**Author details**

**Figure 12.** Mature miRNA does not unite to its target RNAm because it is blocked by a complementary therapeutic

The expression profile analysis for miRNAs in tumour cells has revealed that the deregulation of these molecules is frequent in a wide array of tumours. MiRNAs may act as tumour suppressants or oncoproteins, which regulate key routes involved in cell growth and apoptosis. Each miRNA may have hundreds of target genes, and several genes are targeted by several miRNAs: this creates a highly complex regulatory network. As we could appreciate in this revision, studies that analyse the expression profile for miRNAs in the different degrees of astrocytomas are scarce; therefore, it is convenient to include a greater number of cases, which helps define the expression profile characteristic for each degree: pilocytic, diffuse, anaplastic and GBM. Within the classing of astrocytic tumours, GBM is the most widely studied tumour, given the fact that it is the most common brain neoplasm in adults and it is quickly disseminated in the adjacent brain tissue, which makes its surgical resection impossible. In GBM, miRNAs participate in several cell processes such as cell proliferation, invasion, angiogenesis and differentiation. Different studies regarding the expression profile of miRNAs in GBM point to overexpressed miRNAs such as miR-10b, miR-21, miR-221 and miR-26 and less expressed miRNAs such as miR-124, miR-128, miR-137, miR-181, miR-7, miR-34 and miR-451. miR-21, miR-221, miR-124, miR-128, miR-181, miR-7 and miR-34 are the best characterised miRNAs with a potential to be used as tumour markers. Nevertheless, it is necessary to correlate the expression profile of miRNAs with clinical and pathological data to answer the

miRNA.

**13. Conclusions and future applications**

74 Glioma - Contemporary Diagnostic and Therapeutic Approaches

therapy or survival of patients.

Mario Perezpeña-Diazconti1 \*, Pilar Eguía-Aguilar2 and Fernando Chico Ponce de León3

\*Address all correspondence to: mpdiazconti@gmail.com

1 Department of Pathology, Hospital Infantil de México Federico Gómez, México City, Mexico

2 Molecular Biology Laboratory of the Department of Pathology, Hospital Infantil de México Federico Gómez, México City, Mexico

3 Department of Neurosurgery, Hospital Infantil de México Federico Gómez, México City, Mexico
