The methods of the invention detect in a qualitative or quantitative fashion drug-resistance RNA and DNA in blood plasma, serum, and other bodily fluids. The methods of the invention thereby enable the assessment of drug resistance in a neoplasm without the requirement of a tissue biopsy. The inventive methods are useful for the evaluation, monitoring, and selecting of drug treatment regimens, and for determining a predisposition for or prognosis of chemoresistant neoplastic disease.