POULSBO — Katie Gerstenberger and Hannah Hunt each had cancer — Katie, a rare form; Hannah, a common and aggressive one — and they weren’t going to give in without a fight.

They underwent treatment and surgeries. They recovered and relapsed. They had dreams for the future — Katie wanted to be an actor or a writer, Hannah wanted to be a teacher — but those dreams changed. Because of what they endured and what they saw others enduring at Children’s Hospital, both wanted to help cure cancer.

And when their diagnoses were terminal, they still didn’t give up the fight; each laid the foundation for the battle to continue, for the research to be done, so that other lives may be lived.

Katie and Hannah each died at age 12. But the efforts they inspired live on, having raised hundreds of thousands of dollars for research at Seattle Children’s Hospital. And that research is making a difference.

Dr. Michael Jensen has developed an immunotherapy that uses the patient’s own T cells — white blood cells in the immune system that fight infection — to seek out and destroy cancer cells in the body. According to Katie’s mom Karen, this treatment “has saved 11 children who had no more hope.”

And Dr. Jim Olson developed Tumor Paint, derived from scorpion venom, which “lights up” cancerous cells, enabling surgeons to differentiate diseased from healthy tissue. The result is a more precise and complete surgical removal of cancerous tissue, while sparing surrounding normal tissue.

Hannah’s mom, Reba Ferguson, said, “It’s going to be different for the next generation.”

The troops have breached cancer’s fortress walls. You can be a soldier in Katie and Hannah’s army by attending an event presented by Hannah’s Hopeful Hearts, 7 p.m. April 10, at Grace Church on Bainbridge Island. The evening will feature hors d’oeuvres, dessert, beer and wine, and a concert by St. Paul de Vence.

The highlight of the evening: Presentations by Dr. Olson, hematology-oncology physician at Seattle Children’s and director of Project Violet at the Fred Hutchinson Cancer Research Center; and Dr. Jensen, director of the Ben Towne Center for Childhood Cancer Research at Seattle Children’s and a force behind the Strong Against Cancer Initiative.

All proceeds from each $40 ticket — $75 per couple — will help support Olson and Jensen’s work. Tickets are available at www.hannahshopeful

hearts.brownpapertickets.com. The event costs are being underwritten by Windermere Real Estate/Bainbridge Island, where Hannah’s father has been a broker for 36 years.

The Katie Gerstenberger Endowment for Cancer Research at Seattle Children’s Hospital was established at Katie’s direction and helps fund Jensen’s research. Hannah’s Hopeful Hearts helps fund Olson’s research.

Katie died in August 2007 from adrenocortical carcinoma, described as an aggressive cancer originating in the outer layer, or steroid-producing tissue, of the adrenal gland. Hannah died from medulloblastoma, a brain cancer, in August 2010, two days before the start of her seventh-grade year at Woodward Middle School.

Since their passings, Katie’s endowment has grown to more than $295,000, the income from which supports research at the Ben Towne Center at Seattle Children’s, and Hannah’s Hopeful Hearts has contributed an undetermined amount for research, raising more than $100,000 at one event, Ferguson said. For the April 10 event, donors have pledged matching gifts of $65,000.

Katie and Hannah were born three years apart, grew up in different communities and did not know each other, but their stories are similar.

Katie grew up in Poulsbo, the daughter of Gregg and Karen Gerstenberger.

Until her diagnosis, Katie had “an incredibly healthy childhood,” Karen said.

“She was interested in acting. She liked reading stories. She wanted to become a writer. She wanted to have a family. She was very funny and strong willed. She took drama and piano. She loved her friends. She loved the beach. She was very imaginative and very feminine.”

Katie was also strong and incredibly brave. “She went through 10 months of treatment, underwent an 18-hour surgery and had a huge recovery from that, then relapsed,” Karen said.

When her diagnosis became terminal, Katie wrote a will. She bequeathed 50 percent of her money to Goodwill, and 50 percent to her brother and parents. She gifted her books to the public library. Following their daughter’s lead — “I want to cure tumors like mine,” she said — her family asked for donations to Children’s Hospital in lieu of flowers.

“For a 12-year-old girl to face death like that,” Karen said, still astonished by her daughter’s bravery. “Even at the end, she did what she could do to effect change.”

Karen and Katie’s journey together through treatment inspired Karen’s 278-page book, “Because of Katie,” published in 2008. Paula D’Arcy, author of “Gift of the Red Bird” and “When People Grieve,” called the book “a beautiful, forceful story.”

Hannah grew up on Bainbridge Island, the daughter of Bill Hunt and Reba Ferguson.

“She was really upbeat and positive — a funny, friendly girl,” Ferguson said. “Many called her their best friend, because she was a friend to so many. She loved her friends, her family, her pets. She was really into school, which made her ordeal so tough. She was in trials for three years and missed all of fourth grade. Surgery and chemo and radiation each took her down a few notches, gradually robbing her of her cognitive capacities.”

Through it all, Hannah never gave up, taking up yoga and bolstering her immune system with vitamins and supplements. She never complained. And in March 2010, she attended the first Hannah’s Hopeful Hearts event at Grace Church, the event that raised six figures to support Dr. Olson’s research. Hannah had become a force in the effort to cure cancer.

Hannah died five months after the 2010 fundraiser. The April 10 event will be a poignant one for Olson — his first return to Grace Church and Bainbridge Island.

And so, the efforts spurred by Katie and Hannah continue, beckoning others to join the battle.

“She changed from wanting to be a teacher to wanting to be a doctor who cured cancer,” Ferguson said of Hannah. “She would want us to keep fighting.”

ONLINE: See videos about the Olson and Jensen’s research at www.vimeo.com/72117265 and www.vimeo.com/29799436.

For more information about the Katie Gerstenberger Endowment, go to www.katiegerstenbergerendowment.blogspot.com. For more information about Hannah’s Hopeful Hearts, go to www.hannahshopefulhearts.wordpress.com.