Dr. Carl June, who directs similar research at the University of Pennsylvania, said the research addressed an important issue by showing that adoptive cell therapy could have an effect on commonly lethal solid tumors.

Another expert, Dr. Michel Sadelain of the Memorial Sloan-Kettering Cancer Center in New York, said the report showed that carefully selected immune cells could be a powerful tool against bile-duct cancer. But he also said it was too soon to tell if the same approach would work for other patients or could be scaled up to treat all those who might need it.

Dr. Rosenberg acknowledged that there were limitations: The technique required highly sophisticated techniques in immunology, and produced a treatment tailored to only one patient. He said his team was working around the clock to streamline the process, and added, “Potentially, if we could reduce the complexity, it’s something that could get out into common usage eventually.”

Researchers have hoped for decades to find some unique marker on cancer cells, something not present on healthy cells, that could be used as a target so that cells of the immune system could home in on it and leave the good ones alone.

The goal has been elusive, but Dr. Rosenberg’s team has helped some patients with melanoma by treating them with immune cells — a type of T cell called a tumor-infiltrating lymphocyte — that were extracted from samples of the patients’ tumors. The team decided to study whether this type of T cell could help people with other types of cancer.

Ms. Bachini learned in 2009 that she had bile-duct cancer, or cholangiocarcinoma. It had already spread to her liver. She had surgery to remove about two-thirds of her liver, but within a few months the disease had turned up in her lungs. She went through one grueling regimen of chemotherapy, then another. She had nerve damage, nausea and hearing loss from the drugs. Her tumors began growing again. She started to cough.

“I knew chemotherapy was not going to kill this,” she said. She quit the drugs.

Searching the Internet for clinical trials, she came across Dr. Rosenberg’s T cell study.