Models of Cancer Pain
Bone cancer produces one of the most painful conditions that affects humans and animals. The pain from bone cancer also represents the most common pain in human patients with advanced cancer, because most common tumors, including breast, prostate, and lung cancers, have a remarkable propensity to metastasize to bone.62,113 The first animal models developed to study cancer pain were models of primary and metastatic bone tumors. This advance was followed by the development of nonbone cancer pain models that mimic other types of malignant lesions, including pancreatic cancer and squamous cell carcinoma, as well as, benign, but painful, neuromas. In addition animal cancer pain models have been developed that replicate the pain caused by tumor invasion of peripheral nerves and the pain produced by cancer chemotherapy-related peripheral neuropathy. Finally naturally occurring tumors that arise spontaneously in animals are being used as more natural models of cancer pain. Each of these different models will be discussed in more detail in the following sections.