The Immortal Life of Henrietta Lacks April 22, 8 p.m., HBO.

Rebecca Skloot’s best-selling 2010 book The Immortal Life of Henrietta Lacks represents an effort to shine a light on the black woman whose cells, “donated” to science without her knowledge or consent, provided the basis for dozens of breakthroughs in modern medicine thanks to their ability to remain alive in a laboratory setting. Skloot helped bring Lacks’ life story to the public, so it’s a bit ironic that in the movie based on Skloot’s book, Lacks herself is a minor character seen only in flashbacks.

Although Oprah Winfrey gets top billing in director and co-writer George C. Wolfe’s adaptation, Rose Byrne as Skloot is really the main character. Skloot befriends Lacks’ volatile daughter Deborah (Winfrey), who serves as her guide in learning about the life of the woman who gave so much to science. But that woman (played by Renée Elise Goldsberry) gets only a handful of scenes, and the movie turns into the story of a journalist’s struggles to write a book. It’s often hokey and overstated, with Winfrey giving a broad, showy performance. By the end, you get the idea that Henrietta Lacks was very important, but as a person, she remains distant. Maybe there’s a book that could address that.