastic syndrome (MDS) patients with known cytogenetic abnormalities. After treatment, responsive patients presented a significantly lower proportion of FISH abnormal CD34(+) cells than before treatment (P = 0.003), and in comparison with unresponsive cases (P = 0.007). Response to treatment was associated with a reduced degree of apoptosis in CD34(+) cells (P = 0.021): however, no difference in telomere length was observed in responsive patients after growth factor administration. Although the number of patients analysed was relatively small, the present data suggest that, in MDS patients, response to rHuEpo and G-CSF may be related to the proliferation of karyotypically normal but potentially defective CD34(+) progenitor cells.