Dickkopf-related protein 1 expression in bone marrow of multiple myeloma patients: correlation with bone disease and plasma cell malignancy type.

BACKGROUND: Previous studies have pointed out the role of dickkopf-related protein 1 (DKK 1) - Wnt inhibitor, which is essential for osteoblast functioning, in the development of osteolytic lesions in multiple myeloma (MM). AIM: To assess the DKK 1 expression displayed by myeloma cells in bone marrow trephine biopsies of patients with and without osteolytic lesions, and in different malignancy grades of the disease. METHODS: The expression level of DKK 1 was assessed immunohistochemically in bone marrow of 49 MM patients presented with and without osteolytic lesions (the 1st and the 2nd group, respectively). RESULTS: Levels of weak, moderate, and strong DKK 1 expression were distributed - as 43.33, 27.78 and 25.56%, and 63.91, 18.80, and 1.50%, respectively when evaluating the samples obtained from the 1st and the 2nd group. Statistically significant differences were found when the levels of DKK 1 expression in the 1st and the 2nd group were compared (χ2 = 51; df = 3; p < 0.001). CONCLUSIONS: DKK 1 contributes to the development of osteolytic lesions in MM. The present study provides morphological evidence that inhibition in Wnt signaling may lead to bone damage observed in the advanced stage of the disease.

A successful case of venetoclax-based therapy in relapsed/refractory secondary plasma cell leukemia.

BACKGROUND: Secondary plasma cell leukemia (sPCL) patients typically are either refractory to conventional therapies or have short remissions to drug regimens used in multiple myeloma (MM), which highlights sPCL's aggressive nature and association with advanced stage disease. t(11,14) is correlated with increased BCL-2 expression, which makes it a cytogenic marker of interest for use of the BCL-2 inhibitor venetoclax. Little data of venetoclax's use has been published in plasma cell leukemia. We present a case of a refractory/relapsed sPCL patient displaying t(11,14) who achieved a very good partial response (VGPR) from venetoclax therapy in combination with dexamethasone and bortezomib. CASE REPORT: Our case describes a 67-year-old male initially diagnosed with IgG kappa MM in 2013, which transformed into non-secretory secondary plasma cell leukemia. Over a two-year period, despite responses to various therapies, the patient continued to experience relapses and exhausted options of novel agents seen in MM treatment. The patient was started on venetoclax in combination with bortezomib and oral dexamethasone. MANAGEMENT AND OUTCOME: Due to the patient's disease transformation into a non-secretory form of sPCL, PET/CT scans were relied upon to monitor disease progression. The PET/CT scan after three months of venetoclax combination treatment showed a very good partial response to therapy, with near resolution of metabolically active osseous disease. DISCUSSION: The success of venetoclax-based therapy in achieving a very good partial response suggests its utility in relapsed/refractory sPCL patients, who have exhausted various combinations of drug regimens used in treatment of MM and have historically poor survival outcomes.

Global methylation patterns in primary plasma cell leukemia.

Primary plasma cell leukemia (pPCL) is a rare and very aggressive variant of multiple myeloma (MM). Specific clinical, biological and molecular patterns distinguish pPCL from MM. Here, we performed a genome-wide methylation analysis by high-density array in 14 newly diagnosed pPCL patients along with 60 MMs, and 5 patients affected by monoclonal gammopathy of uncertain significance (MGUS). Our analysis revealed a global hypomethylation profile associated with pPCL. Additionally, differential methylation patterns were found related to distinct chromosomal aberrations and DIS3 mutations, affecting genes with roles in bone metabolism, cell migration, transcription regulation or DNA damage response. When compared with MM patients, pPCL showed a distinct methylation profile mostly characterized by hypomethylated probes specific for genes involved in several processes like cell adhesion and migration. Furthermore, decreasing methylation levels were evidenced for genes significantly modulated in the progressive phases of plasma cell dyscrasias, from MGUS to MM and pPCL. Overall, our data provide new insights into the molecular characterization of pPCL, thus being potentially useful in the prognostic stratification or identification of novel molecular targets.

