"When the cancer comes back, you have to either get a bone marrow transplant or cord blood cell," says 12-year-old Josh Maligro.
Maligro is in remission and waiting for a blood cell transplant after battling a rare form of leukemia, known as AML, twice in the last year and a half.
He's been through two rounds of chemotherapy and will be getting a transplant from an umbilical cord blood from a donor who is not related to him. It's been difficult to find any donor.
"Mixed ethnicities have less chance for a match," says pediatric oncologist Dr. Jacob Garcia.
Nobody in Josh's family was a match. They are part Pilipino and Caucasian. So, Children's Hospital of Oakland is having cord blood flown in from Spain.
"Not a perfect match, but is as good a match as we could find that has an acceptable risk going into transplant with the best chance of cure," says Dr. Garcia.
The cord blood has four out of 6 DNA markers that could help josh, because cord blood has a unique biological quality.
"There's something about the immaturity of those cord blood cells that makes them able to adapt more readily to a new individual than someone who's been living and then donates their cells to a transplant recipient," says Dr. Garcia.
Josh's parents know about the risks of an imperfect match, so they are still asking for people with similar ethnic backgrounds to become bone marrow donors or cord blood donors.
"After transplant, because of full body irradiation, the risk of secondary cancers is almost 100 per cent. You kind of want back up, says Josh's mother Desiree Maligro.
Josh wasn't having a good day when we met him, but he put on a brave face anyway. One of the medications to boost his white cell production is causing him a lot of pain.
"Feels like burnin and it won't go away," says Josh.
"It literally puts pressure on his bone marrow and the way he describes it, is like his bones are exploding from the inside," Josh's mother Desiree Maligro.
"As soon as he's better, and his counts are up, they go on to the next step," says Josh's father Brent Maligro.
Josh should be getting his transplant in the next three weeks, if he stays healthy, and, in remission.
"We have to have hope and just be positive that this is going to be what cures him and gets him back living like a 12-year- old," says Desiree.
Josh told us that when he gets well, he wants to go on another Disney Cruise!
You can learn more about donating bone marrow or cord blood click on the links below.