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Background During the course of COVID-19, the disease caused by the new coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), thrombotic phenomena and/or diffuse vascular damage are frequent, and viral elements have been observed within endothelial cells. Objectives CD146 + circulating endothelial cells (CD146 + CECs) and their progenitors (CEPs) are increased in cardiovascular, thrombotic, infectious, and cancer diseases. The present study was designed to investigate their kinetics in novel coronavirus (COVID-19) patients. Methods We used a validated flow cytometry procedure to enumerate viable and apoptotic CD146 + CECs and CEPs in COVID-19 patients during the course of the disease and in patients who recovered. Results Viable CEPs per milliliter were significantly increased in COVID-19 patients compared with healthy controls. This increase was observed in patients with mild symptoms and not further augmented in patients with severe symptoms. In patients who recovered, CEPs decreased, but were in a range still significantly higher than normal controls. Regarding mature CD146 + CECs, in COVID-19 patients, their absolute number was similar to those observed in healthy controls, but the viable/apoptotic CD146 + CEC ratio was significantly different. Both mild and severe COVID-19 patients had significantly less apoptotic CD146 + CECs compared with healthy controls. Patients who recovered had significantly less CD146 + CECs per milliliter when compared with controls as well as to mild and severe COVID-19 patients. A positive correlation was found between the copies of SARS-CoV-2 RNA in the cellular fraction and apoptotic CEPs per milliliter in severe COVID-19 patients. Conclusions CD146 + CECs and CEPs might be investigated as candidate biomarkers of endothelial damage in COVID-19 patients.

The role and regulation of innate immune cells is poorly understood in B-cell non-Hodgkin lymphoma (NHL). As natural killer (NK) cells, helper innate lymphoid cells (ILCs) are lymphocytes endowed with either anti- or pro-tumour activity and involved in inflammatory processes. In our ex vivo analysis of NK cells and ILCs from NHL patients, we observed that, in comparison to healthy donors (HD), the frequency of the cytotoxic subset of NK cells, the CD16

Background There is an urgent need for the identification of commonly assessable predictive factors in the treatment of patients with metastatic breast cancer. Methods During the course of a treatment including low dose metronomic oral cyclophosphamide and capecitabine plus i.v. bevacizumab (plus erlotinib in one third of the patients) for metastatic breast cancer, we observed that a relevant number of patients developed repeatedly elevated levels of mean corpuscular volume (MCV) of red blood cells without a significant fall in hemoglobin levels. We conducted a retrospective analysis on these 69 patients to evaluate if the increase in MCV could be associated to tumor response. Results During the course of treatment 42 out of 69 patients (61%) developed macrocytosis. Using Cox proportional hazards modeling that incorporated macrocytosis (MCV≥100 fl) as a time-dependent covariate, macrocytosis resulted in a halved risk of disease progression (HR 0.45; 95% CI, 0.22–0.92, p-value 0.028). In a landmark analysis limited to patients with no sign of progression after 24 weeks of treatment, median time to progression was 72 weeks (48 weeks after landmark) in patients who had developed macrocytosis, and 43 weeks (19 weeks after landmark) in patients who had not (p = 0.023). Conclusion Macrocytosis inversely related to risk of disease progression in patients treated with metronomic capecitabine plus cyclophosphamide and bevacizumab for metastatic breast cancer. This finding may be explained through thymidylate synthase inhibition by capecitabine. Whether bevacizumab has a role in determining macrocytosis, similarly to what happens with sunitinib, has to be further investigated. If other studies will confirm our findings, macrocytosis might be used as an early marker of response during metronomic treatment with capecitabine and cyclophosphamide with or without bevacizumab.

Circulating endothelial cells (CECs) and circulating endothelial progenitors (CEPs) are currently being investigated in a variety of diseases as markers of vascular turnover or damage and, also in the case of CEPs, vasculogenesis. CEPs appear to have a "catalytic" role in different steps of cancer progression and recurrence after therapy, and there are preclinical and clinical data suggesting that CEC enumeration might be useful to select and stratify patients who are candidates for anti-angiogenic treatments. In some types of cancer, CECs and CEPs might be one of the possible hidden identities of cancer stem cells. The definition of CEC and CEP phenotype and the standardization of CEC and CEP enumeration strategies are highly desirable goals in order to exploit these cells as reliable biomarkers in oncology clinical trials.

Medical oncologists are increasingly using anti-angiogenic drugs, but identifying the best-suited drug and the optimal dosage and schedule for treatment of patients remain challenging issues. Circulating endothelial cells (CECs) and circulating endothelial progenitors (CEPs) are modulated in a variety of diseases including cancer, and are promising surrogate biomarkers in oncology. Molecular surrogate markers, on the other hand, are more scanty at the present time, because the identification of truly endothelial cell-restricted genes and/or antigens is complex. Here, we discuss the biological and technical facets of the search and validation of new biomarkers for angiogenesis.

This review describes the current knowledge about cell subsets involved in vasculogenesis (i.e., differentiation of endothelial cells from mesodermal precursors) and angiogenesis (i.e., blood vessel generation from pre-existing vessels), together with recent findings about angiogenesis and antiangiogenic therapies in hematopoietic malignancies such as leukemia, lymphoma, myeloma, and myelodysplastic syndromes.

Cell fusion plays a well-recognized physiological role during development, while its function during progression is still unclear. Here, we show that acute myeloid leukemia (AML) cells spontaneously fused with murine host cells in vivo. AML cells fused in most cases with mouse macrophages. Other targets of AML cell fusion were dendritic and endothelial cells. Cytogenetic and molecular analysis revealed that successive recipients conserved detectable amounts of parental DNA. Moreover, in a mouse AML1-ETO model where female AML1-ETO-leukemic cells, expressing CD45.2, were injected in congenic CD45.1 male mice AML cells, we found hybrid cells expressing both allelic types of CD45 and XXY set of sexual chromosomes. More importantly, the fusion protein AML1-ETO was transferred in the hybrid cells. When sorted hybrid cells were reinjected in a secondary recipient, they gave rise to leukemia with 100% penetrance and similar time of onset of leukemic cells. Our data indicate that in vivo fusion of cancer cells with host cells may be a mechanism of gene transfer for cancer dissemination and suggest that fused cells may be used to identify still unrecognized leukemogenic genes that are conserved in hybrid cells and able to perpetuate leukemia in vivo.

Both chemotherapy and chimeric anti-CD20 monoclonal antibodies are effective agents against B-cell NHL. However, patients achieving remission are at risk of relapse. To evaluate the effect of the anti-angiogenic drug endostatin alone and after the administration of cyclophosphamide (CTX) or anti-CD20 rituximab antibody, we have generated a new model of human NHL by transplanting ip Namalwa cells in NOD/SCID mice. First, we evaluated the more effective treatment schedule of the different drugs. When administered alone, CTX (3 courses of 75 mg/Kg ip ) rituximab (3 courses of 25 mg/Kg ip ) and endostatin (5 courses of 50 μg sc ) delayed tumor growth, and CTX was the more effective in controlling bulky disease. When given after chemo- or immuno-therapy, endostatin effectively induced tumor stabilization. In fact, when mice given CTX or rituximab on day 3, 5 and 7 after transplantation were randomized to receive endostatin or PBS on day 15 to 19, in endostatin-treated mice tumor growth was prevented as long as the drug was administered. Furthermore, endostatin administered on day 25- to 29 after tumor re-growth was still able to induce significant tumor regression, whereas CTX and rituximab were not effective. Sequential administration of chemotherapy and endostatin seems promising for bulky NHL, and the less toxic sequential administration of rituximab and endostatin is promising for limited disease.