Thousands of people have come forward following a worldwide appeal to find a stem cell donor for a Cardiff University student who needs a match in the next two months.
Vithiya Alphons, 24, has acute myeloid leukaemia but her Sri Lankan background makes the search hard as not many South Asian people are on donor registers.
She launched a social media campaign to help find a match.
Charity Anthony Nolan said 5,600 have signed up in the last week.
"The impact of Vithiya's appeal has been nothing short of incredible," said Ann O'Leary, head of register development, at the charity.
"But Vithiya still needs to find her stem cell match and there are people just like her all across the world who are still waiting.
"We need to continue to diversify the register so we can find a match for all."
Miss Alphons was diagnosed with the aggressive form of blood cancer after falling ill just days after returning for her final year as an optometry student at Cardiff University.
She started feeling unwell with severe sickness and a fever, while she had a pain in her leg, so she went to her doctor for tests.
She underwent chemotherapy in Cardiff before being well enough to be transferred to a hospital in London, where she is from.
After her third course of chemotherapy, Miss Alphons felt better and thought she had beaten her illness.
But further tests showed the leukaemia was still in her blood and doctors told her the best option was a stem cell transplant from a donor, which is needed in the next two months.
Speaking to BBC's Asian Network Miss Alphons said she is grateful for all the support.
"I would just like to say thank you so much to everyone who has registered so far and please, please do carry on registering because you can save my life and you can also save so many other's lives.
"Please spread the word and help me to save my life."