See the first photos of Oprah Winfrey in HBO's Henrietta Lacks movie

As Henrietta Lacks lay dying in the “colored” ward of Johns Hopkins Hospital in 1951, doctors sliced off a bit of her cancerous tumor — without asking — and before long her robust cells, flourishing in petri dishes, helped lead to the discovery of the polio vaccine, in vitro fertilization, and gene mapping. Now the tale, unspooled by Rebecca Skloot in her 2010 best-seller, The Immortal Life of Henrietta Lacks, has become an HBO biopic starring Oprah Winfrey as Lacks’ daughter, Deborah.

“The book connects the epic with the intimate, and that’s the movie’s ambition,” says George C. Wolfe, who adapted and directed it. “This woman’s cells helped heal the planet, yet her children were suffering. They didn’t know their mother’s story, even though they were living in the shadows of Johns Hopkins. I found that dichotomy incredibly moving.”

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Wolfe says the book’s science could be daunting (“I kept reducing it further and further down”), but what intrigued him most was how Lacks’ daughter processed it: “I’m interested in how people create their own mythologies so they can continue to live.”