Abstract This Fast Track proposal's overarching goal is to develop a comprehensive platform for the identification and validation of recombinant antibodies (Abs) that are specific to protein isoform splice-junction sites. This initiative addresses key challenges in the protein-level characterization of splice variants, which is a critical area in understanding and treating diseases related to alternative splicing of proteins. The project introduces an innovative "Epivolve" phage display technology, utilizing a “pseudo-haptenylated” amino acid to generate site-directed Abs against these splice variants. The initial phase of the project, Phase I, will focus on validating the several existing splice- site specific Abs through methods such as western blotting and flow cytometry, with a vision to expand applications in future offerings. And the use of Epivolve to generate Abs de novo from phage display libraries to the same sites as a proof of concept. This strategy is significant as alternative splicing is known to contribute to the malignant progression of cancer, highlighting the potential impact of this research in oncology. Phase II of the proposal takes the project further by producing display libraries in a novel vector system that combines phage- and yeast display technologies. A key aspect of this phase is the targeted effort to identify potential neoantigens near the amino terminus of G-protein-coupled receptors, a potentially promising area in cancer research. Additionally, the proposal outlines a commercialization strategy, reflecting the project's progression towards practical applications. The final step in this strategy involves scaling up the production of these site-directed Abs and continuing their validation. This phase is crucial to ensure the effectiveness and reliability of the Abs for broader use, potentially revolutionizing the approach to diagnosing and treating diseases related to protein splicing.