SERUM INTERLEUKIN-6 LEVELS IN METASTATIC RENAL-CELL CARCINOMA BEFORE TREATMENT WITH INTERLEUKIN-2 CORRELATES WITH PARANEOPLASTIC SYNDROMES BUT NOT PATIENT SURVIVAL

Purpose: We sought to determine the frequency of interleukin-6 (IL-6) expression in renal cancer cell lines, the frequency of the detection of IL-6 in the serum of patients with metastatic renal cell carcinoma, whether serum IL-6 level correlates with the development of paraneopl astic syndromes and whether serum IL-6 level in patients with metastat ic renal cancer correlates with response to treatment with interleukin -2 (IL-2) or patient survival. Materials and Methods: Conditioned medi a from 21 cell lines from 20 patients were examined for IL-6. We ident ified 2 matched groups of patients with metastatic renal cancer (30 re sponders and 29 nonresponders) to IL-2 based immunotherapy. Stored pre treatment serum specimens were evaluated for IL-6. Medical records wer e reviewed to determine the presence of paraneoplastic syndromes. Resu lts: IL-6 was detected in 19 of 21 renal cancer cell lines (90%) obtai ned from 20 patients with metastatic renal cancer as well as in the se rum of 33 of 59 patients (56%) with metastatic renal cell carcinoma. A significant association between serum IL-6 level and anemia (p = 0.00 32), elevated platelet count (p = 0.01), decreased albumin (p = 0.034) and elevated alkaline phosphatase (p = 0.04) was found. A trend was n oted of the association of increased serum IL-6 level and fever (p = 0 .051). No correlation was found between pretreatment serum IL-6 level and survival or response to IL-2. Conclusions: IL-6 was frequently sec reted by renal cancer cell lines but it was only present in the serum of approximately half of the patients with metastatic renal cancer, El evations of serum IL-6 were associated with paraneoplastic manifestati ons frequently seen in patients with renal cancer, including anemia, t hrombocytosis, decreased albumin and elevations of alkaline phosphatas e (Stauffer's syndrome), A weak relationship was noted between serum I L-6 level and fever but none was noted between that and survival or re sponse to IL-2.