Dormant myeloma cells express a myeloid transcriptome signature. scRNAseq analysis of eGFP⁺DiD^hi dormant and eGFP⁺DiD^neg reactivated cell populations using MARS-seq. (A) t-distributed stochastic neighbor embedding (t-SNE) plots of the MARS-seq analysis of 1067 single myeloma cells identifies 3 distinct clusters (0, 1, and 2) (top) and maps eGFP⁺DiD^hi dormant cells to cluster 2 (gold; D) and eGFP⁺DiD^neg reactivated cells to C0 and C1 (gray, R) (bottom). (B) Heatmap of the top 20 genes contributing to each cluster (red, 0; green, 1; and blue, 2). (C) Database for Annotation, Visualization and Integrated Discovery functional annotation of the top 5 biological processes associated with each cluster. (D) Transcript profile of 10 common genes identified by MARS-seq (top) and SMART-seq (bottom) workflows for individual dormant (gold) and reactivated (gray) cells. Horizontal lines are the median; box indicates the IQR. (E) Histograms of expression of myeloid markers (top) and quantitation of mean fluorescent intensity of expression (MFI; bottom) of Gr1⁺CD11b⁺ bone marrow (BM), eGFP⁺DiD^hi dormant, and eGFP⁺DiD^neg reactivated cells. Mann-Whitney test: ***P < .001. UMI, unique molecular identifier.