A micro-engineered cancer treatment: cells upon cells.
(Science Week, day 3!)
Recently filed in the increasingly thick folder labelled "because of science, you don't necessarily have to die" is a story by James Gallagher for the BBC on a new cancer treatment which seems to have revived a girl from London, England after chemotherapy and a bone marrow transplant, no picnic for a young teenager, failed to expunge her leukaemia.
I'll just add the link and let you read the fortunate updates on Alyssa's recovery (hope you're still doing well out there, Alyssa), but take note of the diagrammed summary of the treatment's design. I wish my education permitted me to grasp the feat in finer detail, but it's clear enough that donated white blood cells were purposely modified to resist chemo and detect and attack the cancerous cells. In Alyssa's case, it was a variant of her own white blood cells which had mutated into the self-replicating cancer threat.
The BBC site also has a preceding story of a similar treatment.