‘Why Aren’t We All Bacteria?’ Siddhartha Mukherjee Explores the Power of Cells

It’s hard to miss what appears to be dry cleaning hanging on the wall of Siddhartha Mukherjee’s apartment in New York City’s Chelsea neighborhood. The apartment is a sunny, stylish, open space, filled with modern furniture, decorated with sculpture and paintings—and then, in perhaps the most conspicuous spot on the living room, is a brown felt suit with very long pants, draped over a plain wooden hanger. It looks entirely out of place—but it’s not.

The suit is the handiwork of German artist Joseph Bueys, who created the improbable bit of fabric art as a tribute to the nomadic Tatars who, as he would tell the tale, saved his life when he was a Luftwaffe pilot during World War II and his Stuka dive bomber crashed in Crimea, in 1943. The Tatars, ignoring Bueys’ status as one more in a horde of soldiers invading their homeland, wrapped him in felt and animal fat to keep him warm and alive until he recovered from his injuries.

“He was stranded and he was rescued by the locals,” says Mukherjee, “and a lot of his work subsequently had to do with coverings and with felt.”

The tale behind the suit is a singularly human—and humane—one, a bit of individual caregiving in the global slaughter that was World War II. As a work of art, it is very much an apt piece to be displayed in the home of a man like Mukherjee, 52—the Pulitzer Prize-winning author of 2010’s The Emperor of All Maladies: A Biography of Cancer, and the newly released The Song of the Cell. Physician, immunologist, biologist, and an assistant professor of medicine at Columbia University Medical Center, Mukherjee has devoted his life not only to his writing, but to research. He sees the practice of medicine as its own act of mercy, something that is unique to—and a credit to—our often-fractious species.

“It’s a function of humans that we can use reason to alleviate another’s pain,” he says. “Most animals don’t do it. For me to want to relieve your pain or your distress—whether by making a medicine or developing a science—is something both human and quite beautiful.”

Mukherjee’s path to that beautiful place was both a long and rather glittery one—one that saw him excelling academically and, later, scientifically, pretty much anywhere he turned his focus. As a boy in Delhi, India, he attended St. Columbia’s School, where, in 1989, he was awarded the Sword of Honor, the highest academic tribute the school could confer. He went from there to Stanford University as an undergraduate, studying philosophy, computer science, and math, and considered all of those fields as his possible life’s work. Before he could make his choice, he was awarded a Rhodes Scholarship—“That is an offer you can’t refuse,” he says—so he went on to study immunology and biology at Oxford University. Only after graduating, did he decide to study medicine too, earning his M.D. at Harvard Medical School in 2000.

“I did my medical training in reverse,” he says. “I was first trained as an immunologist and then a biologist. That was very critical, because it allowed me not just to think about patients, but to think in terms of what the range of possibilities [to treat them] was scientifically.”

Mukherjee’s specialty was oncology, and he ultimately went to work as a professor of both hematology and oncology at Columbia, which not only steeped him in the science of cancer, but summoned up in him a certain grudging wonder at the malign genius of the cancer cell—a wonder that filled and informed The Emperor of All Maladies.

“Cancer cells have this mechanism by which they can turn off immune system recognition,” he says. “I’ve always been interested in the physiology of cancer. How does it exploit its nutrients, its home, its environment? In the 2000s everyone was talking about how if we sequenced the genome of cancer you would suddenly find all of the keys and all that we would need to do would be to find the locks. But we still don’t have a very good pharmacopeia of drugs to direct against [cancer] mutations. So I can tell a patient, ‘You have a mutation in x, y, z gene.’ And then the patient says, ‘O.K., what are you gonna’ do about it?’ And I say, ‘I don’t know. I don’t have anything to do about it.’”

That hard truth did not mean The Emperor of All Maladies was a hopeless or fatalistic book. Mukherjee dove deeply into the science of the cancer cell and surfaced with new insights into the cellular and molecular mechanisms of malignancies and possible ways to shut those mechanisms down—especially by recruiting the immune system itself as a bigger combatant in the battle against the disease. But there was deeper still to go.

