Marissa, who is only two years older than her sister was when she found out she had cancer, is still working to define herself beyond the moniker of her sister's savior.
"I'm pretty much immune to everything, like the whole story -- my friends knowing, my classmates knowing, everyone knowing ... But I don't really like talking about it," she told "Good Morning America." "I want to be me. That's not my whole life and it's a part of me but I want to be defined as myself."
"Even though, yes, I gave her a second chance at life, we're just normal sisters. I never think about it at all," she added.
Anissa does think about it, though, and has taken steps to make sure the priceless gift of life is not easily forgotten.
On "Good Morning America" today she announced that she is founding a research grant called the "Marissa Eve Ayala Research Grant" with the Leukemia and Lymphoma Society.
Anissa is making the first donation, $10,000, towards a goal of $100,000.
"It's going to be in honor of [Marissa]," she said.
"It's really just brought so much joy to our lives. She's such a beautiful girl and she's such a beautiful person."
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