Glioblastoma is the most common type of brain tumor among adults. It grows fast, spreads quickly and there is currently no cure. This is partly due to the blood-brain barrier - unlike blood vessels elsewhere in the body the brain has a tightly packed layer of cells that line vessels to protect against circulating toxins or pathogens that could cause brain infections. This barrier also blocks treatment, that would work elsewhere in the body, reaching tumors 

Emma Keeling speaks to Maria Castro who has developed a therapy that smuggles a drug into the brain, breaching the blood-brain barrier, to deliver an immune response that kills tumor cells.

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