applied sciences Review Proteomics in Forensic Analysis: Applications for Human Samples Van-An Duong 1,† , Jong-Moon Park 1,† , Hee-Joung Lim 2, * and Hookeun Lee 1, *   Citation: Duong, V.-A.; Park, J.-M.; Lim, H.-J.; Lee, H. Proteomics in Forensic Analysis: Applications for Human Samples. Appl. Sci. 2021, 11, 3393. https://doi.org/10.3390/app 11083393 Academic Editor: Claudio Medana Received: 11 March 2021 Accepted: 6 April 2021 Published: 9 April 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 College of Pharmacy, Gachon University, Incheon 21936, Korea; anduong@gachon.ac.kr (V.-A.D.); bio4647@naver.com (J.-M.P.) 2 Forensic Science Center for Odor Fingerprint Analysis, Police Science Institute, Korean National Police University, Asan 31539, Korea * Correspondence: limhj@police.go.kr (H.-J.L.); hklee@gachon.ac.kr (H.L.); Tel.: +82-41-968-2893 (H.-J.L.); +82-32-820-4927 (H.L.) † These authors contributed equally. Abstract: Proteomics, the large-scale study of all proteins of an organism or system, is a powerful tool for studying biological systems. It can provide a holistic view of the physiological and biochemical states of given samples through identification and quantification of large numbers of peptides and proteins. In forensic science, proteomics can be used as a confirmatory and orthogonal technique for well-built genomic analyses. Proteomics is highly valuable in cases where nucleic acids are absent or degraded, such as hair and bone samples. It can be used to identify body fluids, ethnic group, gender, individual, and estimate post-mortem interval using bone, muscle, and decomposition fluid samples. Compared to genomic analysis, proteomics can provide a better global picture of a sample. It has been used in forensic science for a wide range of sample types and applications. In this review, we briefly introduce proteomic methods, including sample preparation techniques, data acquisition using liquid chromatography-tandem mass spectrometry, and data analysis using database search, spectral library search, and de novo sequencing. We also summarize recent applications in the past decade of proteomics in forensic science with a special focus on human samples, including hair, bone, body fluids, fingernail, muscle, brain, and fingermark, and address the challenges, considerations, and future developments of forensic proteomics. Keywords: forensics; proteomics; biomarker; human identification; serology; hair; bone 1. Introduction Proteomics is the study of proteomes (i.e., the total proteins of a given sample such as cultured cells, a tissue, or an organism) and their changes in response to environmen- tal or physiological conditions [1]. Proteomics identifies proteome profiles of samples, thereby revealing the biological status of the samples as well as their regulatory or disease mechanisms. Proteomics has been widely used to study microbiology, cell and molecular biology, plant sciences, marine sciences, food sciences, cancer, and immunology [2]. The development of proteomics relies on a number of technologies and techniques, includ- ing liquid chromatography-tandem mass spectrometry (LC-MS/MS) and statistical and bioinformatics tools [3]. Proteomics is a powerful approach for studying biological systems. Recent develop- ments in LC-MS/MS have allowed rapid analyses of peptides and proteins in samples, which is comparable to next-generation sequencing (NGS). Compared with immunologi- cal methods that require antibodies and polymerase chain reaction (PCR) using specific primers, proteomics may reduce time and overall analysis costs. It does not depend on the development of new antibodies or primers for specific proteins [4]. Proteomics enables the identification and quantification of various peptides and proteins in a single experiment with high specificity. Thus, it not only measures a large number of targets, but also provides Appl. Sci. 2021, 11, 3393. https://doi.org/10.3390/app11083393 https://www.mdpi.com/journal/applsci