Mass Spectrometry Quantification of Epigenetic Changes: A Scoping Review for Cancer and Beyond.

Mass spectrometry has become an indispensable tool for the identification and quantification of epigenetic modifications, offering both high sensitivity and structural specificity. The two major classes of epigenetic modifications identified-DNA methylation and histone post-translational modifications-play fundamental roles in cancer development, underscoring the relevance of their precise quantification for understanding tumorigenesis and potential therapeutic targeting. In this scoping review, we included 89 studies that met the inclusion criteria for detailed methodological assessment. Among these, we compared pre-treatment workflows, analytical platforms, and acquisition modes employed to characterize epigenetic modifications in human samples and model systems. Our synthesis highlights the predominance of bottom-up strategies combined with Orbitrap-based platforms and data-dependent acquisition for histone post-translational modifications, whereas triple quadrupole mass spectrometers were predominant for DNA methylation quantification. We critically evaluate current limitations, including heterogeneity in validation reporting, insufficient coverage of combinatorial post-translational modifications, and variability in derivatization efficiency.