The MDR phenotypeis also the major cause of treatment failure in patientswith malignant lymphoma; however, findings regardingexpression of the MDR1 gene/P-gp in malignant lymphomapatients are inconsistent [16,17,18].Due to the non-clarity surrounding the frequency andclinical relevance of multidrug resistance protein expression,the present study aimed to investigate the expressionof the most common MDR proteins in a group of previouslyuntreated patients with lymphoma—specifically,whether or not these 3 multidrug resistance proteins wereexpressed and their impact on clinical outcome. This evidence concerns the gene PGP and lymphoma.