Combination of serum 5-S-cysteinyldopa, melanoma inhibitory activity and IL-8 improves the diagnostic accuracy of malignant melanoma compared with individual markers.

Early diagnosis of malignant melanoma is critical for effective treatment and reduced patient mortality. However, current clinical and histological variables show limited accuracy in diagnosis. Serum or urine level of 5-S-cysteinyldopa (5-S-CD) is a commonly used melanoma biomarker in Japan owing to its increased sensitivity compared with other melanoma markers. However, its use as a diagnostic marker has shown some limitations. Therefore, here we examined the combination of 5-S-CD with melanoma inhibitory activity, which showed sensitivity in detecting melanoma comparable with that of 5-S-CD, and interleukin-8, a cytokine linked with melanoma progression, in a cohort of Japanese patients with melanoma. Our results revealed that the triple combination of 5-S-CD, melanoma inhibitory activity, and interleukin-8 showed high diagnostic accuracy in detecting melanoma compared with each of the individual factors. Importantly, the triple marker showed specificity and utility in detecting early-stage melanoma. Our results suggest the utility of the triple marker as a diagnostic biomarker for melanoma patients.