Molecular-Genetic Mechanisms Associated With Chemotherapy-Induced Nerve Damage

Objective: Chemotherapy-induced peripheral neuropathy (CIPN) is one of the most debilitating side effects of neurotoxic chemotherapy, and can significantly interfere with patient quality of life (QOL) and the administration of antineoplastic therapy. There is no currently approved safe and effective treatment for CIPN. This protocol will explore the molecular-genetic mechanisms associated with the natural history of CIPN progression by (1) identification of differentially expressed genes and proteins as biomarkers for the onset of CIPN; (2) evaluation of the relationship between biomarkers and the severity of CIPN during the observation period, and (3) determining the relationship between molecular-genetic biomarkers, morphological changes in small nerve fiber and the severity of neuropathic symptoms.

Study population: Cancer patients who plan to receive chemotherapy treatment with either taxane class, vinca alkaloid class, platinum compounds or bortezomib.

Design: This is a prospective, exploratory, natural history study to identify the molecular-genetic mechanisms involved in chemotherapy-induced neuropathy in cancer patients. A physician-based neuropathy scale, patient neurotoxocity questionnaire, and the total neuropathy score will be used to measure the severity of peripheral neuropathy at baseline and after completion of each cycle of chemotherapy infusion. Whole peripheral blood and skin biopsy (only from patients who consent to biopsies) will be collected at baseline and after a subsequent infusion cycle to evaluate gene/protein expression and immunohistochemical labeling at peripheral sites of neuropathic injury. Microarray gene expression analysis will be employed to identify differential regulation of genes involved in the development of CIPN at the different time points compared with gene expression from the baseline samples. Genes of interest will be validated by qRT-PCR to identify novel pharmacological targets to be evaluated in future prospective studies. Protein levels corresponding to the changes in gene expression will be evaluated using ELISA and verified by Western blotting.

Outcome measures: The primary outcome of the study will be the changes in gene and protein expression in the peripheral blood and skin biopsy among cancer patients undergoing chemotherapy. The secondary outcome will be the relationship between the molecular-genetic biomarkers identified and the presence of peripheral neuropathic symptoms and their impacts on patient s QOL.