Fig. 1

Disease progression and aberrant gene methylation in the two patients with multiple extramedullary diseases. a Disease course of patient 1 depicted by the response of immunoglobin (Ig) G and timing of tissue/bone marrow (BM) sampling. b Upper endoscopy of patient 1 showed polypoid lesion in duodenum (arrowed). c PET-CT of patient 1 showed multiple hypermetabolic extramedullary plasmacytomas (EMP) in the right anterior third rib, mediastinal and mid-jejunum causing intussusception (arrowed). d Histology of biopsy of chest wall mass of patient 1 showing exclusively infiltration with pleomorphic hyperchromatic plasma cells (H&E stain, original magnification 400×). e Disease course of patient 2 depicted by the response of free kappa light chain. f Methylation-specific polymerase chain reaction (MSP) study of SHP1, CDKN2A, CDH1, CD56, and CXCR4. L: DNA Ladder; B: bank; N1 and N2: normal marrow DNA; S1–4: diagnostic BM, duodenal plasmacytoma, chest wall plasmacytoma, paired BM of patient 1; S5–8: diagnostic BM, extradural plasmacytoma, paired BM and peripheral blood at secondary plasma cell leukemia (sPCL) of patient 2; PC: positive control of methylated DNA. In patient 1, SHP1 and CDKN2A were methylated at two EMPs and the paired bone marrow. Methylation of E-CAD was detected only in the chest wall plasmacytoma. In patient 2, methylation of SHP1 occurred in extradural plasmacytoma (2 months after diagnosis) and peripheral blood at the time of sPCL. DNA integrity was demonstrated by positive amplification of unmethylated-MSP of SHP1. g Pyrosequencing analysis of SHP1 in the chest wall plasmacytoma of patient 1 showing a mean CpG methylation of 23%. Abbreviations: VCD: bortezomib, cyclophosphamide and dexamethasone; pem-VRD: pembrolizumab-bortezomib-lenalidomide-dexamethason; Dara-KPD: daratumumab, carfilzomib, pomalidomide, dexamethasone; VTD: bortezomib, thalidomide, dexamethasone; ASCT: autologous stem cell transplantation. _*: methylated MSP products were all verified by Sanger sequencing. Sequences are shown in Additional file 1: Figure S2