IGHG4 and plasma cell myeloma: The four identified cell subgroups were as follows: C0 IGLL5+ Myeloma Cells (724 cells), C1 IGHG4+ Myeloma Cells (310 cells), C2 MALAT1+ Myeloma Cells (305 cells), and C3 IGHG1+ Myeloma Cells (149 cells).