You may not have heard of Henrietta Lacks — an African-American woman from Baltimore who died of cervical cancer in 1951 — but you have benefited from her.
A few months before she died, doctors took tissue from Lacks' tumor and grew cells from it. The cells grew and grew. They wouldn't stop growing.
Until then, there hadn't been a "line" of human cells that scientists could test drugs on. Lacks' cells were perfect. There was huge demand for them, and samples were mailed to labs all around the world for testing. The so-called HeLa cells became one of the most important contributions to medical science ever seen.