Updated project metadata. Prostate cancer (PCa) has a significant ability to disseminate and survive in the bone marrow (BM). Once there, disseminated tumor cells (DTCs) may lie dormant for years, but often eventually reactivate proliferative pathways, thus largely contributing to bone metastasis, disease progression, and relapse. Unfortunately, quiescent PCa cells are difficult to identify and target with treatment, in part because formerly identified relevant markers are intracellular and regulated by protein stability. We sought to address this problem by identifying a G0 marker that is expressed on the cell surface and therefore amenable to antibody binding for identification and therapeutic targeting. In doing so, we utilized stably transduced fluorescent markers for CDKN1B (p27) and CDT1 protein levels, which separate viable PCa cells into G0, G1, or combined S/G2/M populations (as described in PMID 34957090). We then performed FACS to collect G1 and G0 PC3 PCa cells, isolated membrane proteins, and subsequently used GC-MS proteomics to determine differences in protein abundance between G0 and G1. In total, 3,791 proteins were identified.