Of the ten cytokines examined, the levels of IL (interleukin)4, IL6, IL10, IL12 (IL12p70) and TGFB1 (transforming growth factor beta-1) increased with increasing peritoneal cancer burden (p < 0.005 by Kruskal–Wallis test) although the subgroup analyses mostly were not significant, whereas the levels of IL2, IL5, IL17A (IL17A homodimer), IFNG (interferon-gamma) and TNF (tumor necrosis factor) did not. This evidence concerns the gene IL6 and peritoneum cancer.