Vaccines hold promise for breast cancer patients

Elizabeth Mittendorf, M.D., Ph.D., abandoned plans to become a pediatrician when she fell in love with the knowledge and skills a surgeon has.

“Surgeons can address just about anything that comes through a hospital door,” says the assistant professor in MD Anderson’s Department of Surgical Oncology. “I wanted to have that ability.”

It wasn’t until after her clinical residency that she could pursue research questions — like how vaccines might arm the immune system to fight cancer. Then, after a three-year MD Anderson fellowship, which broadened her scientific base, she set up her own lab and continued her vaccine research.

“I became interested in vaccines and breast cancer patients for several reasons while I was in the Air Force,” she says. “I like the biology of the disease; I like working with breast cancer patients; and I like the multidisciplinary approach. Plus, this is a field that’s conducive to research, especially as a surgeon.”

The breast cancer vaccine she’s evaluating is a hybrid modified to increase its potency.

“It educates the immune system to recognize HER2 [an oncoprotein that promotes tumor growth] as an invader,” says Mittendorf, who is the trial’s national principal investigator. “By introducing it into women who have had breast cancer, our goal is to instruct the immune system to immediately recognize any recurring cancer cells and orchestrate an attack.”

Mittendorf is gratified and encouraged by results from a clinical trial that showed a powerful immune response in women with varying levels of HER2 expression and that the vaccine may have the ability to decrease recurrence rates.

Patrick Hwu, M.D., wants to use his “flash of time” well.

“Life is short,” says the professor and chair of MD Anderson’s Department of Melanoma Medical Oncology, “We only have a flash of time to make an impact and help people. For me, cancer research puts meaning into that time.”

Knowing the power of the immune system, he wanted to see if it could be activated against cancer.

“Knowledge of the immune system has improved people’s health through the decades,” he says. “Vaccines stimulate the immune response against infectious disease. In fact, vaccines have saved more lives than antibiotics. We now want to develop methods to stimulate the immune response against cancer.”

He describes his research in military terms. The T-cells of our immune system fight foreign invaders. They act like tanks that can blow holes in cancer cells. Immune strategies work in a number of ways. Vaccines can stimulate the proliferation of tumor-fighting tanks. Antibodies can take the “brakes” off the tanks, and with T-cell transfer therapy, researchers grow large numbers of these tanks in the lab, then reinfuse them into patients.

“Immune therapies can be durable because T-cells can live for years in the body,” Hwu says.

The future is in the rational combination of therapies, such as combining vaccines with interleukin-2, a growth factor for T-cells.

The results show that patients with advanced melanoma have improved response rates and progression-free survival with this combination. Hwu is working on other combinations of agents, such as targeted therapies and immunotherapies that may further improve upon these initial results.