Les
cellules d’Henrietta Lacks
Au mois de
février 1951, l’histoire de la médecine fut bouleversée par une jeune mère de
famille issue de la communauté noire de Baltimore, aux Etats-unis. A cette
époque, le Dr George Otto Gey dirige le service de recherche sur la culture des
tissus humains à l’hôpital John Hopkins de Baltimore. Il poursuit alors un seul
but : vaincre le cancer. Pour ce faire, sa femme et lui venaient de passer plus
de 20 ans à essayer de maintenir en culture des cellules cancéreuses afin de
pouvoir les étudier. En vain. Jusqu’au jour où leur chemin croisa celui
d’Henrietta Lacks…
Ce jour-là,
quelques instants avant que la médecine n’entre dans un nouvel âge, Henrietta
lacks est étendue dans une salle de l’hôpital Hopkins reservée aux noirs. Mère
de famille agée de 31 ans, elle vient pour se faire soigner une tumeur maligne
au col de l’uterus détectée huit jours plus tôt. Le gynécologue qui la traite
au radium prélève un échantillon de sa tumeur et le fait passer au Dr Gey, qui
fait alors une découverte sans précédent : les cellules d’Henrietta Lacks
sont immortelles.
Jusqu’ici, on
avait jamais pu cultiver de celulles humaines à l’exterieur d’un corps. A cause
du faible nombre de divisions, la lignée cellulaire finissait par s’éteindre.
Mais la présence d’une enzyme particulière dans les cellules d’Henrietta
faisait que celles-ci se divisaient indéfiniment, si bien qu’on pouvait non
seulement les étudier, mais également les distribuer dans d’autres
laboratoires. Elles furent baptisées cellules HeLa (pour Henrietta
Lacks).
Si les cellules
cancéreuses d’Henrietta prospéraient sans limites dans les tubes à essai, elles
faisaient de même dans son organisme, et la malheureuse mourut quelques mois
plus tard, le 5 octobre 1951. Ce qu’elle ignorait, c’est que ses cellules
continueraient à vivre. Elle qui n’avait jamais traversé plus longue distance
que celle séparant la Virginie de Baltimore, elle ne put jamais savoir que ses
cellules se multiplieraient dans les laboratoires du monde entier. Comment
cette petite fille d’esclaves aurait-t-elle pu imaginer que des parcelles
d’elle-même seraient envoyées jusque dans l’espace pour étudier les effets de
la gravité sur les cellules humaines? Et qu’elles permettraient de guérir la
polio?
Aujourd’hui
encore, les cellules HeLa constituent la lignée standard dans le cadre
d’innombrables études liées à la cancerologie, la biologie, ou encore l’effet
des radiations. Elles ont permis de remporter des prix Nobel. Elles ont sauvé
des vies. Et elles sont tellement nombreuses à présent que leur biomasse
dépasse celle du corps tout entier d’Henrietta lorsque celle-ci était vivante.
Mais si de
nombreux scientifiques honorent maintenant la mémoire d’Henrietta Lacks pour
son inestimable contribution à l’avancée de la médecine, il faut préciser
qu’elle fut enterrée sans sépulture décente, et qu’elle ne fut même pas mise au
courant du prélèvement pratiqué sur elle à l’hôpital. Sa famille elle-même ne
l’apprit que 20 ans plus tard. Les cellules d’Henrietta Lacks sont immortelles,
puisse son souvenir l’être aussi.
Source
Cells
That Save Lives Are a Mother's Legacy
REBECCA SKLOOT
 Deborah Lacks closed her eyes as a young cancer
researcher opened the door of his floor-to-ceiling freezer. She stood clutching
the ragged dictionary she uses to look up words like ''DNA,'' ''cell'' and
''immortality.'' When the icy breeze hit her face, she opened her eyes slowly,
and stared into a freezer filled with tiny vials of red liquid. ''O God,'' she
gasped, ''I can't believe all this is my mother.''
Fifty years ago, when Deborah Lacks was still in
diapers, her 30-year-old mother, Henrietta Lacks, lay in a segregated ward of
Johns Hopkins Hospital in Baltimore. The resident gynecologist sewed radium to
her cervix in an attempt to knock out the cancer that was killing her. But
before he finished, and without telling her, he took a small sample of her
tumor and sent it downstairs to Dr. George Gey (pronounced guy), head of tissue
culture research at Hopkins. Dr. Gey had spent almost 30 years collecting cancerous
human cells and trying to make them grow, but until Ms. Lacks came along, they
never did. Though Henrietta died a few months after her radium treatments, her
cells are still living today.
Henrietta's cells -- named HeLa after the first
letters in Henrietta and Lacks -- became the first human cells to live
indefinitely outside the body. They helped eradicate polio, flew in early space
shuttle missions and sat in nuclear test sites around the world. In the 50's,
HeLa cells helped researchers understand the differences between cancerous and
normal cells, and quickly became a standard laboratory tool for studying the
effects of radiation, growing viruses and testing medications. HeLa is still
one of the most widely used cell lines; in fact, this year's Nobel Prize in
Physiology or Medicine was awarded for research in which HeLa cells played a
pivotal role.
Yet it was not until nearly two decades later -- just
before magazines like Jet and Emerge started writing stories about a black
family whose mother had made important contributions to science without their
knowledge -- that anyone in Ms. Lacks's family knew what had happened. Ms.
Lacks, 52, doesn't remember how she heard, but she'll never forget her
reaction: ''I went into shock,'' she said. ''Why didn't they just ask if they
could use her cells?''
If the issue of using patient tissue without
permission wasn't a pressing one in the 50's, informed consent has certainly
become a heated topic today.
