SDC1 and neoplasm: Concurrent single‐cell sequencing of tumour clonotypes with rearrangement of variable‐diversity‐joining regions and transcriptomes (scVDJ‐ and scRNA‐seq) was used to analyse BM CD138+ cells from 18 MM patients, including 12 NDMM subjects and 6 RRMM subjects, and an overview of experimental design is shown in Figure 1A.