Current gene testing reveals only the mutation status yet lacks protein expression of the actual drug target. A comprehensive evaluation requires methods that integrate the absolute quantification of mutant proteins with global profiling of downstream signaling and resistance pathways. Here, we present an isotope pair-separated data-independent acquisition (IsoPS-DIA) strategy with a dual functionality of multiplexed absolute quantification and global proteome profiling in a single run. IsoPS-DIA features a dual-window design: narrow consecutive windows separate light/heavy-isotope-labeled peptide pairs to reduce coisolation interference and maximize usable fragment ions, while wide variable windows capture proteome-wide information.
