But Henrietta's family did not know any of this until the 1970s when medical researchers contacted them asking for their blood samples. Only in the past 18 months have family members been invited by one organisation to join a committee regulating access to the cells.
Her story raises salient contemporary questions about who might own our bodily remains and the commercial uses of these, but it's also a biographical and family drama about an unknown woman.
Speaking from her base in Glasgow, Onashile says she first heard of Henrietta Lacks in 2011 when a friend told her about science journalist Rebecca Skloot's book The Immortal Life of Henrietta Lacks.
Onashile stopped at a bookstore on her way home, bought a copy, started reading and didn't stop until she finished it 12 hours later.
She had never written a play before, but knew this was the story she wanted to bring to the stage. Like Skloot, Onashile saw the story's more humane side inherent in the contrast between wealthy, politically powerful research companies and the disenfranchised Lacks family, who couldn't afford a headstone for Henrietta's grave.
"I like work that contains uncomfortable truths and where situations are not black and white but full of shades of grey and I think the issues Henrietta's story gives rise to certainly fall into this category, but it's also an amazing story.
"When you think about where Henrietta's cells have ended up and the contributions they have made, it's just mind-blowing. I was fascinated by the idea of someone being so present when they are dead and the questions it raises about the nature of life but also, as Henrietta's daughter Deborah believes, her mother's spirit being alive in those cells."
She contacted Skloot and received her blessing to adapt the book for the stage but, despite repeated attempts, was unable to contact the Lacks family.
"I felt less unnerved about going ahead when I learned they want to spread the word about Henrietta and HeLa cells. I hope the show is doing what they want by getting the word out there."
It completes in New Zealand a world tour, meaning Onashile has had plenty of time to craft the production. The main challenges she faced were dealing with her own anger at the inherent racism in the story - "it's a Jim Crow tale where Henrietta's name was purposefully hidden" - and how to make the science accessible to audiences.
She worked with dramaturge/director Graham Eatough who helped her channel her feelings into the story and find a balance between the science and the human drama. From the outset, Onashile and Eatough decided Henrietta would be silent.
"I thought it was important to keep her silent, partly as a metaphor for the fact we don't know what she would make of all this - and no one asked her for her consent - but also so people could come away feeling they wanted to know more about her, which is part of the fascination of the story."
Onashile says video and music helps break down the science, adding at times an almost documentary feel to the production.
"The issues it highlights are pertinent at the moment and I don't just mean the ethical side of the story, but how we view science, especially when scientists are trying to make it more accessible to the layperson. There are ways of looking at this, as Henrietta's daughter does, which involve questions about memory and more spiritual aspects. It allows for various perspectives to be considered against the background of an amazing story.
"This is the first play I wrote and I am honoured that I can present this work. From an artistic point of view, I have learned and grown so much but it's a story that's bigger than me and I love being in the service of a story which honours this woman."
What: HeLa
Where and when: Loft, Q Theatre, October 21-25
