An immune molecule called B7-H3 on the surface of prostate cancer cells may be useful in predicting prostate cancer progression after radical surgery, according to investigators.
“This discovery will allow physicians to individualize treatment and observation plans for prostate cancer patients,” said lead study author Timothy Roth, MD, a urology resident at the Mayo Clinic in Rochester, Minn.
Unlike PSA, B7-H3 stays attached to the surface of prostate cancer cells and does not appear to migrate. This could make B7-H3 an attractive therapeutic target. The investigators speculate that B7-H3 kills or paralyzes immune cells that are trying to attack the cancer.
“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 co-investigator Eugene Kwon, MD, a senior investigator and urologist at Mayo.
Dr. Roth’s group examined tissue from 338 consecutive patients who had localized prostate tumors; all underwent radical prostatectomy. All prostate tumor specimens showed some degree of B7-H3 expression. Patients with marked expression of B7-H3 (19.8% of subjects) were more than four times as likely to experience cancer progression compared to patients with weak expression, according to a report in Cancer Research (2007;67:7893-7900). Moderate expression of B7-H3 was associated with a nonsignificant 36% increased risk of progression.
The authors concluded: “Our study supports B7-H3 as a promising marker to improve prostate cancer diagnosis, prognostic assessment, and targeted treatment.”