Neuronal signal transducer gp130 plays a role in tumor-induced mechanical hyperalgesia. (A) Mechanical threshold after tumor induction in the hind-paw of gp130fl/fl (open triangle n = 17) and SNS-gp130-/- (black square, n = 11) mice. After inoculation with tumor cells mechanical thresholds dropped by 30% in both mouse strains, but in SNS-gp130-/- mice the degree of hypersensitivity was significantly reduced in comparison to gp130fl/fl mice at day 1, 6, 8, and 10 (* p < 0.05, ** p < 0.01, *** p < 0.001; ANOVA). (B, C) Mechanical von Frey thresholds of fibers recorded in in vitro skin-nerve preparation from gp130fl/fl and SNS-gp130-/- mice at 7 to 10 days post inoculation. Nociceptors from gp130fl/fl mice projecting into tumor area showed lower thresholds (≤ 22.6 mN, n = 28) than fibers innervating healthy skin (n = 66, ** p < 0.01; χ2-test), whereas no difference was found between healthy and tumor skin in SNS-gp130-/- animals.