Mass spectrometry-based proteomic approaches for postmortem interval estimation: A systematic review

Accurate postmortem interval (PMI) estimation remains a major challenge in forensic science due to the influence of biological, environmental, and circumstantial factors on traditional methods. Mass spectrometry-based proteomics has emerged as a promising approach by enabling the analysis of time-dependent postmortem protein degradation. This systematic review (2020-2025) aims to synthesize recent advances in MS-based proteomic techniques for PMI estimation, identify reproducible protein biomarkers, and evaluate their forensic applicability.

A systematic literature search was conducted in PubMed, Scopus, and ScienceDirect for studies published between January 2020 and August 2025, following PRISMA guidelines. Search terms included "postmortem interval," "time since death," "protein degradation," "forensic proteomics," and "mass spectrometry." Original research studies using human or animal tissues and MS-based proteomic methods for PMI estimation were included. Reviews, non-English publications, and duplicates were excluded. Study selection and data extraction were performed independently by two reviewers.

Twenty-one studies met the inclusion criteria: ten on human samples, ten on animal models, and one on combined datasets. Skeletal muscle was the most frequently analyzed tissue, followed by bone, liver, heart, and gingiva. Several proteins, including tropomyosin, GAPDH, desmin, tubulin, and eEF1A2, demonstrated reproducible, time-dependent degradation patterns. Analytical approaches such as GC-MS, LC-MS/MS, and MALDI-MS enabled sensitive detection of postmortem proteomic changes. However, substantial variability was observed across studies in tissue selection, postmortem conditions, and analytical protocols, highlighting the need for standardization.

Mass spectrometry-based proteomics offers a sensitive and objective approach for PMI estimation and identifies several candidate protein biomarkers with potential forensic utility. Broader application requires standardized protocols, larger validation studies in human samples, and the development of multi-protein marker panels. With further refinement, proteomic profiling could serve as a robust complement to conventional PMI estimation methods in routine forensic practice.