By Ashley Hayes

Actor Mark Harmon, who stars on the television show "NCIS," appears in a new public service announcement aimed at increasing awareness about cancer immunotherapy, or mobilizing one's own immune system to fight cancer.

The PSA, from Stand Up to Cancer and the Cancer Research Institute, debuted Thursday.

Harmon participated in the announcement on behalf of friends who have battled cancer. "Cancer research is extremely important to me," the two-time Emmy nominee said in a statement.

"I don't know anyone who hasn't been affected by cancer in some way or another. I'm here ... to highlight the unbelievable work that CRI and SU2C are doing to advance the field of cancer immunology."

Immunotherapy treatments involve drugs that train the immune system to recognize and kill cancer cells.

Two new studies presented last month at the American Society of Clinical Oncology conference -- the largest convergence of cancer experts worldwide -- involving immunotherapy showed what society President Dr. Sandra Swain called "significant progress."

Similar studies were presented at the 2012 meeting.

In December, SU2C and the Cancer Research Institute announced that they were forming a Cancer Immunology Translational Research Dream Team to explore the relationship between cancer and the immune system, using $10 million in funding over three years. Scientists on the "dream team" represent eight institutions nationwide.

"The research that CRI and SU2C are doing shows us that with the help of immunotherapy, our bodies' own natural defenses can fight cancer," Harmon said.

"We've all seen people suffer through different kinds of treatments for this disease, but these advances in immunotherapy have the potential to significantly change cancer treatment as we know it. It's important for people to learn about these discoveries."