Previously, the dose limiting toxicity of many chemotherapeutic agents was hypersensitivity and neutropenia, but since the former can now be treated with antihistamines or steroids and the latter with granulocyte colony-stimulating factor [45], peripheral neuropathy is the de facto toxicity that limits the administration of many commonly used anti-neoplastic agents [11-14]. The gene discussed is CSF3; the disease is neutropenia.