Malignant mesotheliomas reportedly secrete interleukin-6 (IL-6) which augments production of vascular endothelial growth factor (VEGF) from mesothelioma cells.
Neither anti-IL-6 antibody nor rhuIFN alpha had a direct growth-inhibitory effect on the AB22 mesothelioma cell line in vitro, however, in vivo rhuIFN alpha treatment of mice inoculated with AB22 cells attenuated both IL-6 mRNA expression in the tumours and serum IL-6 levels, ameliorated the depression of lymphocyte activities, and enhanced the number of tumour-infiltrating lymphocytes and macrophages.