A cancer-fighting virus has shown some promise against a devastating childhood tumour of the eye.
Retinoblastomas are tumours of the developing retina that sometimes result in surgical removal of the eye. This cancer is often caused by mutations that alter a tumour-suppressing protein called RB1.
Angel Carcaboso of the Sant Joan de Déu Hospital in Barcelona, Spain, and his colleagues tested the effects of a genetically engineered virus that infects cancer cells that exhibit altered RB1 activity. The team cultured cells from 12 retinoblastoma samples and found that the virus infected and killed cells in 11 of these cultures. In mice grafted with human retinoblastoma cells, viral infection also blocked the cancer from spreading and delayed removal of the cancerous eye.
In the first two participants in a clinical trial of the treatment, the injected virus replicated in tumour cells but not in the healthy retina. In one patient, one dose shrank small tumours in the tissue in front of the retina; large retinal tumours in both patients were unchanged.