Medulloblastoma is the most common and a highly malignant pediatric brain tumor located in the cerebellar region of the brain. Medulloblastomas have recently been shown to consist of four distinct molecular subgroups, viz., WNT, SHH, group 3, and group 4. MiR-206, a miRNA first identified as a myomiR due to its enriched expression in skeletal muscle was found to be expressed specifically in the cerebellum, the site of medulloblastoma occurrence.

"Medulloblastoma, a common pediatric malignant brain tumor consists of four molecular subgroups viz. WNT, SHH, Group 3 and Group 4. MiR-148a is over-expressed in the WNT subgroup tumors, which have the lowest incidence of metastasis and excellent survival among all medulloblastomas. MiR-148a was expressed either in a transient manner using a synthetic mimic or in a stable doxycycline inducible manner using a lentiviral vector in non-WNT medulloblastoma cell lines.

Glioblastoma (GBM) is the most common and highly aggressive primary malignant brain tumor. The intrinsic resistance of this brain tumor limits the efficacy of administered treatment like radiation therapy. In the present study, effect of miR-224 expression on growth characteristics of established GBM cell lines was analyzed. MiR-224 expression in the cell lines as well as in primary GBM tumor tissues was found to be low.

We have carried out microRNA profiling of medulloblastomas in parallel with genome-wide expression profiling of protein-coding genes that identified differential miRNA expression in the four molecular subgroups of medulloblastomas, with the most distinctive miRNA profile of WNT subgroup tumours. Differential expression of eleven miRNAs across the four subgroups was validated by real-time RT-PCR in a set of 103 medulloblastomas.

Genome wide expression profiling studies including our own study has demonstrated that medulloblastoma is comprised of 4 core molecular subgroups viz. WNT, SHH, Group 3 and Group 4. We have molecularly classified a set of 103 medulloblastomas from the Indian subcontinent. WNT, SHH, Group 3 and Group 4 accounted for 22 %, 29 %, 20 %% and 28 % of the tumor tissues respectively as against the reported incidences of 11%, 28%, 27% and 34% based on the meta-analysis of the medulloblastoma data from the American and European subcontinent.