Here's a story that shows how, in rare genetic cancers, every case matters.

Megan Flynn, a 34-year-old Edina woman, had a rare ovarian cancer at age 17. She provided her health and genetic history to doctors at Children's Hospitals and Clinics of Minnesota to help build their two registries of childhood cancers tied to the human DICER1 gene.

As a result, she found out her infant son had the same genetic mutation — and a related and equally rare lung cancer. But because it was discovered when he was only three months old, doctors were able to remove the tumor when it was at its most treatable stage, and save his life.

"That is the great hope of this research," said Dr. Kris Ann Schultz, a Children's pediatric oncologist.

Since publicity of Flynn's story emerged in early June, two more families have contacted Children's about adding their genetic and cancer history to its registries.

"In such a rare disease, every single patient is critical," Schultz said, because the collection of information provides clarity on risk levels related to genetic mutations, and on treatments that work best for the different cancers.

A mutation of the DICER1 gene was discovered in 2009 to be associated with pleuropulmonary blastoma (PPB), a rare but aggressive lung cancer that Flynn's son, Andrew, suffered. Children's now has a registry of 450 people with PPB diagnoses. In 2011, the mutation was connected to the rare ovarian and testicular stromal tumors that patients such as Flynn have suffered. A registry of those cancers now includes 65 people, including Flynn.

The registries, which are funded by charities such as the annual Pine Tree Apple tennis tournament, can help determine when to screen children whose relatives carry the mutation, and the likelihood that children with the mutation will develop tumors.

"Child cancer research is not just about doctors working in the clinic," Schultz said, "It's everybody working all together, and that includes patients and families."