BCR and B-cell chronic lymphocytic leukemia: Based on the high consistency of SNVs, SMGs, and CNVs, the different BCR IGH rearrangement features in LN and BM, and the different light chain expression in CLL and MM cells, we concluded that CLL and MM cells originated from the same hematopoietic stem cell/progenitors, different pro-B cells, and suffered oncogenic mutations at different B cell differentiation stages.