The family of a teenager with leukaemia have urged people to sign up to the stem cell register, as a transplant is his only chance of survival.
The call for help from 16 to 30-year-old males is being made by the family of 14-year-old Daniel Greer, of Newry, County Down, who was diagnosed with acute myeloid leukaemia two months ago.
Doctors have said his only chance of survival is with a stem cell donation which would help rebuild his immune system.
Daniel has been staying at the Royal Belfast Hospital for Sick Children since his diagnosis and is being treated with aggressive chemotherapy.
Young men make up more than half of all stem cell transplants for blood cancer and blood disorder patients, but they make up just 18% of the register, according to the Anthony Nolan blood cancer charity, which is helping with the international appeal - dubbed the DoItForDaniel campaign.
His mother, Anne Greer, said: "Daniel is an amazing, bright young man who lights up any room he walks into.
"His wicked sense of humour keeps our spirits up, even now while he's in hospital receiving chemotherapy.
"I know he's really proud that his story is inspiring people to sign up to the stem cell register.
"Those people will potentially help him, as well as many other people around the world who desperately need a stem cell transplant like Daniel."
Daniel complained of back and neck pain before a series of blood tests confirmed his illness.
Aggressive chemotherapy is being used to place him into remission, so he may be able to receive a transplant.
Only one in four people will find a match within their family. However, Daniel's older brother, James, is not a match and so he needs a stem cell transplant from an unrelated donor.
Home town support has so far included encouragement from pharmacies in Newry for people to sign up to the register.
There has also been an awareness-raising drive about stem cell donation at Belfast International Airport.
Anthony Nolan chief executive Henny Braund said: "Finding his matching donor would mean everything to Daniel and his family. We are committed to supporting Daniel as he waits for news of the donor who could save his life.
"Last year over 1,300 people around the world with blood cancer or a blood disorder were given a second chance of life because of the wonderful people that are signed up to the Anthony Nolan register.
"But too many people, like Daniel, are told there is no matching donor for them.
"Signing up to the register is quick and simple, and we urge anyone who is in good general health, especially young men aged 16-30, to come forward and potentially save the life of someone like Daniel."
People aged 16-30 can go online to join the Anthony Nolan register.