CAR-T therapy

T cells normally hunt infected or abnormal cells by reading surface proteins. CAR-T therapy reprograms them: a gene for a chimeric antigen receptor (CAR) is spliced in, giving the cell a new recognition head that locks onto a protein the tumour displays. The modified cells are expanded in a lab, then returned to the patient, where they seek and kill matching cells. The approach has produced durable remissions in blood cancers where other treatments failed. The hard parts are manufacturing (bespoke batches per patient are slow and expensive), toxicity (cytokine storms when the immune response overshoots), and solid tumours, where the target landscape is far messier.