Genomics and Liver Transplantation: Genomic Biomarkers for the Diagnosis of Acute Cellular Rejection.

Acute cellular rejection (ACR) is a common complication in liver transplant recipients (LTxR), especially within the first 12 months, and is associated with increased morbidity and mortality. While abnormalities in standard liver biochemistries may raise the clinical suspicion for ACR, it lacks specificity, and invasive liver biopsies are required for definitive diagnoses, which is associated with numerous risks. Biomarker discovery for minimally-invasive tools for diagnosis and prognostication of ACR after liver transplantation (LTx) has become a rapidly evolving field of research with a recent shift in focus to omics-based biomarker discovery. Although none are yet ready to replace the standard of care, there are several promising minimally-invasive, blood-derived biomarkers for the diagnosis of ACR in LTxR that are under intensive research. These omics-based biomarkers, encompassing DNA, RNA, proteins, and metabolites, hold tremendous potential. Some are likely to become integrated into ACR diagnostic algorithms to assist clinical decision making with a high degree of accuracy that is cost effective and reduces or even obviates the need for an invasive liver biopsy.