EDN1 and cancer: In mice implanted with fibrosarcoma cells into and around the calcaneus bone, ET-1 injected into the receptive fields of C-nociceptors innervating the hind paw evoked an increase firing rate in control and tumor-bearing mice, whereas application of the ETA receptor antagonist BQ-123 attenuated tumor-evoked spontaneous activity and sensitization to heat in C-nociceptors of tumor-bearing mice.33 Thus, ET-1 seems to contribute to peripheral sensitization in a variety of cancers, including bone cancer.