Many microRNAs (miRNAs), posttranscriptional regulators of numerous cellular processes and developmental events, are downregulated in tumors. However, their role in tumorigenesis remains largely unknown. In this work, we examined the role of the muscle-specific miRNAs miR-1 and miR-206 in human rhabdomyosarcoma (RMS), a soft tissue sarcoma thought to arise from skeletal muscle progenitors. We have shown that miR-1 was barely detectable in primary RMS of both the embryonal and alveolar subtypes and that both miR-1 and miR-206 failed to be induced in RMS cell lines upon serum deprivation. Moreover, reexpression of miR-206 in RMS cells promoted myogenic differentiation and blocked tumor growth in xenografted mice by switching the global mRNA expression profile to one that resembled mature muscle. Finally, we showed that the product of the MET proto-oncogene, the Met tyrosine-kinase receptor, which is overexpressed in RMS and has been implicated in RMS pathogenesis, was downregulated in murine satellite cells by miR-206 at the onset of normal myogenesis. Thus, failure of posttranscriptional modulation may underlie Met overexpression in RMS and other types of cancer. We propose that tissue-specific miRNAs such as miR-1 and miR-206, given their ability to modulate hundreds of transcripts and to act as nontoxic differentiating agents, may override the genomic heterogeneity of solid tumors and ultimately hold greater therapeutic potential than single gene-directed drugs.

IFO added to MTX, CDP, and ADM from the preoperative phase does not improve the good responder rate and increases hematologic toxicity. IFO should only be considered in patients who have a poor histologic response to MTX, CDP, and ADM.

US-guided CNB is safe and effective. US contrast medium depicts tumour vascular supply and identifies the representative area(s) for sampling. Sensitivity and specificity are also high in subgrouping and grading, including myxoid types. Discussion about biopsy is part of the essential multidisciplinary strategy for these tumours.

The purpose of the present study was to analyze the characteristics of infectious complications occurring during the first 100 days after bone marrow transplantation (BMT) in a cohort of 123 pediatric patients with hematological malignancies (n = 73), solid tumors (n = 32) and nonmalignant disorders (n = 18). Fifty-eight patients received allogeneic grafts, and 65 patients an autologous transplant. Fever developed in 107 (87%) children; 82% of infectious complications occurred during the neutropenic period. Documented infection developed in 33 (31%) patients, while 74 (69%) patients had possible infection (i.e. fever of unknown origin). The incidence of bacteremia was 21%, and gram-positive cocci were the predominant pathogens; non-bacteremic microbiologically documented infection developed in 6% of patients; clinically evident infection developed in 4% of subjects. The incidence of primary febrile episodes was not significantly different between autologous and allogeneic BMT (86% vs 88%); nor did the median number of days to the onset of fever (5 days in both groups) or the median duration of fever (5 days in both groups) differ. In contrast, the frequency of secondary febrile episodes was significantly higher (P = 0.0001) in allogeneic BMT recipients (40%) than in autologous recipients (15%). The mortality rate due to infections was 2/36 (5%) for matched sibling donor BMT, and 1/13 (8%) for matched unrelated donor BMT. No deaths occurred in the 65 patients who were autografted. Invasive fungal infections accounted for 2 of the 3 infectious deaths. In conclusion, the majority of children undergoing BMT experienced at least one infectious episode; allogeneic BMT recipients were at high risk of developing secondary febrile episodes, but the overall mortality rate due to infection in the first 100 days after transplantation was low.

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