ABCB1 and cancer: Recent data indicate that Sorcin participates in several processes that might contribute to MDR in human cancers, such as drug efflux regulation, apoptosis modulation and epithelial-to-mesenchymal transition (EMT) control.8, 9 Conflicting results are in literature on the effect of Sorcin overexpression and silencing on MDR1 expression and activity.10, 11, 12, 13 A complete understanding of the mechanisms and pathways by which Sorcin contributes to the MDR phenotype of tumor cells and an assessment of the overall diagnostic and therapeutic potential of sorcin in MDR are still missing.