a promise.

How's this for a legacy? (quotes from wikipedia)

"Nancy G. Brinker promised her dying older sister, Susan G. Komen, she would do everything in her power to end breast cancer forever.

 

In 1982, that promise became Susan G. Komen for the Cure, which is now the world's largest breast cancer organization and largest source of nonprofit fund dedicated to breast cancer.

 

Since its inception in 1982, Komen has raised over $1.5 billion for research, education and health services, making it the largest breast cancer charity in the world. Today, the Komen organization is recognized as the leading catalyst in the fight against breast cancer, with more than 100,000 volunteers working in a network of 125 U.S. and international affiliates.”