Two series of xenograft passages originated from one patient with both the primary tumor and the metastatic tumor in the lung. Although all of the 34 passages were used in the aCGH study, only 14 out the 34 passages were available for the miRNA study H 89 (Table 1). These 14 passages represented original 5 xenograft series, including both early and advanced passages. The passage 0 that represented primary tumor and was available for four series of the xenografts was not, however, available for miRNA profiling. The EWS-FLI1 and EWS-FEV translocations were present in 4 and 1 of the primary tumors, respectively, and were retained in all xenografts. To select an optimum

control for any kind of expression analysis is generally considered a difficult task; we ended up with selleck inhibitor two human mesenchymal stem cell samples from different cell cultures for use as controls. Mesenchymal

stem cells have been utilized as control samples in many previous expression studies due to the convincing evidence that supports the mesenchymal stem cell origin of ES [13–15]. DNA microarray analysis, as well as functional studies, have revealed the relationship between ES and mesenchymal stem cells [16, 17] as well as between ES and endothelium, and fetal neural crest [18, 19], further sustaining the fact that, despite all the efforts, the origin of ES is still a matter of dispute.

Very likely ES derives from much undifferentiated cells. In our analysis, we used mesenchymal stem cell as the calibrator, medroxyprogesterone in analogy to other reports recently published [20, 21]. Table 1 Ewing sarcoma xenograft series, 6, originating from five patients Case No. (Nude) Xenograft Passage 488 (15) 1*, 2*, 4, 7*, 11, 14* 445 (22) 0, 1, 4, 11, 15, 22 451 (53) 0, 4, 11*, 15*, 18, 21* 455 (199) 0, 1, 5*, 11, 17, 25* 430 (PRI) (230) 0, 1*, 4, 9, 19* 430 (MET) (248) 1*, 4, 14*, 21, 30* Case number 430 has two xenograft passages originating from one patient in different status of tumor: PRI = Primary Tumor, MET = Lung Metastasis. Samples used in the miRNA study are marked with an asterisk. Xenograft passage number 0 refers to the corresponding primary patient sample The stem cells were obtained from human primary bone marrow-derived mesenchymal stem cells after informed patient consent; precisely, from bone marrow aspirates (iliac crest) of patients undergoing hip replacement surgery. Nucleated cells were placed in modified alpha-MEM media (Li StarFish) containing 20% fetal bovine serum (Cambrex Bioscience), 100 units/mL penicillin (Life Technologies), 100 mg/mL streptomycin (Life Technologies), and 2 mmol/L glutamax (Life Technologies). Confluent cells were harvested by trypsin/EDTA and seeded at 1:3 density.