Soon, personalised ovarian cancer vaccines

Scientists, including one of Indian-origin, have found a new way to identify protein mutations in cancer cells that paves the way for development of personalised vaccines to treat patients with ovarian cancer.
"This research will serve as the basis for the first ever genomics-driven personalised medicine clinical trial in immunotherapy of ovarian cancer, and will begin at the University of Connecticut Health Center this fall," said Dr Pramod Srivastava, director of the Carole and Ray Neag Comprehensive Cancer Center at UConn Health and one of the principal investigators on the study.
Dr Angela Kueck, a gynecological oncologist at UConn Health, will run the initial clinical study, once it is approved by the US Food and Drug Administration (FDA).

The research team will sequence DNA from the tumours of 15 to 20 women with ovarian cancer, and use that information to make a personalised vaccine for each woman.
The researchers focused their clinical trial on patients with ovarian cancer because the disease usually responds well to surgery and chemotherapy in the short term, but often returns lethally within a year or two.
That gives researchers the perfect window to prepare and administer the new therapeutic vaccines, and also means they may be able to tell within two years or so whether the vaccine made a difference.

If the personalised vaccines prove to be safe and feasible, they'll design a Phase II trial to test its clinical effectiveness by determining whether they prolong patients' lives.

In order for the immune system to attack cancers, it first has to recognise them. Every cell in the body has a sequence of proteins on its exterior that acts like an ID card or secret handshake, confirming that it's one of the good guys. These protein sequences, called epitopes, are what the immune system 'sees' when it looks at a cell.
Cancerous cells have epitopes, too. Since cancer cells originate from the body itself, their epitopes are very similar to those of healthy cells, and the immune system doesn't recognise them as bad actors that must be destroyed.
"We want to break the immune system's ignorance," Srivastava said.

For example, there could be 1,000 subtle changes in the cancer cell epitopes, but only 10 are "real," meaning significant to the immune system.
To find the real, important differences, researchers took DNA sequences from skin tumours in mice and compared them with DNA from the mice's healthy tissue.
Srivastava's team looked at how different the cancer epitopes were from the mice's normal epitopes.
When mice were inoculated with vaccines made of the cancer epitopes differing the most from normal tissue, they were very resistant to skin cancer.