A Reddit user wants to give back to a former teacher by helping out his daughter.

Lara Casalotti, 24, suffers from rapidly progressing acute myeloid leukemia, and she needs a stem cell transplant to save her life.

Unfortunately, finding a genetic match for her has been difficult. Casalotti is Chinese-Thai and Italian, and less than 3 percent of registered donors are mixed race. Of that small percentage, “only a fraction of [the registered donors] are an Asian-European mix most likely to match with Lara,” according to match4lara, a website created by Casalotti’s family to help find a donor.

“All of us in the family wanted so badly to be the match. I must have hit the refresh button a hundred times on the online test results page, before finally getting my markers. They didn’t match. None of ours do.”

That’s why redditor Yasmeenaccounts posted about the family’s situation in the Videos community, trying to spread the word and find an acceptable donor.

“Please, can you guys help?” Yasmeenaccounts wrote in the post. “He was honestly such a nice teacher and I really want to help his family.”

People interested in helping Casalotti and finding if they’re a genetic match can join a bone marrow registry. The match4lara website has links to registries in the US, Great Britain, and other countries, and matches are found by taking a cheek swab or saliva sample from volunteers. Even if an individual isn’t a match for Casalotti, they might be a match for one of the 12,000 other people in need of a donation.