In 1984, researchers begin to understand why Henrietta’s cells are immortal. A virologist named Harald zur Hausen discovers an STI called Human Papilloma Virus (HPV), some strains of which may cause cervical cancer. HeLa tests positive for a strain called HPV-18. Rebecca explains that there are over one hundred strains of HPV, and that thirteen of these cause cancer. HPV-18 is one of the most virulent. This research eventually leads to an HPV vaccine.
At last, the secret of Henrietta’s immortality begins to unravel; at its heart sits HPV, a cancer-causing virus for which scientists have since developed a vaccine—thanks in large part to HeLa. It is tragic, and yet appropriate, that HeLa would help provide a vaccine for the very virus that caused Henrietta’s tumors and eventually killed her.
In Henrietta’s case, HPV inserted itself into her DNA and turned off a gene that suppresses tumors. Scientists still don’t understand, however, why she then produced such virulent cells. Rebecca speaks to other researchers, none of whom can fully explain the growth of Henrietta’s cells.
Even now, though, a mystery remains as to why these cells in particular are so strong—leaving room in the narrative for some spiritual or metaphysical explanation.
Henrietta’s family, on the other hand, has many theories. Her sister Gladys believes that the cancer was an affliction to punish Henrietta for leaving Gladys to care for their elderly father. Cootie believes that spirits caused the disease. Sadie, meanwhile, wonders whether water from Turner Stationmight have infected Henrietta.
Skloot presents the Lacks family’s theories without comment or skepticism—she has a deep respect for the Lackses’ opinions when it comes to Henrietta, particularly considering how mistreated and misinformed they have been.
Rebecca recalls that every decade has made innovations due to HeLa. In the eighties, a molecular biologist named Richard Axel alters HeLa cells in order to make them susceptible to HIV, determining how exactly the virus attacks cells. This research attracts the eye of Jeremy Rifkin, an activist who believes that scientists should not be allowed to alter DNA. Rifkin eventually sues to stop Axel’s research, but the suit is dismissed.
As science develops, HeLa continues to prove relevant and useful—but wherever it goes, it seems, controversy follows. In the eighties, this controversy takes the form of whether or not scientists should alter DNA—a debate that continues on to the present day.
Two other scientists begin to theorize that HeLa cells may no longer be human, arguing that they have gone through millions and billions of generations of cells since the first sample was taken. During this time, they assert, the cells have evolved.
The many different theories about HeLa—even among the scientific community—prove how little we know, even now, about the mechanisms of cell culturing. Despite having been cultured in the 50s, HeLa still contains mysteries.
Researchers begin to wonder whether HeLa cells may indeed contain clues about immortal life. Rebecca explains that normal human cells cannot grow indefinitely; they divide a set number of times and then die. From their HeLa research, scientists know that cancer cells can divide indefinitely. They connect this phenomenon to a section of the chromosome called the telomere, which shortens each time a cell divides. As cells become older, the telomeres become shorter, and the cell stops dividing. There is an enzyme called telomerase that rebuilds telomeres, however, and in the case of HeLa, telomerase constantly regenerates the telomeres of Henrietta’s chromosomes, enabling HeLa to outlive almost all other cells.
Skloot means to remind us of just how vital HeLa has proved in the role of scientific discovery, even up to the present day. The idea of extending human life by manipulating DNA sounds like something out of science fiction; and yet when it comes to HeLa, it appears that the possible may well become possible.