Monitoring of the Clonal Fraction by Fluorescence In Situ Hybridization in Myelodysplastic Syndrome: Comparison With International Working Group Treatment Response Criteria

Genetic profile of primary plasma cell leukemia in Korea: comparison with plasma cell myeloma

Plasma cell leukemia (PCL) is clinically and genetically distinct from multiple myeloma (MM), despite controversies regarding the disease definition. To determine the distinct features of PCL, the genetic property of primary PCL (pPCL) was compared with that of secondary PCL (sPCL) and MM. In patients with pPCL, Eighty-nine non-synonymous mutations were observed in 68 genes. The most frequently mutated genes were TP53, TSC2, and TYK2. In comparison with genetic abnormalities of sPCL and MM, 45 genes were present only in pPCL while 28 genes were only in sPCL and 22 genes only in MM. Among the common genes between pPCL and MM, a higher prevalence of TP53 was observed in pPCL, compared to MM (p < 0.05), while similar, compared to sPCL (p = 0.64). In summary, pPCL patients showed a higher level of genetic heterogeneity and distinctive genetic signature in their mutational profile compared to patients with MM and sPCL.

Targeted sequencing aids in identifying clonality in chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) typically shows monocytosis in the peripheral blood (PB), which must be differentiated from reactive monocytosis. To determine the clonality of CMML, we performed molecular and cytogenetic analysis in Korean patients. To investigate whether monocytes in the PB harbored clonal mutational changes, we performed single-cell sequencing after selecting monocytes, neutrophils, and lymphocytes by morphology-aided laser microdissection. Targeted sequencing was performed in 35 patients with CMML with 41 bone marrow samples. Single-cell analysis was performed in two cases. Most (94.3%) patients harbored at least one variant, in genes considered as potential therapeutic targets, while cytogenetic aberrations occurred in only 28.6% of cases. ASXL1 (54.3%), SRSF2 (37.1%), NRAS (31.4%), and TET2 (25.7%) were frequently mutated, with lower frequencies of TET2 mutation and higher frequencies of NRAS, DNMT3A (17.1%), and NPM1 (11.4%) mutations compared to in previous studies of Caucasians. Patients with SETBP1 mutation and those with more than two variants showed poorer survival than those without mutation (P < 0.001 and P = 0.007, respectively). Most (70.8%) variants were detected at diagnosis and follow-up with no significant differences in variant allele frequency, warranting sequencing during follow-up if diagnostic samples were unavailable. Single-cell analysis revealed clonal monocytes with mutations, and the same mutations were also identified in lymphocytes and neutrophils. Targeted sequencing aided in clonality detection in most patients with CMML and single-cell sequencing facilitated identification of clonal monocytes and the co-existence of mutations in non-myeloid cells, suggesting that certain mutations are acquired by pluripotent stem cells.

Characteristics of bone marrow cell dysplasia and its effectiveness in diagnosing myelodysplastic syndrome

BACKGROUND

Although dysplasia plays an important role in the diagnosis of myelodysplasia syndrome (MDS), its morphologic variety and irregularity result in difficulties in its clinical application.

METHODS

Bone marrow smears from cases with MDS and non-clonal disease were collected and performed microscopy analysis. We respectively recorded the percentage of specific dysplastic cells (PSDC) and incidence of specific dysplasia (ISD) of each dysplastic type in three hematopoietic cell lineages for the comprehensive analysis of diagnostic efficacy to MDS.

RESULTS

Compared with non-clonal anemia, the PSDCs and ISDs of the four specific dysplastic types as petal nucleus and internuclear bridging in erythroid lineage, pseudo-Pelger-Huet in granulocytic lineage and lymphoid small megakaryocyte in megakaryocytic lineage were significantly higher in MDS; and their area under the curves were all greater than 0.600. If the dysplastic rate in each lineage was higher than 10%, their corresponding false positive rates (FPRs) were below 0.033, 1 × 10^-4 and 1 × 10^-4, respectively. If the dysplastic rates in three cell lineages reached 0.065, 0.045 and 0.040, respectively, their corresponding FPRs were all below 0.050.

CONCLUSION

Four specific dysplastic types possess higher diagnostic efficacy for the diagnosis of MDS. Though the dysplastic rate over 10% in any hematopoietic cell lineage presents a lower FPR, it is possibly considered to lower the diagnostic threshold of MDS if a specific dysplastic type with higher diagnostic efficacy presents.

Techniques for detecting chromosomal aberrations in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous hematologic diseases. Chromosomal aberrations are important for the initiation, development, and progression of MDS. Detection of chromosomal abnormalities in MDS is important for categorization, risk stratification, therapeutic selection, and prognosis evaluation of the disease. Recent progress of multiple techniques has brought powerful molecular cytogenetic information to reveal copy number variation, uniparental disomy, and complex chromosomal aberrations in MDS. In this review, we will introduce some common chromosomal aberrations in MDS and their clinical significance. Then we will explain the application, advantages, and limitations of different techniques for detecting chromosomal abnormalities in MDS. The information in this review may be helpful for clinicians to select appropriate methods in patient-related decision making.