Contributions
Abstract: PB2175
Type: Publication Only
Background
the study of the immunophenotype of tumor plasma cells of the bone marrow (PC BM) and circulating tumor cells (CTC MM) can reveal new mechanisms of metastasis and generalization of the disease in multiple myeloma (MM) complicated by plasmacytomas.
Aims
the study of the immunophenotypic profile of bone marrow tumor cells and circulating tumor cells in patients with multiple myeloma complicated by plasmacytomas, depending on the clinical course of the disease.
Methods
18 patients with MM (9 women, 9 men), from 41 to 85 years (median 59 years) were examined. All patients had 3 stages of the disease according to Salmon-Durie, and plasmacytomas of different localization. The average level of plasma cells in CM according to the myelogram is 19.3% (0.4-69.0%). The first detected MM was in 9 patients, 9 previously received therapy (VCP, VMP, RVP). In 13 (72.2%) patients there were bone plasmocytomas, in 5 (27.8%) - extramedullary plasmacytomas. In 14 (77.8%) patients, the plasmacytomas were more than 7 cm in diameter (bulky disease). Differences between PC KM and COCMM in patients with primary and pre-treated, with solitary bone and extramedullary plasmacytomas, in patients with plasmacytomas more than 7 cm were assessed.
Results
in primary and treated patients a significantly higher level of CD138 + on PC KM is determined in comparison with COC MM. In both groups, the detectability of CD138 cells was significantly higher at CIC MM. There was no significant difference in the detection of CD56, CD11c, CD117, CD81, CD33, CD27, CD28, CD19, CD20, CD79b in both groups. Patients with bone plasmacytomas have a higher detectability of CD138 + on PC KM compared to COCMM. Detectability of CD138- was higher at COC MM. In the group of patients with extramedullary plasmacytomas, there was no significant difference in the detection of CD138 + and CD138-between CM of PC and COC of MM, there were no other antigens. When comparing the detectability of plasmocyte antigens versus the size of the plasmacytoma - more than 7 and less than 7 cm in both groups, a significant predominance of CD138 + cells in the CM KM and a higher detection of CD138 cells at COC MM were revealed.
Conclusion
immunophenotypically CTCs of MM are less mature cells compared to PC KM, losing the antigen CD138 + and the connection with the bone marrow stroma. These results were noted in both primary and treated patients, as well as when comparing patients with plasmacytomas more than 7 cm and less than 7 cm. In this connection, the loss of surface CD138 + by the plasma cell can be regarded as one of the mechanisms of metastasis and progression of MM. In the group of extramedullary plasmocytes, there were no significant differences between PC BM and CTC MM, which allows us to conclude that the immunophenotypic identity of these cells is medullar. However, these data require further study due to the small sample of patients in this group.
Session topic: 14. Myeloma and other monoclonal gammopathies - Clinical
Abstract: PB2175
Type: Publication Only
Background
the study of the immunophenotype of tumor plasma cells of the bone marrow (PC BM) and circulating tumor cells (CTC MM) can reveal new mechanisms of metastasis and generalization of the disease in multiple myeloma (MM) complicated by plasmacytomas.
Aims
the study of the immunophenotypic profile of bone marrow tumor cells and circulating tumor cells in patients with multiple myeloma complicated by plasmacytomas, depending on the clinical course of the disease.
Methods
18 patients with MM (9 women, 9 men), from 41 to 85 years (median 59 years) were examined. All patients had 3 stages of the disease according to Salmon-Durie, and plasmacytomas of different localization. The average level of plasma cells in CM according to the myelogram is 19.3% (0.4-69.0%). The first detected MM was in 9 patients, 9 previously received therapy (VCP, VMP, RVP). In 13 (72.2%) patients there were bone plasmocytomas, in 5 (27.8%) - extramedullary plasmacytomas. In 14 (77.8%) patients, the plasmacytomas were more than 7 cm in diameter (bulky disease). Differences between PC KM and COCMM in patients with primary and pre-treated, with solitary bone and extramedullary plasmacytomas, in patients with plasmacytomas more than 7 cm were assessed.
Results
in primary and treated patients a significantly higher level of CD138 + on PC KM is determined in comparison with COC MM. In both groups, the detectability of CD138 cells was significantly higher at CIC MM. There was no significant difference in the detection of CD56, CD11c, CD117, CD81, CD33, CD27, CD28, CD19, CD20, CD79b in both groups. Patients with bone plasmacytomas have a higher detectability of CD138 + on PC KM compared to COCMM. Detectability of CD138- was higher at COC MM. In the group of patients with extramedullary plasmacytomas, there was no significant difference in the detection of CD138 + and CD138-between CM of PC and COC of MM, there were no other antigens. When comparing the detectability of plasmocyte antigens versus the size of the plasmacytoma - more than 7 and less than 7 cm in both groups, a significant predominance of CD138 + cells in the CM KM and a higher detection of CD138 cells at COC MM were revealed.
Conclusion
immunophenotypically CTCs of MM are less mature cells compared to PC KM, losing the antigen CD138 + and the connection with the bone marrow stroma. These results were noted in both primary and treated patients, as well as when comparing patients with plasmacytomas more than 7 cm and less than 7 cm. In this connection, the loss of surface CD138 + by the plasma cell can be regarded as one of the mechanisms of metastasis and progression of MM. In the group of extramedullary plasmocytes, there were no significant differences between PC BM and CTC MM, which allows us to conclude that the immunophenotypic identity of these cells is medullar. However, these data require further study due to the small sample of patients in this group.
Session topic: 14. Myeloma and other monoclonal gammopathies - Clinical