Four-year-old Katie Herron needs a stem cell donation to save her life. Her family hopes to find that donor at a clinic being held this Saturday.

Katie is battling acute lymphoblastic leukemia and no one in her family or the national stem cell registry has been a match so far.

Her parents Anne Hodgkinson and Paul Herron, along with an army of volunteers, are hosting a donor clinic at the Cambridge Sports Park, located at 1001 Franklin Blvd., from 1 p.m.-5 p.m. on Saturday.

Click here for the Facebook page with more information.

Men and women between the ages of 17-35 can qualify to donate stem cells. The test is a simple cheek swab, and, if it’s a match, a blood or bone marrow sample will later be extracted.

Anyone over 35 wishing to contribute is encouraged to donate blood, as patients waiting for transplants require frequent blood transfusions, according to the event’s Facebook page.

This is the little girl’s second time dealing with a battery of tests, treatments and hospital stays. She was first diagnosed at fifteen months, but Katie fought the cancer into remission.

Then last November, just after starting junior kindergarten, the cancer returned.

Though the type of cancer young Katie is facing often responds well to standard treatment, Katie is one of the unlucky children for whom that is not the case.

A stem cell transplant essentially replaces the patient’s white blood cells with healthy ones, enabling the body to better fight off the cancer.

If a donor is found Katie will undergo the transplant at Toronto’s Hospital for Sick Children.