Cancer-Stricken Infant Who Was Kissed by Pope Is Responding to Treatment, Parents Say

— -- An infant battling brain cancer, who famously was kissed by Pope Francis during the pontiff's historic visit to the U.S. this year, is responding to treatment, according to her parents.

Gianna Masciantonio, 1, was diagnosed with a rare form of brain tumor called systemic juvenile xanthogranuloma (JXG) months after being born, her parents said. Doctors spotted the inoperable tumor on her brain stem and told her parents she would likely not survive for more than a few weeks.

"Her life was a miracle," Gianna's father, Joe Masicantonio, told ABC News. "They told us to go home and spend days to weeks," with her.

Gianna had been in hospice care since shortly after she was born, and when the infant developed cysts, an 11-hour operation to drain the cysts led to the rare diagnosis of JXG. Though the tumor itself is benign, the location on the brain stem is potentially deadly because it can affect Gianna's ability to breathe and for her heart to beat, according to her mother Kristen Masciantonio.

Since the surgery, Gianna has been on multiple chemotherapy treatments to try and shrink the tumor, said her parents, who are devout Catholic.

Earlier this year, the Masciantonio family celebrated when Gianna was kissed by Pope Francis during a parade in Philadelphia. Joe Masciantonio said the visit helped cement how important their faith was to them throughout this ordeal.

While Joe Masciantonio said Gianna's tumor shrunk after her papal visit, he said he did not want to call it "a miracle" and that he also wanted to draw attention to her doctors at the Children's Hospital of Philadelphia and Texas Children's Hospital.

Kristen Masciantonio said the last courses of treatment occurred just before she got to meet Pope Francis. She said they were nervous about bringing her to the crowd but decided at the last minute to risk it.

"Pope Francis kissing her was my miracle, was the way of God telling me he was with us," Kristen Masciantonio said.

Joe Masciantonio said Gianna will continue to undergo chemotherapy and the tumor remains inoperable due to its placement on her brain stem. He said for now the family is enjoying all the time they have with her.

"She’s the toughest baby I’ve ever seen in my life," he told ABC News. "She’s our inspiration. She’s really the best little girl."