Serum concentrations of soluble interleukin-2 receptor in patients with malignant brain tumors

BACKGROUND AND OBJECTIVES: Interleukin-2 receptor alpha (IL-2Ralpha) can combine with IL-2 firmly, and soluble IL-2Ralpha (sIL-2Ralpha) is elevated in sera from patients with various types of cancers. To investigate the role of this receptor, we studied the changes of serum sIL-2Ralpha in patients with malignant brain tumors. METHODS: SIL-2Ralpha was measured in 100 patients with malignant brain tumors (63 cancer metastasis, 16 malignant gliomas, 21 malignant lymphomas), and 51 patients with cancer who had no distant metastasis such as brain metastasis. RESULTS: In patients with 35 metastatic brain tumors from lung cancer, the levels of sIL-2Ralpha were not significantly different from levels in normal volunteers (311 +/- 62.4 U/ml). In patients with 25 metastatic brain tumors from lung adenocarcinoma, the mean level of serum sIL-2Ralpha was 352 +/- 94.0 U/ml. These same patients showed high levels of serum sIL-2Ralpha (492 +/- 101 U/ml) with regional lymph nodes metastasis. Serum sIL-2Ralpha concentration in 16 patients with malignant glioma varied greatly with the mean concentration of 328 +/- 192 U/ml. In 5 of 16 patients with malignant glioma, we could detect the significant increase of serum sIL-2Ralpha concentration from early stage of recurrence. CONCLUSIONS: Serum levels of sIL-2Ralpha could be a useful immunological marker in patients with malignant brain tumors.