# Advanced Omics and Radiobiological Tissue Archives: The Future in the Past
###### Abstract  
Archival formalin-fixed, paraffin-embedded (FFPE) tissues and their related diagnostic records are an invaluable source of biological information. The archival samples can be used for retrospective investigation of molecular fingerprints and biomarkers of diseases and susceptibility. Radiobiological archives were set up not only following clinical performance such as cancer diagnosis and therapy but also after accidental and occupational radiation exposure events where autopsies or cancer biopsies were sampled. These biobanks provide unique and often irreplaceable materials for the understanding of molecular mechanisms underlying radiation-related biological effects. In recent years, the application of rapidly evolving \"omics\" platforms, including transcriptomics, genomics, proteomics, metabolomics and sequencing, to FFPE tissues has gained increasing interest as an alternative to fresh/frozen tissue. However, omics profiling of FFPE samples remains a challenge mainly due to the condition and duration of tissue fixation and storage, and the extraction methods of biomolecules. Although biobanking has a long history in radiation research, the application of omics to profile FFPE samples available in radiobiological archives is still young. Application of the advanced omics technologies on archival materials provides a new opportunity to understand and quantify the biological effects of radiation exposure. These newly generated omics data can be well integrated into results obtained from earlier experimental and epidemiological analyses to shape a powerful strategy for modelling and evaluating radiation effects on health outcomes. This review aims to give an overview of the unique properties of radiation biobanks and their potential impact on radiation biology studies. Studies recently performed on FFPE samples from radiobiology archives using advanced omics are summarized. Furthermore, the compatibility of archived FFPE tissues for omics analysis and the major challenges that lie ahead are discussed.  
FFPE; ionising radiation; radiobiological archive; biobank; cancer; omics; RNA sequencing +
Footnote †: journal: Medical  
are the only source of biomaterial available, can be used to understand the molecular mechanisms involved in the biological effects of radiation exposure,  
Advances in high-throughput molecular analysis in recent years have revolutionised our knowledge of biological processes. Global analyses of proteins, RNA, genes, metabolites and lipids are the goal of highly advanced omics technologies such as proteomics, transcriptomics, genomics, metabolomics and lipidomics. Recently, the number of studies using omics approaches to profile the FFPE tissues has markedly increased. However, the application of omics technologies remains challenging mainly due to the harsh fixation and embedding process that severely impacts the integrity and quality of biomolecules [3]. Considerable efforts have been made to develop the optimized and standardized protocols for extraction and separation of protein, DNA and RNA from FFPE samples by testing different factors such as buffer components, detergents, pH, temperature, pressure and others [8; 9; 10; 11]. These methods aim to optimise reproducible, cost-effective and efficient protocols that are compatible with omics techniques. Analytical protocols for the profiling of FFPE samples have been also established, optimized and used in radiation biology studies [12; 13; 14]. In this review, we describe the characteristics of radiobiological archives with available FFPE samples and the recent advances in omics analysis on FFPE tissues in radiation research. The main problems and challenges to be overcome for the optimal application of omics on radiobiological FFPE samples are further discussed.