Contributions
Abstract: PB2146
Type: Publication Only
Background
The common feature shared by primary plasma cell leukemia (pPCL) and multiple myeloma (MM) with circulating plasma cells (CPCs) is the expansion of plasma cells independent of bone marrow (BM). The presence of CPCs is considered as a marker of highly proliferative disease and an adverse independent prognostic factor. The diagnosis of pPCL is based upon absolute number (≥ 2 x 109/L) and/or the percentage (≥ 20 %) of CPCs in peripheral blood (PB).
Cytogenetic studies showed that CPCs have a variety of genetic abnormalities. Majority of cytogenetic abnormalities in patients with CPCs are non-hyperdiploid with higher frequency of major IgH translocations, i.e. t(11;14)(q13;q32), t(4;14)(p16;q32) and t(14;16)(q32;q23). The most common abnormalities are deletion of 13q/ monosomy 13, deletion of 17p and abnormalities of chromosome 1 (1q21 gain/ deletion 1p21).
Aims
The aims of the present study were to analyze cytogenetic changes in a cohort of 7 patients (3 with pPCL and 4 MM with CPCs).
Methods
We used array comparative genomic hybdridization (arrayCGH) and FICTION method (fluorescence immunophenotyping and interphase fluorescence in situ hybridization) with commercially available probes specific for RB1/c15, IgH, 1q21/1p32, TP53/c17, to assess clonal evolution in BM and CPCs and to evaluate the prognostic importance.
Results
We detected translocation of IgH gene in 4 out of 7 patients- t(11;14) in 3 patients, t(4;14) in one patient. In one patient we delineated der(4)t(4;7)(p16;q?)ins(4;7)(p16;q?) including FGFR3/MMSET. Gain of 1q21 was found in 5/7 patients. Deletion of RB1 gene was detected only in 2/7 patients and TP53 deletion in one patient. Abnormalities identified in BM were also found in CPCs.
ArrayCGH found common deletions of 1p, 6q, 13q, 16q and gain of 1q, chromosome X abnormalities (monosomy/Xq gain). Chromotripsis of chromosome 8 and hyperdiploidy with trisomies of chromosomes 3, 5, 7, 9, 11, 15 and 19 was found in 2 other patients.
Conclusion
In summary, genetic aberrations were recorded in all 7 analyzed cases with PCL and MM with CPCs. We found numerical changes as well as structural aberrations similarly as in MM patients. Our findings underline that genetic abnormalities are more frequent in PCL/MM with CPCs than in MM patients and they tend to be more complex.
This work was supported by grant IGA_LF_2018_004.
Session topic: 13. Myeloma and other monoclonal gammopathies – Biology & Translational Research
Keyword(s): Cytogenetic abnormalities, Myeloma, Plasma cells
Abstract: PB2146
Type: Publication Only
Background
The common feature shared by primary plasma cell leukemia (pPCL) and multiple myeloma (MM) with circulating plasma cells (CPCs) is the expansion of plasma cells independent of bone marrow (BM). The presence of CPCs is considered as a marker of highly proliferative disease and an adverse independent prognostic factor. The diagnosis of pPCL is based upon absolute number (≥ 2 x 109/L) and/or the percentage (≥ 20 %) of CPCs in peripheral blood (PB).
Cytogenetic studies showed that CPCs have a variety of genetic abnormalities. Majority of cytogenetic abnormalities in patients with CPCs are non-hyperdiploid with higher frequency of major IgH translocations, i.e. t(11;14)(q13;q32), t(4;14)(p16;q32) and t(14;16)(q32;q23). The most common abnormalities are deletion of 13q/ monosomy 13, deletion of 17p and abnormalities of chromosome 1 (1q21 gain/ deletion 1p21).
Aims
The aims of the present study were to analyze cytogenetic changes in a cohort of 7 patients (3 with pPCL and 4 MM with CPCs).
Methods
We used array comparative genomic hybdridization (arrayCGH) and FICTION method (fluorescence immunophenotyping and interphase fluorescence in situ hybridization) with commercially available probes specific for RB1/c15, IgH, 1q21/1p32, TP53/c17, to assess clonal evolution in BM and CPCs and to evaluate the prognostic importance.
Results
We detected translocation of IgH gene in 4 out of 7 patients- t(11;14) in 3 patients, t(4;14) in one patient. In one patient we delineated der(4)t(4;7)(p16;q?)ins(4;7)(p16;q?) including FGFR3/MMSET. Gain of 1q21 was found in 5/7 patients. Deletion of RB1 gene was detected only in 2/7 patients and TP53 deletion in one patient. Abnormalities identified in BM were also found in CPCs.
ArrayCGH found common deletions of 1p, 6q, 13q, 16q and gain of 1q, chromosome X abnormalities (monosomy/Xq gain). Chromotripsis of chromosome 8 and hyperdiploidy with trisomies of chromosomes 3, 5, 7, 9, 11, 15 and 19 was found in 2 other patients.
Conclusion
In summary, genetic aberrations were recorded in all 7 analyzed cases with PCL and MM with CPCs. We found numerical changes as well as structural aberrations similarly as in MM patients. Our findings underline that genetic abnormalities are more frequent in PCL/MM with CPCs than in MM patients and they tend to be more complex.
This work was supported by grant IGA_LF_2018_004.
Session topic: 13. Myeloma and other monoclonal gammopathies – Biology & Translational Research
Keyword(s): Cytogenetic abnormalities, Myeloma, Plasma cells