Grandmother Who Ran NYC Marathon Using Social Media Fame For A Good Cause

CEDARHURST, N.Y. (CBSNewYork) -- A grandmother on Long Island has turned into a social media sensation.

She crossed the finish line of the New York City Marathon after dark on Sunday, but now she's shining light on a very important cause, CBS2's Jennifer McLogan reported.

"I knew that I was crossing the finish line. There was not a doubt about that," said Sondra Rose. (McLogan: How many hours?) More than 9 hours."

Rose celebrates her 78th birthday in two weeks and has become a surprise inspiration to complete strangers.

Since her marathon finish was posted on social media, it has garnered more than 700,000 views.

"Of course, when I see my beloved waiting for me -- ahh, I just couldn't wait to fall into his arms," Rose said. "That makes it all so special."

She's talking about husband Marvin.

In 2008, the couple's grandson was diagnosed with non-Hodgins Lymphoma, and life changed immediately for the Cedarhurst family.

"All I want to do is raise money for my cause. That's been my passion since Jack was diagnosed," Rose said.

Web Extra: Sondra Rose Fundraising Page | Spa Mavin Trips For Charities

Rose began running, hiking, camping, and sponsoring spa trips to help raise money for the Leukemia and Lymphoma Society.

"He went into remission as soon as he started receiving the treatment, and so I tell myself someone either donated or raised the funds that developed the research that helped Jack. And that is why I do what I do," Rose said.

With her support team, Rose helps fund research with the hope of finding a cure.

"Every day when I open the mail and I look to see if I got a check, that means it's a good day," Rose said.

So far, Rose has raised and donated $350,000 from her athletic activities' fundraising, McLogan reported.

"So despite gray hair and some wrinkles, anything is possible," Rose said.

Rose's unexpected fame is also helping -- by example -- women who may think they are too old to lead active lives.