Analysis of transition metals in glioblastoma tumor and plasma samples.

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e14029 Background: Transition metals such as copper, iron, zinc, and manganese are known to play essential roles in human physiology as evidenced in conditions where these metals are dysregulated. The role of transition metals in glioblastoma biology has been largely understudied. Here we investigated whether plasma and tumor transition metal content is associated with glioblastoma patient outcomes. Methods: Transition metal content was measured in 31 glioblastoma tumor samples, 21 of which had matched plasma samples, using inductively coupled plasma mass spectroscopy (ICP-MS) or inductively coupled plasma atomic emission spectroscopy (ICP-AES). Concentrations of transition metals in plasma and tumor were then then correlated with clinical parameters including median overall survival (mOS) as well as plasma cytokines. Results: Spearman correlation analysis of transition metals in glioblastoma tumor samples found that tumor manganese and tumor zinc (R = 0.52, p = 0.0048) as well as tumor copper and tumor zinc (R = 0.36, p = 0.038) were positively correlated. Plasma transition metal content did not correlate with tumor transition metal content. Kaplan-Meier and Cox regression survival analysis between high and low expressors of each respective transition metal, separated at the median, revealed that high plasma iron content was associated with prolonged survival (median overall survival: 30.1 vs 12.4 months, P = 0.0036). Plasma from glioblastoma patients in the high plasma iron group had increased levels of IFN-β (10.91 pg/mL vs 7.43 pg/mL, P = 0.004). Plasma or tumor concentrations of copper, zinc, or manganese did not associate with survival. Conclusions: Increased plasma iron content is associated with prolonged survival as well as increased plasma IFN-β levels, suggesting a possible link between iron and immune responses in glioblastoma patients.