What Precision Medicine Makes Possible

Molly Laufer was doing something she had done hundreds of times before — washing her 3-year-old daughter Charlie’s hair — when she noticed it: a small bulge at the base of Charlie’s neck.

"It looked like she had swallowed a golf ball," Molly recalled.

The next morning, at the pediatrician’s office, the bloodwork came back normal. Charlie seemed fine — no pain, no fatigue, no signs that anything was wrong. The doctor advised Molly to check back in a month if the swelling didn’t subside.

But the following month, the swelling remained, so Charlie went for imaging, which revealed something no parent is prepared for: thyroid cancer that had already spread to the lymph nodes and the lungs.

"It felt like everything just dropped out from under me," Molly said. "There's a before and an after with that kind of diagnosis."

Charlie was referred to specialists at UCSF Benioff Children's Hospitals, and what followed would reshape not only her treatment but also her entire journey.

Looking Beneath the Surface

At UCSF, Charlie’s care team set out to understand what the tumor looked like and what caused it.

Using the UCSF500 cancer gene panel — a comprehensive genomic test offered as part of routine care — clinicians analyzed Charlie’s tumor across hundreds of cancer-associated genes, searching for the genetic changes underlying the disease.

Developed by UCSF’s leading cancer specialists, the UCSF500 test offers exceptional depth and precision in genetic analysis, allowing clinicians to identify specific changes driving a child’s cancer and use that information to guide care. This level of insight can shape treatment from the moment of diagnosis and reveal new options when standard therapies are ineffective.

Charlie’s test revealed a genetic alteration, and that discovery became a turning point.

"This genetic change explained why the tumors were growing," said Natalie Wu, MD, MS, Charlie’s oncologist at UCSF. "And importantly, it pointed us to a therapy designed to target it."

With that insight, Charlie’s care team could move beyond a one-size-fits-all approach and match her treatment to the biology of her disease.

"What’s different about this approach is that we’re not making decisions based on a single piece of information," Dr. Wu said. "We’re integrating what we see clinically with what we learn from genomic testing and using that to guide care in a more precise way."

The Right Plan for Charlie

Charlie underwent surgery to remove the tumor in her thyroid and affected lymph nodes. Then, based on the genetic findings, she began a targeted therapy designed to block the specific change driving her cancer. Within a few months, the residual tumors in her lungs had disappeared. Only after that did she receive radioactive iodine, a more traditional therapy — with the hope that it would be more effective because of the treatment that came before.

Throughout the process, Molly and her husband focused on what they could control. They built routines, created moments of normalcy, and found ways to help Charlie and her siblings make sense of what was happening. Charlie,

who remained unmistakably herself, met each step with openness and light. Along the way, the family came to see how much this personalized approach to treatment was shaping both Charlie’s experience and her outcome.

"With UCSF500, we’re able to look more closely at what’s unique about a child's cancer and use that information to guide each step of care," said Amanda Marinoff, MD, a precision medicine specialist at UCSF. "That allows us to make more informed decisions — not just for one patient but also in ways that continue to move the field forward for all children."

"Bringing that kind of approach to every patient takes more than technology," she continued. “It requires the teams and systems to interpret the data and act on it — and that’s where continued investment makes a real difference."

A Clear Path Forward

Today, Charlie is 5. She plays soccer, dances ballet, and swims. She's also preparing for her next big chapter — kindergarten.

In many ways, her life looks like any other child's: full of movement, routine, and the small, joyful rhythms of childhood. There are still follow-up visits and scans, but where uncertainty once defined the path ahead, there is now clarity — and space to simply be a child.

For Molly, that clarity didn’t happen by chance.

Looking back, she sees how much depended on having access to a system that could go beyond a diagnosis, look deeper, and act on what it found.

“Getting that level of detail — understanding what was actually driving her cancer — that changed everything for her," Molly said. "A diagnosis like this doesn’t discriminate, but the outcome can."

At UCSF, that approach is part of how care is delivered — woven into the way each case is studied, discussed, and treated. “We’re learning more from every patient," Dr. Marinoff said, "and we're using that information to make more informed decisions for the next child."

For Charlie, it meant a treatment plan built around her cancer, and the chance for a full recovery.