Scientists have created a new method tailored to treat patients' tumors with their own immune systems, which may lead to widespread therapy treatments for 80 percent of all cancers. The National Cancer Institute (NCI) has discovered how to trigger an immune system response to attack against specific types of tumors produced by cancers, which is outlined in the May 9 journal issue of Science.

“Our study deals with the central problem in human cancer immunotherapy, which is how to effectively attack common epithelial cancers,” said Dr. Steven A. Rosenberg, the study’s lead researcher and chief of the Surgery Branch in NCI’s Center for Cancer Research.

All malignant tumors harbor genetic alterations, some of which may lead to the production of mutant proteins that are capable of triggering an antitumor immune response. All cancerous and life-threatening tumors contain within them genetic mutations, which have the ability to turn into mutant proteins. The NCI researchers’ key findings were that these mutant proteins can trigger an antitumor immune response and ultimately a way to fight off cancerous cells.

“The method we have developed provides a blueprint for using immunotherapy to specifically attack sporadic or driver mutations, unique to a patient’s individual cancer,” Dr. Rosenberg said.

This is an innovative form of immunotherapy, in that scientists will manipulate the body’s own immune system to help fight the cancerous tumors. In the past, researchers found through immunotherapy treatments, immune cells could mutate and react well to treat rare cancers such as melanoma and kidney tumors.

The production of tumor-infiltrating lymphocytes (TILS) is what makes immunotherapy’s adoptive cell therapy (ACT) an effective treatment for more than 80 percent of all cancers made of epithelial cells. Epithelial cell cancers, such as digestive, lung, pancreas, and bladder cancers, are the cells that line the body’s internal and external surfaces and amount to 80 percent of all cancers. Previously, scientists did not know if the immune system could create a strong amount of cells — enough to be able to attack epithelial cell cancers, which is why they figured out a way to expand the army themselves.

For the experiment they extracted the strongest tumor-fighting TILs of a 43-year-old woman who had gastrointestinal cancer and wasn’t responding to standard chemotherapy. Scientists then analyzed and identified the cell mutations and helped cultivate and grow them in a laboratory in order to create a larger quantity.

The patient’s cancer had also spread to her lung and livers, but once scientists quadrupled her immune system’s TIL cancer-fighting cells, and transferred the 42.2 billion fighters back into her body, the lung and liver cancers stabilized. Thirteen months later they followed up with another treatment of adoptive cell therapy and her tumors began regression over a six-month period.

This proved to scientists that if a patient’s immune system fighters can be nurtured and grown in a laboratory setting and then implanted back into the patient, tumor regression is possible and another step in the direction of treatment can been taken. This breakthrough could lead to developing individualized immunotherapies for each cancer.

“Given that a major hurdle for the success of immunotherapies for gastrointestinal and other cancers is the apparent low frequency of tumor-reactive T cells, the strategies reported here could be used to generate a T-cell adoptive cell therapy for patients with common cancers,” said Rosenberg.

Source: Rosenberg S, Yang J, Parkhurst M, et al. Cancer immunotherapy based on mutation-specific CD4+ T cells in a patient with epithelial cancer. Science. 2014.