Quick guide to HeLa cells
What are HeLa cells?
HeLa cells are human cervical cancer cells (the cervix is found at the top of the vagina). The cells were first cultured, or grown, in a laboratory in 1951 and were the first type of human cancer cell to be cultured continuously for experiments. There are lots of different strains (subtypes) of HeLa cells that are now used.
How do HeLa cells grow continuously?
HeLa cells grow rapidly given the right medium (nutrients and conditions) and space. This is because HeLa cells are cancer cells, which multiply and grow quickly in an uncontrolled way, compared to normal cells. They can also spread and infect other cells.
HeLa cells became cancerous due to infection with human papilloma virus 18 (HPV18). Cervical cancer is very closely associated with HPV 16 and HPV18, which can subvert the normal activity of the cell to make cells become cancerous. However, not every woman that contracts one of these viruses will develop cervical cancer.
In normal cells, the Hayflick limit means cells can only create copies of themselves a certain number of times as the telomeres at the ends of the chromosomes shorten with each division. This doesn't apply to many types of cancer cells because they produce an enzyme called telomerase. This enzyme elongates the telomeres after chromosomes are copied, so the cells can multiply continuously.
HeLa cells come from a sample taken from a woman called Henrietta Lacks and were named using the two initials of her first (He) and last (La) names. She had a cervical tumour, from which she died some months later, so she never knew that her cells became a cell line that would be widely used in science.
How have HeLa cells been used in science?
The doctor who took Henrietta's cells - George Gey - grew them in the lab and distributed them to other scientists across the world to use in their experiments. They have made a significant impact in science research. Scientists have used HeLa cells to develop the polio vaccine, they have gone into space and have been exposed to nuclear testing and to toxins. The cells have furthered our understanding of cancer, HIV/AIDS and cells in general, and are still widely used today to grow viruses and to test anti-tumour medicines.
Ethical and moral questions about HeLa cells
The moral and ethical issues surrounding HeLa cells and other human cell lines are still much debated.
Should patients' identities be protected?
The process of naming cell lines has changed since the 1950s to prevent people finding out who cells come from. It became widely known that HeLa cells came from Henrietta Lacks, despite other names such as Helen Lane being used to try to maintain her anonymity. The family of Henrietta Lacks did not know Henrietta's cells were being using by scientists and they were exposed to unwanted intrusion and attention. Today, cell lines are anonymised so they can’t be traced to a named person. For more, see the Department of Health - information on patient confidentiality.
Should patients give consent?
The Lacks family never understood how the cells would be used and it wasn't explained to them. This led to a lot of anxiety and strain on the family. The issue of consent is still widely debated. For more on this see the Nuffield Council on Bioethics - information on using human tissue.
Should companies be able to profit from cultured cells?
The Lacks family were unable to afford healthcare in the USA. Henrietta Lacks did receive free healthcare treatment for her cervical cancer, but, as she was African American, she had to travel miles to a segregated hospital to be treated. George Gey, the doctor who treated Henrietta Lacks, didn't profit from the cells when he sent them to other scientists. Yet, some pharmaceutical businesses cultured HeLa cells and have profited by their manufacture.
- Do you think people should let their cells or tissues be used in scientific research?
- Do you think it's a good idea if people have to give consent before their tissues can be used?
- Do you think it was right to take the cells from Henrietta Lacks?
Read our Q and A with Rebecca Skloot ,">Q and A with Rebecca Skloot , who has written a book about Henrietta Lacks and the story of HeLa cells, which won the Wellcome Trust Book Prize 2010.
Image: HeLa cells showing nuclei and nucleoli. Credit: Laura Trinkle-Mulcahy, Wellcome Images.
This article is part of the exclusive online content for ‘Big Picture: The Cell’. Find out more about the ‘Big Picture’ series.