Looking at these data, tumour-specific expression of ENT1, RRM1 or ERCC1, or some DNA repair genetic polymorphisms appear to be promising indicators of prognosis in patients receiving gemcitabine chemotherapy, although prospective pharmacogenetic-based clinical studies will be necessary to clarify the usefulness of these biomarkers in patients receiving gemcitabine-based chemotherapy. The gene discussed is ERCC1; the disease is neoplasm.