Micro-RNA deletion in neuroblastoma: A possible alternative mechanism of MYCN overexpression

9052 Background: Micro-RNAs (miRNAs) are small noncoding RNAs of 18 to 25 nucleotides that regulate protein expression. The biological functions of miRNAs are not yet fully understood. miRNA genes were recently found to be abnormally expressed in several types of cancer. By negatively regulating proto-oncogenes, miRNAs could act as tumor suppressors and conversely, by inhibiting tumor suppressors function as oncogenes. Neuroblastoma (NB) is the most common solid tumor in children under 5 years of age. Major adverse prognostic factors include: age over 1 year, advanced stages, adrenal primary site, MYCN amplification, diploid or tetraploid DNA content (DI), and chromosomal aberrations - including 1p deletions. We studied a possible involvement of miRNAs in neuroblastoma. Methods: The cohort consisted of 72 patients: 65% of them were above 1 year of age, 72% with advanced stages, 33% of the patients progressed. Median follow up was 60 months (ranging 1–221). Genomic DNA from 72 tumors were analyzed for the ...