In order to learn more about the first CRISPR clinical trial in the United States, I traveled to Philadelphia, where I found people living with inequality and ongoing disruptions. I stayed with a friend in Fishtown, a neighborhood undergoing rapid gentrification. As we chatted about how CRISPR could transform science and medicine, my friend told me about unsettling dynamics that were leaving uneven marks on the landscape. His neighbor's house had just sold for $750,000. According to Forbes, Fishtown was “America's hottest new neighborhood” and had seen a recent “stampede of Millennials, yuppies, hipsters, entrepreneurs, and empty nesters.” Evidence of gentrification—new cafes, coffee shops, and bars—sat uneasily alongside signs of abject poverty, despair, and open violence. Orange caps from hypodermic syringes littered the ground.

Grabbing an Uber, I took a ten-minute ride south on Interstate 95 to the Sean Parker Institute for Cancer Immunotherapy, situated in a gleaming new high-rise. It was part of a biomedical innovation hub within the Penn Medicine campus, across a bridge from downtown Philadelphia, with a freshly constructed bike path and greenway framing views of the river. As my Uber driver dropped me off, valet parking attendants catered to patients, while physicians, nurses, and family members sipped Starbucks coffee inside a spacious atrium.

The Cancer Survivor Hall of Fame was up on the ninth floor. Each of the people pictured had engaged in a heroic struggle, brushing past terminal diagnoses and financial barriers, in pursuit of lifesaving experimental medicine. A smiling woman was pictured next to Philadelphia's iconic LOVE sculpture, her IV bags, tubes, and electronic monitor on a portable stand. She had flown in from California to participate in an experimental trial. William Ludwig, a sixty-four-year-old retired corrections officer from New Jersey, was photographed with a handwritten sign: “I was patient #1 of CART-19 & all I got was this T-shirt and REMISSION!!” Another cancer survivor, Doug Olson, was smiling and sweaty after running a half marathon with his son.

A twelve-year-old girl named Emily Whitehead was clearly the darling of the scientists who work at Penn Medicine. She was pictured, smiling, with a sign: “I am 5 years cancer free!” Shortly after she was treated with a gene therapy in 2012, Emily traveled to Washington.