IL6 and neoplasm: Comparing IL6 serum level with IL6 expression in ES tumor tissue by RT-PCR or immunohistochemistry in 8 patients, we found that two of three patients with IL6-positive tumors had IL6 serum level ≥ 20 pg/ml at diagnosis, whereas four of five patients with IL6-negative tumors had serum IL6 levels < 20 pg/ml (Table 1, Additional file 2: Figure S2).