Single-cell mRNA sequencing confirm heterogeneity at the transcriptional level. (A) Heat maps showing the single-cell mRNA expression of malignant cells from 6 patients with SS. (B) Single-cell mRNA coexpression of CCR7, CXCR4, IL7R, LGALS1, PSMB4, PTPRC, S100A10, S100A4, and SELL within the malignant population of 6 patients with SS visualized by t-SNE plots. Color indicate the log2 transformed number of unique molecular identifier (UMI) counts for each gene from the individual cells.