Blastic plasmacytoid dendritic cell neoplasm: a rare case of gingival lesion with leukaemic presentation.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare haematological malignancy with an aggressive clinical course. It has been recognised as a distinct entity in the WHO 2008 classification of haematolymphoid neoplasm. This disease usually presents with cutaneous involvement as the first manifestation, with subsequent or simultaneous spread to bone marrow and peripheral blood with leukaemic dissemination. Gingival lesion as the first manifestation, in the absence of a cutaneous lesion, is an uncommon presentation of this rare disease. We report a case of an elderly woman, aged 84 years, who presented with a lump on the mandibular gingiva and ipsilateral otalgia without any cutaneous lesion and associated with an highly aggressive and rapid leukaemia. This case is an addition to the handful of those cases of BPDCN which presents without cutaneous involvement, but it is exceedingly rare for clinical features that make it a unique case in the literature.

Plasma cell leukemia: update on biology and therapy.

Plasma cell leukemia (PCL) is a rare, but very aggressive, plasma cell dyscrasia, representing a distinct clinicopathological entity as compared to multiple myeloma (MM), with peculiar biological and clinical features. A hundred times rarer than MM, the disease course is characterized by short remissions and poor survival. PCL is defined by an increased percentage (>20%) and absolute number (>2 × 109/l) of plasma cells in the peripheral blood. PCL is defined as 'primary' when peripheral plasmacytosis is detected at diagnosis, 'secondary' when leukemization occurs in a patient with preexisting MM. Novel agents have revolutionized the outcomes of MM patients and have been introduced also for the treatment of PCL. Here, we provide an update on biology and treatment options for PCL.

Proteome alterations associated with transformation of multiple myeloma to secondary plasma cell leukemia.

Plasma cell leukemia is a rare and aggressive plasma cell neoplasm that may either originate de novo (primary PCL) or by leukemic transformation of multiple myeloma (MM) to secondary PCL (sPCL). The prognosis of sPCL is very poor, and currently no standard treatment is available due to lack of prospective clinical studies. In an attempt to elucidate factors contributing to transformation, we have performed super-SILAC quantitative proteome profiling of malignant plasma cells collected from the same patient at both the MM and sPCL stages of the disease. 795 proteins were found to be differentially expressed in the MM and sPCL samples. Gene ontology analysis indicated a metabolic shift towards aerobic glycolysis in sPCL as well as marked down-regulation of enzymes involved in glycan synthesis, potentially mediating altered glycosylation of surface receptors. There was no significant change in overall genomic 5-methylcytosine or 5-hydroxymethylcytosine at the two stages, indicating that epigenetic dysregulation was not a major driver of transformation to sPCL. The present study constitutes the first attempt to provide a comprehensive map of the altered protein expression profile accompanying transformation of MM to sPCL in a single patient, identifying several candidate proteins that can be targeted by currently available small molecule drugs. Our dataset furthermore constitutes a reference dataset for further proteomic analysis of sPCL transformation.

Notch signaling deregulation in multiple myeloma: A rational molecular target.

Despite recent therapeutic advances, multiple myeloma (MM) is still an incurable neoplasia due to intrinsic or acquired resistance to therapy. Myeloma cell localization in the bone marrow milieu allows direct interactions between tumor cells and non-tumor bone marrow cells which promote neoplastic cell growth, survival, bone disease, acquisition of drug resistance and consequent relapse. Twenty percent of MM patients are at high-risk of treatment failure as defined by tumor markers or presentation as plasma cell leukemia. Cumulative evidences indicate a key role of Notch signaling in multiple myeloma onset and progression. Unlike other Notch-related malignancies, where the majority of patients carry gain-of-function mutations in Notch pathway members, in MM cell Notch signaling is aberrantly activated due to an increased expression of Notch receptors and ligands; notably, this also results in the activation of Notch signaling in surrounding stromal cells which contributes to myeloma cell proliferation, survival and migration, as well as to bone disease and intrinsic and acquired pharmacological resistance. Here we review the last findings on the mechanisms and the effects of Notch signaling dysregulation in MM and provide a rationale for a therapeutic strategy aiming at inhibiting Notch signaling, along with a complete overview on the currently available Notch-directed approaches.

