A prenatal case with multiple supernumerary markers identified as derivatives of chromosomes 13, 15, and 20: molecular cytogenetic characterization and review of the literature.

Multiple small supernumerary marker chromosomes (sSMCs) are among the rarest cytogenetic abnormalities as they represent roughly 1.4% of cases with sSMCs. We report on a prenatal case presenting de novo multiple sSMCs; these sSMCs were characterized by array CGH and FISH and resulted deriving from three different chromosomes: a der(13), a der(15) and a der(20). The co-presence of der(13), der(20), and der(15) have not been reported yet. The clinical consequences of this marker combination cannot be precisely predicted. However, according to the publicly available databases, the partial trisomies of chromosome 13 and 20 have probably a pathogenic effect. It is worth noting that a cooperative effect, due to interactions among genes harbored on the three derivatives, cannot be excluded, making the genetic counseling challenging.

Morphologic and immunophenotypic features of a case of acute monoblastic leukemia with unusual positivity for Glycophorin-A.

Acute monoblastic leukemia (AMoL) is characterized by cells with highly undifferentiated morphology. Cytochemistry with non-specific esterases is negative in up to 20% of cases. Immunophenotyping by flow cytometry has an essential role in diagnosing such a subtype of leukemia and a multiparametric approach with a wide monoclonal antibody panel is necessary. We describe a case of AMoL with morphology resembling either plasma blasts or very immature erythroblasts. Diagnosis was made by alpha-naphtyl-acetate esterase staining and with immunophenotyping, which was made with a wide monoclonal antibody panel. Blasts were positive for monocytic markers. Most of leukemic cells, however, were positive for Glycophorin-A. The presence of Glycophorin-A, which is considered as a specific marker of the erythroid lineage, has never been reported previously in cases of AMoL. This peculiar immunophenotype might be interpreted as deriving from a common myelo-erythroid precursor undergone leukemic transformation.

The Polycomb BMI1 Protein Is Co-expressed With CD26+ in Leukemic Stem Cells of Chronic Myeloid Leukemia.

The Polycomb gene BMI1 expression exerts a negative predictive impact on several hematological malignancies, such as acute and chronic myeloid leukemia (CML), myelofibrosis, and follicular lymphoma. As already demonstrated in CML, BMI1 is responsible for the resistance to the tyrosine kinase inhibitors (TKIs) in a BCR-ABL1-independent way. Even if, it is unknown where BMI1 in CML is expressed (in progenitors or more mature cells). We decided, therefore, to evaluate if and where the BMI1 protein is located, focusing mainly on the CD34+/CD38-/CD26+ CML progenitors. To begin we measured, by flow cytometry, the proportion of CD34+/CD26+ cells in 31 bone marrow samples from 20 CML patients, at diagnosis and during treatment with imatinib. After that the bone marrow blood smears were stained with antibodies anti-CD26, BCR-ABL1, and BMI1. These smears were observed by a confocal laser microscope and a 3D reconstruction was then performed. At diagnosis, CD34+/CD26+ cells median value/µL was 0.48; this number increased from diagnosis to the third month of therapy and then reduced during treatment with imatinib. The number and behavior of the CD26+ progenitors were independent from the BCR-ABL1 expression, but they summed up what previously observed about the BMI1 expression modulation. In this work we demonstrate for the first time that in CML the BMI1 protein is co-expressed with BCR-ABL1 only in the cytoplasm of the CD26+ precursors; on the contrary, in other hematological malignancies where BMI1 is commonly expressed (follicular lymphoma, essential thrombocytemia, acute myeloid leukemia), it was not co-localized with CD26 or, obviously, with BCR-ABL1. Once translated into the clinical context, if BMI1 is a marker of stemness, our results would suggest the combination of the BMI1 inhibitors with TKIs as an interesting object of research, and, probably, as a promising way to overcome resistance in CML patients.

Myelodysplastic syndromes: advantages of a combined cytogenetic and molecular diagnostic workup.

In this study we present a new diagnostic workup for the myelodysplastic syndromes (MDS) including FISH, aCGH, and somatic mutation assays in addition to the conventional cytogenetics (CC). We analyzed 61 patients by CC, FISH for chromosome 5, 7, 8 and PDGFR rearrangements, aCGH, and PCR for ASXL1, EZH2, TP53, TET2, RUNX1, DNMT3A, SF3B1 somatic mutations. Moreover, we quantified WT1 and RPS14 gene expression levels, in order to find their possible adjunctive value and their possible clinical impact. CC analysis showed 32% of patients with at least one aberration. FISH analysis detected chromosomal aberrations in 24% of patients and recovered 5 cases (13.5%) at normal karyotype (two 5q- syndromes, one del(7) case, two cases with PDGFR rearrangement). The aGCH detected 10 "new" unbalanced cases in respect of the CC, including one with alteration of the ETV6 gene. After mutational analysis, 33 patients (54%) presented at least one mutation and represented the only marker of clonality in 36% of all patients. The statistical analysis confirmed the prognostic role of CC either on overall or on progression-free-survival. In addition, deletions detected by aCGH and WT1 over-expression negatively conditioned survival. In conclusion, our work showed that 1) the addition of FISH (at least for chr. 5 and 7) can improve the definition of the risk score; 2) mutational analysis, especially for the TP53 and SF3B1, could better define the type of MDS and represent a "clinical warning"; 3) the aCGH use could be probably applied to selected cases (with suboptimal response or failure).

Myelomatous meningitis evaluated by multiparameter flow cytometry : report of a case and review of the literature.

Central nervous system (CNS) involvement in multiple myeloma (MM) is uncommon. Among its possible presentations, leptomeningeal involvement of MM, also termed central nervous system myelomatosis (CNS-MM) is rare and is characterized by the presence of neoplastic plasma cells in the cerebrospinal fluid (CSF). So far, 187 cases of CNS-MM have been reported : the great majority of them were diagnosed by cytological assays and flow cytometry was used in only eight cases. We describe a case of CNS-MM in a 62-year-old woman, previously treated with chemotherapy (VTD) and autologous peripheral blood hematopoietic stem cell transplantation for stage IIIB IgG-λ MM. After achieving a very good partial response, the patient showed progression of disease, with an extramedullary localization. During administration of second-line therapy, the patient showed severe neurological symptoms. MRI resulted negative. Diagnosis of CNS-MM was made by multiparameter flow cytometry, which showed the presence of CD56(+) plasma cells in a CSF sample, in the absence of plasma cell leukemia. In this paper we also present a review of the eight previous cases of CNS-MM diagnosed by flow cytometry. We found that the application of flow cytometry in cases of MM with neurological symptoms allows a rapid diagnosis of CNS-MM and provides useful information about plasma cell phenotype (including CD56 expression). Some cases of CNS-MM are characterized by normal MRI. In addition, some evidences deriving from the review of literature suggest that CSF monitoring by flow cytometry in such cases might be used to evaluate the efficacy of drugs capable of crossing the blood-brain barrier.