Insulin-like growth factor-1 as a predictive biomarker for metastatic uveal melanoma in humans

PURPOSE. High expression levels of insulin-like growth factor-1 (IGF-1) receptor were associated with metastatic uveal melanoma (UM). The purpose of this study was to examine the potential of serum IGF-1 in early detection of liver metastasis. METHODS. IGF-1 serum levels were analyzed using enzymelinked immunosorbent assay for 118 subjects in three different groups: 55 disease-free (DF) UM patients who did not develop metastasis within 10 years of diagnosis; 22 metastatic patients; and 41 healthy subjects. Matched pairs univariate analysis was performed for sera of 19 metastatic patients 12 and±months before the diagnosis of metastasis and on the day of diagnosis, both as time groups and normalized levels per patient. IGF-1 levels were compared among groups by analysis of variance and Student t-test. RESULTS. Mean ± SD IGF-1 serum levels for the control, DF, and metastatic groups were 152.48±49.76, 119.92±60.66, and 96.99±56.91 ng/mL, respectively (P < 0.001). Normalized changes in IGF-1 per metastatic patient from 6 months prior to the diagnosis of metastases compared to the day of diagnosis of metastases showed a decreasing trend. CONCLUSIONS. IGF-1 levels in 10-years' disease-free UM patients were significantly lower than those in healthy subjects and were even lower in metastatic patients. IGF-1 levels decreased toward the diagnosis of metastases. Therefore, serum IGF-1 level may be used as a predictive biomarker for metastatic UM when measured repeatedly.