C-Reactive Protein: An Emerging Biomarker for Estimating Melanoma Prognosis

Protein may potentially offer a future therapeutic target.

Biomarkers in cancer have an important role in determining a patient's prognosis, and may also be important in designing targeted therapies. For instance, the KRAS gene is a known negative prognostic biomarker in many types of cancers, and agents are under development to target this mutation.

Other prognostic indicators, such as the marker of inflammation C-reactive protein (CRP), may have a similarly important role, not only in determining the prognosis of melanoma, but potentially as a future therapeutic target.

In a 115-person study of patients with melanoma conducted by researchers at several institutions across the United States, investigators assessed levels of CRP as it related to survival and clinical outcomes through Kaplan-Meier and Cox regression statistical techniques. Patients enrolled in the study underwent sequential blood draws over up to 14 years of follow-up.

Researchers found that higher levels of CRP correlated with inferior overall survival. With each 1-unit logarithmic increase in CRP levels, the risk of mortality increased by 44% on average, although the lower and upper bounds of the 95% confidence interval indicate that the increase is likely no less than 30% and likely no more than 59%.

Researchers found a clinically important difference in survival and response rates at the CRP level of 10 mg/L. Patients with levels higher than this experienced poorer overall survival, regardless of the stage of melanoma. In fact, the CRP marker was an even more reliable indicator of survival likelihood than the stage of the disease. For instance, patients with stage III/IV disease with a low CRP were at lower risk of death than patients with stage I/II disease who had a high CRP level (ie >10 mg/dL).

These findings indicate that current staging systems are missing a critical part of the prognostic puzzle. Although future studies will need to be conducted to verify the findings of this 115-patient study, CRP may have an important future role in the staging of melanoma and in selecting patients for treatment with targeted agents.

In their conclusion, investigators wrote, “CRP measurement should be considered for incorporation into prospective studies of outcome in patients with melanoma and clinical trials of systemic therapies for those with melanoma.”

Reference

Fang S, Wang Y, Sui D, et al. C-reactive protein as a marker of melanoma progression. J Clin Oncol. 2015;33(12):1389-1396.