Elevated levels of soluble interleukin-2 receptor in serum of patients with hematological or non-hematological malignancies

We measured the levels of soluble interleukin-2 receptor (sIL-2R) in the serum of 53 patients with hematological malignancies (14 with acute leukemia, 10 myeloproliferative disorders, 21 non-Hodgkin's lymphoma and 8 multiple myeloma), 40 with non-hematological solid malignancies (24 with lung cancer, 11 digestive system cancer and 5 other cancers) and 95 healthy subjects as a control using an enzyme-linked immunosorbent assay. Both hematological and non-hematological neoplasms showed significantly higher sIL-2R levels than normal subjects (p < 0.01). However, compared to solid malignancies, hematological neoplasms displayed a wide range of sIL-2R levels and extremely elevated values of sIL-2R were seen in certain cases. These results seem to suggest that sIL-2R levels may serve as one of non-invasive markers of differential diagnosis for patients with bulky mass lesions between hematological and solid malignancy.