Scientists use patient’s tumor to form cancer vaccine

WASHINGTON - Scientists have come up with a novel way to approach cancer treatment.

They say that a new process for creating a personalized vaccine may become a crucial tool in helping patients with colorectal cancer develop an immune response against their own tumors.

This dendritic cell (DC) vaccine, developed at Dartmouth, was used after surgical resection of metastatic tumors to try to prevent the growth of additional metastases.

“The results of the study suggest a new way to approach cancer treatment,” said Richard Barth Jr., Chief of General Surgery at Dartmouth-Hitchcock Medical Center and a member of the Gastrointestinal Clinical Oncology Group at Dartmouth-Hitchcock Norris Cotton Cancer Center, who is the study’s principal investigator.

“Basically, we’ve worked out a way to use dendritic cells, which initiate immune responses, to induce an antitumor response.”

Dendritic cells are critical to the human body’s immune system, helping identify targets, or antigens, and then stimulating the immune system to react against those antigens.

The new research grew dendritic cells from a sample of a patient’s blood, mixed them with proteins from the patient’s tumor, and then injected the mixture into the patient as a vaccine.

The vaccine then stimulated an anti-tumor response from T-cells, a kind of white blood cell that protects the body from disease.

In the study, Barth first operated on 26 patients to remove tumors that had spread from the colon to the liver. While some of these patients would be expected to be cured with surgery alone, most of them would eventually die from tiny metastases that were undetectable at the time the tumors were removed from the liver.

The DC vaccine treatment was given one month after surgery. The results were that T-cell immune responses were induced against the patient’s own tumor in more than 60pc of the patients.
he patients were followed for a minimum of 5.5 years.; Five years after their vaccine treatment, 63pc of the patients who developed an immune response against their own tumor were alive and tumor-free. In contrast, just 18pc of the patients who did not develop an immune response against their own tumor were alive and tumor-free.

“We showed that a tumor lysate-pulsed DC vaccine can induce immune responses against the patient’s own tumor in a high proportion of patients,” stated Dr. Barth, who has been investigating DC-based vaccines in mice and patients for more than 10 years.

The study has been described in the journal Clinical Cancer Research. (ANI)