Cancerous tumours vary significantly in their response to chemotherapy agents. Currently, it is difficult to reliably assess the level of tumour responsiveness to a chemotherapy regimen during or post-administration. Biomarkers of tumour sensitivity to chemotherapy agents have hitherto been unknown. Such a biomarker would expedite identification of nonresponsive patients, who may then switch to other, possibly more effective regimens. The present invention provides a method for determining tumour responsiveness to a chemotherapy agent, wherein RNA is isolated from tumour cells of a patient before, during, and after chemotherapy. The quality of the RNA can be determined by capillary electrophoresis and assignment of an RNA integrity number (RIN). RIN values during and/or after chemotherapy are inversely proportionate to the level of tumour responsiveness. The tumour RIN is an easily accessed biomarker of tumour responsiveness to chemotherapy. The tumour RIN may also be used to assess the efficacy of a chemotherapy regimen.