''In 1951, they wouldn't have felt like they needed to
ask,'' said Ruth Faden, executive director of the Johns Hopkins Bioethics
Institute. ''It's a sad commentary on how the biomedical research community
thought about research in the 50's, but it was not at all uncommon for
physicians to conduct research on patients without their knowledge or
consent.''
Today, when patients go in for surgery, they're
usually asked to sign a form saying whether their tissues can be used for
research. But, said Lori Andrews, a professor at Chicago-Kent College of Law
and co-author of ''Body Bazaar: The Market for Human Tissue in the
Biotechnology Age,'' that practice doesn't solve an important problem.
''All of us have blood or tissue on file somewhere,''
Ms. Andrews said. ''Today, every drop of blood taken from people, every organ
or biopsy removed by a surgeon, is in the pipeline toward research and
commercialization. Since the 60's, every newborn in the U.S. has been tested
for genetic disorders, and many of their samples are still on file for use in
later research. There are no rules governing who has access to these samples.''
Some bioethicists and lawyers want legislation
requiring researchers to obtain consent before conducting research on any
tissues, including those already in storage. But many research organizations --
the American Society for Investigative Pathology, for example, and the College
of American Pathologists -- have argued that such blanket legislation could
seriously damage scientific progress.
Dr. Mark Sobel, senior executive officer of the
American Society for Investigative Pathology, agrees that informed consent
should be required before new tissues are collected. But to Dr. Sobel, the
millions of tissue samples collected before the current shift toward informed
consent, like Henrietta Lacks's cells, are a special case. Scientists
conducting research on those samples have no way to contact the donors for
permission.
''This is where we want some flexibility,'' Dr. Sobel
said. ''We want recognition that there's a way -- with policies in place for
confidentiality and protecting the patients -- that you can still use these
very, very, very important resources of human tissue. Otherwise, it's going to
impede medical research.''
To Dr. Sobel, using these samples ethically means
protecting patient identity and assuring complete anonymity. Dr. Gey tried to
do this for Ms. Lacks, but rumors began circulating that HeLa stood for someone
named Helen Lane. When a few colleagues of Dr. Gey, who has since died, tried
to correct this error, the Lacks family was thrown into a world of science they
didn't understand.
Ever since Ms. Lacks first heard about her mother's
cells, she has been trying to understand how they could be alive decades after
her death. So she got a notebook, a dictionary and a science book and began
teaching herself about cells, one word at a time.
''A cell,'' she wrote, ''is a minute portion of living
substance.'' She copied one definition after another. ''As long as the cell
receives an adequate supply of food,'' she wrote, ''it will continue to grow
and thrive for the duration of its life cycle.'' Not even Dr. Gey ever
understood precisely why the life cycle of Ms. Lacks's cancer cells has
continued indefinitely.
Within a few years of learning about HeLa cells, the
Lacks family began getting letters from researchers, asking them to donate
blood so scientists could find genetic markers to help identify Henrietta's
cells. But Ms. Lacks remembers differently: ''It was a typed letter, stating we
need samples of the Lacks family to check her blood cells with theirs, to see
if anybody has the same thing that she had,'' she said. Ms. Lacks was in her
late 20's and had always worried that she might die at 31, just like her
mother.
''I cried and cried,'' she recalled. ''I had my two
children, they was babies at the time, and I said 'O God, am I going to make it
past 31?' '' She dodged the researchers at first, because she didn't want to
know whether she had cancer. When she finally decided to take the tests, she
thought she'd get a phone call telling her whether she was going to live or
die. She never heard back from the researchers and soon had the first of what
would become several breakdowns.
Ms. Faden said: ''This could have been a very innocent
misunderstanding. But this is why researchers have to be as straightforward as
possible, because the expectation is that when a doctor wants to do something
to you, it's for your benefit. Physician-researchers need to make this clear by
saying, 'I'm not doing this to help you, I'm doing it to advance science.' ''
Bobbette Lacks, Henrietta Lacks's daughter-in-law,
says that if researchers had told them about HeLa cells, then informed them of
future research, her family would have cooperated. But not now. ''I would never
subject my kids to that,'' Bobbette Lacks said.
This year, the 50th anniversary of Henrietta Lacks's
death, some scientists wanted to honor her contribution. The National
Foundation for Cancer Research had invited Deborah Lacks onstage to thank her
for her mother's cells. But the conference had been scheduled for Sept. 13 and
was canceled after the terrorist attacks. So for now, Ms. Lacks is back to
learning about her mother on her own.
Until Ms. Lacks looked into that freezer filled with
vials earlier this year, she had only read about her mother's cells; she had
never seen them.
Christoph Lengauer, the young cancer researcher who
was showing her around his lab at John Hopkins Oncology Center, leaned over a
microscope, focused it on a single HeLa cell and projected it onto a monitor.
She stared in silence, eyes wide, then sighed. ''I was doing a little bit of
studying on that DNA in my books,'' she said, patting her purse filled with
notes.
Now she is in the process of signing up for basic
courses at a local community center in Baltimore in the hope that they will
lead her toward college. She is not sure what degree she will pursue, but she
knows for sure what she will study: science.
Photos: Deborah Lacks, looking at cancer cells taken
from her mother just before her death 50 years ago. The first human cells to reproduce
indefinitely outside the body, they have helped eradicate polio and flown on
space missions. (Rebecca Skloot)(pg. A15); Above, the HeLa cells, cultured from cancer
cells taken from Henrietta Lacks before she died. At left, Ms. Lacks in the
1940's. (Lacks Family Album); (Keith Porter/Photo Researchers Inc.)(pg. A17)
Source
Published:
Saturday, November 17, 2001
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