A team of researchers at Cardiff University has discovered stem cells in the cheek can be used to supress the immune system. It should help patients with certain types of diabetes, and those whose bodies reject organs after transplants.
It'll be several years before a treatment's developed but the scientists say it's a real breakthrough.
More top news
All primary and secondary schools in Wales have been categorised in a new colour-coded system. Is your school green or red?
A yellow warning for snow and ice on Thursday night and Friday has been issued.
Some wintry showers and staying windy with a significant wind chill and widespread frost developing