The present invention relates to prognostic methods which are useful in medicine, particularly cancer chemotherapy. The object of the invention to provide a method for assessing Dihydropyrimidine dehydrogenase (DPD) expression levels in tissues and prognosticate the probable resistance of a patient's tumor to treatment with 5-FU based therapies by examination of the amount of DPD mRNA in a patient's tumor cells and comparing it to a predetermined threshold expression level. More specifically, the invention provides to oligonucleotide primer pairs DPD3A and DPD3B and methods comprising their use for detecting levels of Dihydropyrimidine dehydrogenase (DPD) mRNA.