Friends recall Henrietta as a kind and uncommonly pretty woman who liked fine dresses. She had her children in quick succession, the youngest born only weeks before she fell ill in 1951. It was then that she was diagnosed with cervical cancer. The cancer killed her within eight months.
Only in death did Henrietta Lacks become extraordinary. Unwittingly, she achieved a sort of immortality: cells from her body exist today in laboratories all over the world; in fact, the number of her cells still living amounts to 400 times her original weight. They have transformed medicine and have been used for hundreds of different projects - the development of the polio vaccine, the effect of zero gravity on the body and the search for a cure for cancer.
Henrietta's life would have been no different from that of thousands of other women had it not been for two factors: the cell biologist Dr George Gey and the cancer she fell victim to. Dr Gey, who worked at John Hopkins University, Baltimore, was determined to be the one to find the cure for cancer. He arranged that any patient brought into the hospital with cancer should have cells removed, and when Henrietta was diagnosed a biopsy was performed.
From the beginning it was clear that her cells were different. Dr Howard Jones, the gynaecologist who treated her, says: "On examination of her cervix by the eye ... I was extremely impressed. I can see that lesion today because it was not like an ordinary cancer. This was different ... I'd never seen anything look like it." Using Henrietta's cells, Dr Gey managed for the first time to grow human cells successfully and continuously outside the body by mixing them with chicken plasma. No one knows what made her cancer so strong but within six weeks the cells were dividing every 20 hours. For any cancer it was a record growth rate.
On the night of her death - 4 October, 1951 - Dr Gey appeared on a television science programme showing off his findings. Meanwhile his assistant Mary Kubicek was in the autopsy room collecting more cells from the body: "You could look in and see tumour everywhere on all her tissues," Ms Kubicek says.
"She was very, very thin and yet one thing I did notice was she had chipped red nail polish on her toenails and I thought, `This was a live woman not just a body.' "
Henrietta was taken back down south to be buried in an unmarked grave alongside the plantation her great-grandfather had owned. She was forgotten, but her constantly growing cell line - now code-named HeLa - became more and more important.
The success of HeLa heralded a new form of medical technology which enabled scientists to study human cells in vitro. The cells were sent up into space with two white mice as part of the 1960 project Discover 17 to see if the human body disintegrated in zero gravity. HeLa proved it did not. Cosmetic companies queued up to buy her to test for allergies. Even sticky tape manufacturers bought cell lines so that they could test that the combination of chemicals were safe for humans.
The first major contribution she made was to the development of the polio vaccine in 1954. Before HeLa the polio virus had had to be grown on monkey cells. Now they had the opportunity to examine what happened to the structure of human cells when the virus was added to it.
With the success of polio studies, scientists came up with the idea that cancer too might be caused by a virus. The idea of a viral cause - which would mean a vaccine could potentially be developed - was seductive, particularly when a millionaire society hostess Mary Lasker took up the cause. Her husband had died of cancer and she was desperate for the US government to inject money into research. The idea that cancer could be prevented by a vaccine was a simple one that she could sell to politicians.
She enlisted the help of stars such as Bing Crosby and Joan Crawford to raise the campaign's profile. And finally it seemed scientists were on the verge of a major breakthrough as they collected cell lines from different people.
But they had reckoned without Henrietta. By 1967 it was clear that something was seriously wrong. Stanley Gartler, a geneticist who analysed the enzymes cells produced revealed that after analysing many cell lines taken from whites he had found they had all contained a certain enzyme - G6PD Type A- one that could only be found in blacks.
Leonard Hayflick, a white cell biologist had grown a cell line from his daughter's amniotic fluid: "Gartler was saying my daughter's cells had the enzyme characteristics of a black parent which was the reason I ran to the telephone to speak to my wife. She assured me I had nothing to worry about."
Henrietta's cells were so powerful that if just one cell dropped on to another petrie dish or if one was blown across the laboratory they would grow so aggressively that the host was smothered, turning normal cells cancerous. Thinking they were analysing different cell lines, scientists had been studying HeLa all along.
"It was a scandal, to put it mildly. It was something terribly, terribly wrong," says Walter Nelson-Rees a cell biologist who ran the National Cell Bank for the National Institutes of Health. He was brought into investigate contamination after it was found that HeLa cells had even infiltrated Building 41, the most secure lab in the world. "It was devastating ultimately to have wasted three or four years on the wrong cells. It's comparable to thinking you are living in a palace when you're living in a log cabin."
Despite these problems, the war on cancer - the biggest funded medical project in history - was declared in 1971. In 1972 there appeared to be a breakthrough. The Russians triumphantly announced that they had found the cancer virus in five different cell lines. Dejected, an American delegation went to Moscow to see for themselves.
The lines were brought back for examination. But there appeared to be something wrong. When Nelson-Rees analysed them he came to the conclusion they had all been derived from blacks. Although he knew there was a large black contingent in Moscow he thought there was "something fishy". Further chromosomal analysis proved his suspicion right. All the lines were identical to HeLa. Henrietta had got through the Iron Curtain by infecting other lines. The news was a "slap in the face" for the Russians.
The viral hypothesis exhausted, scientists turned to a new idea - a genetic cause for cancer. Once again Henrietta came into her own when an Oxford geneticist Professor Henry Harris fused HeLa cells with that of a mouse. Mixing HeLa genes and mouse genes in different patterns allowed scientists to deduce the position of each gene in the cell. Henrietta had helped develop gene mapping.
Needing to know more about Henrietta's genetic make-up, scientists returned to her family 20 years after her death. But no one had ever thought to inform the Lacks what had happened to their mother. They were shocked and angry: "We never knew this. I was upset," said Deborah Lacks Pullum, her daughter. "It was like `is there anything else I don't know?' And it's scary when you think about it. I mean how many of her cells are out there?"
But for the biotechnology industry gene mapping was a chance to make megabucks and companies seized the opportunity. The Lacks family thought it wasn't right that companies could make so much money out of their mother and tried to lay claim to her cells: "They are selling her cells all over the world," says David, another of Henrietta's children. "I just wanted to find out who is making money off my mother's cells. I was kinda angry about it ... because it was something no one knew about."
Their lawyers approached all the major biotechnology companies to find if they were using her cells. Almost all were but no legal case could be brought because she had died too long ago.
Instead, the family turned to the radical black press who took up Henrietta's cause, arguing that her contribution to medicine should be recognised. Her experience was reinterpreted as a sacrifice by a black woman for the good of humanity.
After extensive campaigning the family finally achieved their aim last October when Moorhouse College in Atlanta, one of the oldest black colleges in America honoured her and her family. The mayor of the city then announced that 11 October would henceforth been known as Henrietta Lacks Day in Atlanta because of her role as a "scientific heroine".
But ultimately Henrietta has defeated the scientists who used her. Despite work on her cells for more than 40 years, she has kept the secret of a cancer cure. "The dream of making a lot of money did happen for a lot of people," says Kirk Raab, the former president of the American biotech company Genentech Inc. "but the dream of curing cancer has not"
Henrietta Lacks's story is told in `Modern Times :The Way of All Flesh' on Wednesday 19 March at 9pm on BBC2