Protein S-100 linked to melanoma recurrence

Higher levels of a protein called S-100 in patients with melanoma may correlate with a higher risk of having the disease return, say researchers at the University of Pittsburgh Cancer Institute (UPCI), who presented their findings today at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago.

The study is Abstract number 8506 in the ASCO proceedings.

The study evaluated and tested serum samples from 103 patients who were treated with high-dose interferon, a standard immunotherapy treatment for melanoma, an average of eight years prior. The disease recurred in 64 of the patients within an average of 30 months. When the researchers examined levels of S-100 in the serum samples, they found that the higher the level of the protein, the greater likelihood the patient's disease had returned.

"Melanoma patients who initially respond well to treatment with interferon are at high risk of their cancer recurring," said John Kirkwood, M.D., principal investigator of the study, professor of medicine at the University of Pittsburgh School of Medicine and director of the Melanoma Center at UPCI. "We know that only 30 percent of these patients benefit from treatment long-term. The goal of our study was to identify better predictors of who will benefit most from treatment with interferon and who is most at risk of their cancer returning."

The study also found that patients who survived longer showed increased evidence of an autoimmune response to treatment with interferon. Autoimmunity is an immune response against the body's own tissues.

"With further study, we hope to learn more about the role of S-100 in melanoma survival," said Joseph Stuckert, medical student at the University of Pittsburgh School of Medicine who is presenting the study at ASCO. S--100 may be an important key to better stratifying patients into those more or less likely to relapse."

According to Stuckert, the next step in the research is to identify predisposing factors that may make patients more likely to develop autoimmunity and to further examine the role of S-100 as a potential biomarker for melanoma.