NBC - Seventy percent of people with ovarian cancer will eventually die from the disease. But now doctors say they can use a patient's own immune system to attack the cancer.

Thirty ovarian cancer patients were enrolled in a clinical trial at the University of Pennsylvania.

Doctors used the patients' own tumor cells to create a personalized vaccine.

In some cases, the vaccine was amplified with an immune system booster made from the patient's own blood.

Seventy-five percent of women who received the new treatments, and traditional treatments, saw some benefit.

"This vaccine is made to educate and teach the immune system to identify the cancer cell and hopefully attack it," Lana Kandalaft with the University of Pennsylvania, said.

Researchers say the findings are promising, but they caution that more women need to be studied.

They also need to do more follow-up to look at the potential side- effects of the treatment.