Characterization of a new human plasma cell leukemia cell line UHKT-944.

OBJECTIVE: A new interleukin-6 (IL-6)-dependent plasma cell leukemia cell line UHKT-944 was established from bone marrow cells derived from a 55-yr-old man with plasma cell leukemia. RESULTS: The cell line possesses phenotypic characteristics of plasma cells including the production of a monoclonal immunoglobulin IgA1-kappa. VH3-9 region of IgVH genes was rearranged and somatically hypermutated. The UHKT-944 cells were found to be negative for most of tested B-cell, T-cell, and myeloid markers. According to cytogenetic analysis, the cells were classified as near tetraploid with several numerical and structural abnormalities including the t(14;20) involving IgH locus. CONCLUSION: The established permanent plasma cell leukemia cell line is a suitable model for the study of cellular and molecular mechanisms of pathogenesis of this rare malignant disease.

A case of CD138-/CD19+/CD4+ IgD plasma cell leukemia.

BACKGROUND: Plasma cell leukemia (PCL) is an uncommon and aggressive disease caused by the clonal proliferation of atypical plasma cells with phenotypical abnormalities similar to those seen in multiple myeloma (MM), although at different rates. Here, we report a case of IgD PCL with a very unusual CD138-/CD19+/CD4+ phenotype. METHODS: Peripheral blood and bone marrow samples from a 37-year-old patient afflicted by an aggressive plasma cell dyscrasia were examined and analyzed by conventional morphology, flow cytometry, and immunohistochemistry. RESULTS: Analysis of peripheral blood fulfilled criteria for PCL (more than 20% and more than 2 × 10e9 cells/L). However, flow cytometry and immunohistochemistry phenotyping revealed that the cells were CD138-/CD38+/CD19+/CD4+/CD56-/CD117-. CONCLUSIONS: PCL is diagnosed on peripheral blood smear. Immunophenotyping is a tool that can be helpful in diagnosing difficult cases but its atypical findings should not prevent the appropriate PCL diagnosis in clinically and morphologically unquestionable cases. © 2014 International Clinical Cytometry Society.

Nestin expression throughout multistep pathogenesis of multiple myeloma.

The stem cell marker nestin (NES) is found in dividing cells of developing and regenerating tissues. Upon terminal differentiation, NES expression is diminished but may be re-expressed following injury or in cancer. Surprisingly, we recently confirmed NES as a tumour-specific marker for mature CD138(+) 38(+) plasma cells (PC) in multiple myeloma (MM). The present study analysed NES expression throughout the spectrum of MM developmental stages, starting with individuals with no haematological malignancy, through monoclonal gammopathy of undetermined significance (MGUS) and MM to plasma cell leukaemia (PCL) and MM cell lines. NES was analysed in bone marrow PC of 163 MM, four PCL and nine MGUS patients, 10 individuals with no haematological malignancy and 6 myeloma cell lines (OPM-2, RPMI-8226, MOLP-8, U-266, EJM, NCI-H929) by flow cytometry and/or real-time polymerase chain reaction or immunochemistry. We observed a tendency of increased NES expression in parallel with disease progression. NES was evaluated as a reliable marker for accurate discrimination between MM patients and the control group. High NES levels were strongly associated with the presence of 1q21 gain. For the first time, NES was demonstrated to predict worse response to conventional therapy/novel agents. These results suggest that NES might become a useful clinical parameter with an important role in MM pathogenesis.

Biclonal light chain gammopathy with aberrant CD33 expression in secondary plasma cell leukemia.

Plasma cell leukemia is a rare neoplastic proliferation of circulating plasma cells. Clonal proliferations of plasma cells, such as in plasma cell leukemia or plasma cell myeloma, are typically characterized by production of a monoclonal heavy and/or light chain immunoglobulin. We present a case of a secondary plasma cell leukemia arising from plasma cell myeloma with dual expression of lambda and kappa light chains along with aberrant expression of CD33, CD20, and dim CD56. This case emphasizes the importance of recognizing aberrant immunophenotypes in plasma cell leukemias and represents the first reported case of biclonal light chain expression in a secondary plasma cell leukemia.