A Massachusetts teen is fighting cancer with a big support system behind her.

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Since Natalia Donnelly's brain cancer diagnosis, the community has rallied behind the Norwood 15-year-old and her single mother.

A T-shirt was sold as part of a fundraiser for Natalia with the words on the back, "Fight like a girl" and "Team Natalia," and boy, does she have a team behind her. 

It was the day before Natalia's first day of high school when she got the devastating diagnosis. Then 14, she learned she had a cancerous brain tumor.

"Hearing that was just like, obviously, a parent’s worst nightmare," said Jeanie Donnelly, Natalia's mother. "You just have a mother’s instinct. You just know."

After having surgery, Natalia would need six months of chemo and six weeks of radiation.

"She’s strong. I get my strength from her," her mother said.

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Since September, Natalia's been bravely undergoing treatments, with no complaints. Her mother has been beside her, often, for five-day hospital stays.

"You have two options. Either you, you pick up and you keep going or you fall apart.," her mother said. "I have to stay strong for her and myself, to get through it."

For Natalia, battling a ruthless disease, losing her hair and feeling sick have been tough enough. But the worst part?

"Not being able to go to school," Natalia said.

She is taking online classes through Norwood High, but it's hard missing friends and teenage experiences.

"I was going to do volleyball and lacrosse this year, but I can’t really do those," Natalia said.

But what's uplifted them during difficult times is the community's support. Meals delivered and fundraisers organized. Donations that Jeanie, the sole provider, relies on to be at Natalia's bedside every moment.

"When I’m at the hospital five days a week, I’m not working, so I don’t have an income," her mother said. "So it’s been a tremendous help knowing that I can be at the hospital and my bills aren’t falling behind."

Natalia turned 15 on Sunday. On Tuesday, her latest MRI showed no tumors.

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It's a tremendous relief for Natalia and her mom. While they know she's at risk of developing cancer later in life, with their support system behind them, they are determined to beat the disease.

"I can’t even say how thankful I am because of it," her mother said.

Next week, Natalia starts another round of chemo. Those fundraisers continue.

One of the most successful campaigns has been a GoFundMe account set up in Natalia's name.