A cancer cell is just a cell after all—one of the 30-plus trillion that make up the human body. In studying the science of individual cells—taking what Mukherjee calls an “atomistic” approach—perhaps there would be answers not just to cancer, but to other diseases too, as well as to the larger secret of biology itself. Life on our 4.5 billion year old planet emerged about 3.7 billion years ago, and for the next two billion years at least it got along perfectly fine as nothing more than single-celled organisms. It was only sometime between 600 million and 1.5 billion years ago that those microscopic, free-floating packets of life came together into algae and plants and trees and fish and dinosaurs and whales and birds and dogs and apes and humans and more. Walt Whitman may have coined the words “I contain multitudes,” but evolution actually performed that act of containment long before the 30 trillion cells that made up the poet himself could come together.

“I think the idea of us being accumulations—cooperative units [of cells]—is a tremendously powerful idea,” says Mukherjee. “The reason the book is called The Song of the Cell is because a song is not just a set of notes; it produces something that’s beyond that set. A sentence or a novel is not a set of words. It’s something that is beyond the words. So I think that as we move ahead in time, we will understand these songs, and they will help us understand physiology.”

Mukherjee structures much of his book in a way that does focus on the individual notes of the cellular song, devoting chapters to The Healing Cell (such as platelets); The Discerning Cell (the immune system’s T cells with their “subtle intelligence”); The Contemplating Cell (the neuron); The Renewing Cell (stem cells); and inevitably The Selfish Cell (cancer). There is a danger of anthropomorphizing, or at least aggrandizing, cells in all of this—and Mukherjee is O.K. with that. At one point in the book he recalls his early work at Oxford, studying T cells under a microscope and whispering to himself, “Like eyes looking back at me.”

His experience mirrors that of the cloth merchant Antonie Van Leeuwenhoek, developer of one of the earliest microscopes—about whom he also writes—peering through his eyepiece in 1674 at a drop of rainwater that he had let stand for a day and finding swimming in it a swarm of tiny “animalcules.”

“This was to me among all the marvels that I have discovered in nature the most marvelous among them all,” Van Leeuwenhoek wrote. “No greater pleasure has yet come to my eye than the spectacle of the thousands of living creatures in a drop of water.”

From all of this, Mukherjee concedes, “It does sound as if cells have agency. It’s not the agency that you and I have [in the form of] sentience. But I think they do have agency in the sense that they’re autonomous. They receive signals, they integrate signals. They then process those signals and send out more signals. They have a desire to survive.”

But it’s in the collective desire—the cooperation among the trillions of freestanding cells to make a single freestanding human—that Mukherjee’s book finds its meaning and its magic. Humans may not be the only multicellular species on the planet, but we’re the apotheosis of multicellularity—the best and the brightest that nature has turned out in the long epochs the chemistry set of our planet has been mixing and mingling its ingredients.

“Bacteria still exist,” Mukherjee says. “And they’re highly effective. They are very good at surviving. So I would ask the question, well, if bacteria are so successful, then why aren’t we all bacteria?”

And he answers that question too. “We aren’t bacteria because at some point in time evolution came to the nonconscious conclusion that in fact, agglomerations of organisms were very effective. In some selected environments—like a New York City apartment—it helps not to be a bacterium. Multicellular organisms can gather food, they can gather information, they can contemplate. Multi-cellular organisms are extraordinarily successful, too.”

Multicellular organisms—wholly unlike unicellular organisms—can do one other thing too: They can care. That business of one human working to alleviate pain or suffering of another is something Mukherjee says we should cherish, and the work he does beyond his writing is very much animated by that imperative.

In India, he has launched a Phase 2B study into the use of CAR-T cells—a specialized type of lab-altered T-cells—to battle cancer in a small sample group of patients. CAR-T cells are extremely complex and costly to produce in the U.S., Mukherjee says, with a course of therapy costing up to $1 million. “We’re trying to produce it at vastly less cost,” he says. “So that has been incredibly gratifying.”

In addition, he is conducting studies at Columbia on ways to treat acute myelogenous leukemia—an extremely deadly form of cancer—using CRISPR gene editing technology. And he is studying how a ketogenic—high-fat, moderate-protein, low-carbohydrate—diet can increase the body’s responsiveness to anti-cancer drugs.

Bacteria can’t do work like that. Individual cells can’t do work like that. But songs of cells—in the case of humans, whole symphonies of cells—can. We are a deeply flawed species, but a deeply good species too. We may fly war planes into other nations’ lands but we swaddle and save the downed pilots who attacked us. It’s in individual cells that the capacity to develop that altruistic behavior begins. It’s in the multitudes of cells that make a person—and the multitudes of people who make a world—that that goodness finds its truest expression.