13 January 2016 Last updated at 01:13 GMT
Lara Casalotti, from Hampstead, has Thai and Italian heritage.
She was diagnosed with blood cancer before Christmas and needs a stem cell transplant, but only 3% of donors on the register are currently mixed race.
BBC London's Alice Bhandukravi reports on a campaign that has gone global.
A student from London who has been diagnosed with leukaemia is appealing for more people from ethnic minority backgrounds to become stem cell donors.