Results: A high level of agreement (100 % correlation for formalin-fixed paraffin-embedded tissue and fine-needle aspirate samples and 93 % correlation for cyst fluid specimens) was obtained despite the use of different methodologies. Conclusion: Shift termination assay is a simple, robust, and sensitive method for the identification of KRAS mutations in wide variety of specimen types. Objective: MicroRNAs (miRs) are small RNAs that modulate protein expression via post-transcriptional regulation of mRNA. They are related to malignancy in several tumors. Deregulation of miRs expression has been described in high grade astrocytomas of adult patients, however there is scarce information in pediatric patients. In this work we quantified the expression profiles of miRs in pediatrics astrocytomas. Method: Total RNA was extracted from 59 astrocytomas and 8 normal brain (NB) tissues, formalin fixed paraffin embedded. The expression levels of miR-124, miR-128-1 and miR-221 were quantified by using miRNA-specific TaqMan miRNA assays.