Molecule may signal onset, return of prostate cancer

An immune molecule potentially responsible for the onset, return, and progression of prostate cancer has been discovered by researchers at the Mayo Clinic in Rochester, MN. The report on the B7-H3 molecule appeared in Cancer Research (2007; 67:7893-900).

"This discovery will allow physicians to individualize treatment and observation plans for prostate cancer patients," said lead author Timothy Roth, MD, who worked on the research with Eugene Kwon, MD, and colleagues. "Being able to tell a patient his specific risk after surgery, and perhaps even prior to surgery, will be a huge step forward."

To date, no known highly predictive molecules for prostate cancer had been identified, although certain biomarkers (PSA and prostate-specific membrane antigen) enhanced the ability to diagnose prostate cancer.

The Mayo Clinic study assessed tissue of 338 patients with cancer confined to the prostate who were treated with radical prostatectomy only from 1995 to 1998. Those with the greatest amounts of B7-H3 within the prostate tumors (19.8%) had fourfold risk of cancer progression compared with those with lower levels of B7-H3 in their tumors. Moderate B7-H3 levels were also associated with a marginally greater risk of a recurring tumor (35%).

"Because B7-H3 is present in all prostate cancer tumors, and marked levels predict recurrence, we are able to forecast with much greater certainty the likelihood of cancer progression, regardless of therapeutic intervention," said Dr. Kwon.