['We investigated whether microRNA signatures in whole blood samples are associated with acute cellular rejection (ACR) after liver transplantation.', 'Blood samples were collected using Paxgene technology and analyzed by microarrays and quantitative real-time polymerase chain reaction (qRT-PCR).', 'microRNA signatures failed to distinguish between 19 patients with ACR and 16 controls. Let-7b-5p and let-7c were upregulated in a subgroup of patients with ACR during the 6th and 7th postoperative days but failed in an independent validation of 20 patients.'] Do microRNA signatures in peripheral blood fail to detect acute cellular rejection after liver transplantation?