
By Chris Porter, MD
Pediatric Hematologist/Oncologist
Aflac Cancer & Blood Disorders Center of Children’s Healthcare of Atlanta
Researchers have learned a great deal about how the human immune system can function as physiologic superheroes – able to prevent and cure diseases, including cancer. Like particularly cunning comic book villains, some cancers devise intricate plans to weaken their superhero foes – think kryptonite to Superman. In our lab, we have been investigating how blood cancer cells evade the immune system and have discovered that the cancer cells use a molecular kryptonite, called Siglec15, to weaken the immune cells. Fortunately, there may be ways to shield our immune cells and new ways to strengthen them, which we are actively pursuing every day.
Cancers derived from blood cells, including leukemia and lymphoma, are the most common cancers in children. Thanks to research, cure rates are better than ever. But cancer remains the leading cause of illness-related death in children. Thus, there is a need for better therapies, and understanding how cancer cells behave is critical to developing better medicines.

Dr. Chris Porter
A couple of years ago, our lab found that leukemia cells depend on a protein called calcineurin to evade immune cells. In the cell, calcineurin helps control the expression of a number of other proteins. One of the proteins that calcineurin controls is a signaling molecule, IL-12. This molecule is a member of a family of signaling proteins called cytokines. Researchers have known for a long time that IL-12 very strongly stimulates immune cells to kill cancer cells. However, IL-12 has not been an effective therapy, in part because it can cause several side effects. To get around this problem, we are collaborating with scientists at Emory University and the Georgia Institute of Technology. Together we hope to develop a nanomedicine to deliver IL-12 exactly to where it needs to be, where immune cells interact with cancer cells. This will effectively give additional super-powers to help the immune cells eliminate the cancer cells.
In addition, we found that calcineurin controls the expression of Siglec15, a protein of which not much is known. Leukemia and lymphoma cells seem to make a lot of Siglec15, which we know can inhibit immune cells. In fact, children with leukemia have much higher levels of Siglec15 in their blood than healthy individuals. Now we are trying to understand how the leukemia and lymphoma cells make it and how it inhibits the immune cells. In addition, we are working with a drug company that makes a medicine that can block Siglec15, which could act as a forcefield for the immune cells.
Thus, with funding from CURE, we are making great strides in figuring out ways to strengthen and protect immune cells, which should let these superheroes destroy the villainous cancer cells.


Marc and his wife, Andrea, would soon learn that DIPG is a rare brain cancer for which there is no known cure. As if that wasn’t bad enough, Raegan had the worst possible genetic mutation and was given a prognosis of 6-9 months. Both Marc and Andrea work in the medical field and began scouring the internet for information and potential clinical trials.

Just after her third birthday, Madeline had terrible leg pain and refused to walk, so Bethany took her back to the hospital. Madeline’s blood work showed that inflammation markers were very high, so doctors ordered a total body scan. They found a football-sized mass in her abdomen that had smashed her bladder and pushed into her intestines, kidney, and liver. A biopsy of the mass confirmed a diagnosis of neuroblastoma.
Another part of the APMP is the genetic predisposition program, which provides care for children who are at risk for developing cancer due to a cancer predisposition syndrome or a family history of cancer. Madeline’s younger sister, Sedona, has a known genetic disorder called hemihypertrophy. So she was referred to the genetic predisposition clinic to see if her genetic mutation was the same as Madeline’s. If a genetic link between the two was revealed, it might indicate that Sedona had a high risk of developing cancer in the future.






The PT actually helped for a time, but the pain came back. In February 2017, an MRI revealed new lesions. Once again, neuroblastoma had invaded Lauren’s body. The cancer had spread to her bones, bone marrow, lung and pelvis. In all, the imaging indicated 28 spots that were likely active tumors.
When treatment options have been exhausted, there is little hope of survival. But through CURE’s funding of the Aflac Precision Medicine Program, doctors have a new tool in their toolkit. Lauren was enrolled in the program to see if there was a genetic reason her cancer was resisting treatment. Genetic testing revealed Lauren’s tumor had a genetic mutation for which there is a drug known to be effective. Lauren was immediately enrolled in a clinical trial for lorlatinib. She was given a single pill once a day, and after only four cycles, all bone metastases and bone marrow involvement had disappeared. Incredibly, the only tumor remaining at that time showed inactive.



