This is Henrietta Lacks, a woman who has helped biomedical research for over 50 years, despite her never even knowing it.
She was born in 1920, and was originally named Loretta Pleasant. When her mother died in 1924 and her father couldn’t manage looking after his large family, “Hennie” was sent to live with her grandfather Tommie Lacks, who still lived in a former slave cabin on the plantation that was run by her great-grandfather and great uncle.
She had her first child when she was 14 with her first cousin David Lacks, and they married in 1941 after the birth of their second child. They eventually moved to a prominent African-American community in Baltimore, and worked in a steel mill as part of the war effort.
10 years later in January 1950, Henrietta told her cousins that she felt like she had a knot inside of her, she turned out to be pregnant and gave birth to her fifth child, but then experienced heavy bleeding. She was tested for syphilis, but when the results came back as negative, she was referred to John Hopkins Hospital.
A lump was found on her cervix and a biopsy was sent off for testing. Henrietta had malignant epidermoid carcinoma (also known as squamous cell carcinoma) of the cervix.
She underwent radiatiotherapy, which at the time involved sewing radium tube inserts near to the tumour and leaving the ionised radiation to kill the malignant cells. She also underwent X-ray treatments to the area. The doctors were then sure that the cervical cancer was gone, Henrietta also didn’t realise (or wasn’t told), that the treatments had left her infertile.
But in early August, 1951, she admitted herself into hospital due to the pain she was in, and she died two months later at the age of 31 from renal failure. An autopsy showed that the cancer had spread to numerous regions of her body.
What happened after her death has helped shape and ultimately change modern medicine.
Unknown to Henrietta and her family, two samples (healthy and cancerous) of tissue were taken from her cervix whilst she was undergoing her treatment. These samples were given to Dr. George Otto Gey, who then set about trying to culture and grow more cells.
Culturing cells is not an easy task, there are many factors to consider such as temperature, pH, dead cells building up, depleting nutrients and contact inhibition, which is when cells stop growing when they come into contact with each other (which naturally occurs in the human body, an easy way to explain this is when skin regrows after a cut, it stops when the wound has healed). There is also the major problem of the Hayflick limit, which is the number of times a cell will replicate itself before it completely stops, which is now understood to be due to reduced telomere length.
And yet, somehow, Henrietta’s cells, labelled as HeLa, continued to grow. To this day, HeLa cells are continuously growing in laboratories around the world, creating a new generation every 24 hours, which is incredibly fast.
It’s believed that more HeLa cells have been grown and cultured around the world than were originally in Henrietta Lacks’ body.
Why are these cells still growing?
HeLa cells are now classed as an “immortal cell line” – they just don’t stop growing. Henrietta’s cancer was caused by the human papilloma virus 18 (HPV18), which along with HPV16 is a well known cause of cervical cancer, for which a vaccine has now been made to combat it (I myself received it in school). It has been found that a genetic transfer took place between HPV18 and the malignant cells, turning on an oncogene (tumour causing gene) and therefore creating a highly aggressive cancer line. Also, the transfer of HPV genes has also led to HeLA cells carrying extra chromosomes. Normal human cells contain 23 pairs (46 in total), Henrietta’s other cells were normal, but the cancerous cells, and the subsequent HeLa cell lines can contain as many as 80 chromosomes.
As mentioned earlier, the Hayflick limit is due to telomere length. Telomeres are non-coding repetitive sequences of DNA that sit on the ends of chromosomes. They stop chromosomes from fusing together and protect the ‘real’ DNA of each chromosome. When a cell replicates, a small portion of the telomere is lost; when they become too short and the safety of the chromosome is threatened, the cell will no longer replicate.
Telomeres are thought to be the key to the ageing process, but what is interesting about cancer cells, including the HeLa line, is that they seem to be able to regrow their telomeres using an enzyme called telomerase. This process isn’t fully understood however.
What have we learnt from HeLa?
- The polio vaccine was developed in the early 1950’s thanks to HeLa. It was found that the cells could be easily infected by poliomyelitis, and the vaccine was developed in the space of a couple of years. Polio is now extremely rare in the Western world.
- In the mid 1960s, HeLa cells were fused with mouse cells, creating the first hybrid. This began the process of mapping the human genome.
- Cancer research as we know it is due to research on HeLa cells.
- There have been tens of thousands of experiments carried out on HeLa cells, from leukaemia research to the human digestion of lactose.
Was it ethical to take her cells?
Though Henrietta and her family were not informed at the time of the cells being taken, it was standard procedure at the time. The family didn’t actually find out until the early 1970’s. This year, HeLa cells had their genome mapped, with the results being made public, which created issues over privacy. Luckily, members of the Lacks family, Henrietta’s descendants, have joined the HeLa Genome Data Access group, which looks at applications for the use of that genome.
The Immortal Life of Henrietta Lacks – by Rebecca Skloot. If you’re interested in this subject, I’d recommend this book to you.