Sharon Berger, 65, of London was diagnosed with Acute Myeloid Leukemia in 2012, and was told that the only available cure was a stem cell transplant from an unrelated donor.

A global search was launched-dubbed the #Spit4Mum campaign-and a matching donor was found within weeks which meant Berger had an apparently successful transplant in May 2013. But a routine blood test recently revealed that, despite a successful transplant, the aggressive nature of her illness means the cancer has returned, and she requires a second transplant.

Blood cancer charity Anthony Nolan is now searching the world’s combined stem cell registries for someone whose tissue type matches that of Berger’s. But the search could prove difficult because of Sharon’s combination of rare tissue types. Because of Sharon’s Jewish heritage, her best match is likely to be an Ashkenazi Jew. But her family encourages everyone who is eligible to join the Anthony Nolan Bone Marrow register, as a potential match.

To join up you must be aged 16-30, in good health, and weigh at least approximately 110 lbs. In particular, Berger’s family is searching for people from Jewish and other ethnic minority backgrounds to join, as they are currently underrepresented on the donor register.

Find out more at www.anthonynolan.org .

To register as a stem cell donor in the U.S. or Israel, visit www.giftoflife.org .

To register to donate stem cells, visit www.bmdw.org .