Impact of tissue source type on gene expression profiles of normal human kidney

Normal human tissue is critical as a reference control in biomedical research. Yet access to high quality human tissue can be challenging due to clinical, logistical and ethical issues. Possible human normal tissue source types include non-transplantable tissues from organ donors (OD), post-mortem cadaveric tissues (CAD), and surgical resections of normal adjacent tissues (NAT) in cancer patients. But few studies have comprehensively explored the impact of these source types on the biological profile of the tissue. We assembled a panel of human normal kidney tissue from 91 donors representing OD, CAD, and NAT, as well as the matching kidney tumor. Histopathologic and molecular profiles by RNASeq analysis revealed clear differences between tumor and normal samples, regardless of the source type. Among the normal samples, there was a general similarity between source types, with little evidence of a field cancerization effect in the NAT. Differential gene expression and enrichment analyses indicated differences among source types in immune system and inflammatory processes, response to extracellular stimuli, ion transport and metabolic pathways. We conclude that all three normal source types are suitable for reference kidney control samples, but important differences are to be noted for particular research areas and tissue banking strategies. 111 samples (28 from cadaveric, 22 from organ donor, 30 from normal adjacent tissue and 31 matching kidney tumor)