Target Therapy for Extramedullary Relapse of FLT3-ITD Acute Myeloid Leukemia: Emerging Data from the Field.

FMS-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase family member. Mutations in FLT3, as well known, represent the most common genomic alteration in acute myeloid leukemia (AML), identified in approximately one-third of newly diagnosed adult patients. In recent years, this has represented an important therapeutic target. Drugs such as midostaurin, gilteritinib, and sorafenib, either alone in association with conventional chemotherapy, play a pivotal role in AML therapy with the mutated FLT3 gene. A current challenge lies in treating forms of AML with extramedullary localization. Here, we describe the general features of myeloid sarcoma and the ability of a targeted drug, i.e., gilteritinib, approved for relapsed or refractory disease, to induce remission of these extramedullary leukemic localizations in AML patients with FLT3 mutation, analyzing how in the literature, there is an important development of cases describing this promising potential for care.

Diagnostic test assessment. Validation study of an alternative system to detect microsatellite instability in colorectal carcinoma.

The American Society for Clinical Pathology (ASCP), College of American Pathologists (CAP), Association for Molecular Pathology (AMP), and the American Society of Clinical Oncology (ASCO) have been recently strongly recommended the evaluation of mismatch repair status (MMS) as molecular biomarkers in colorectal cancer for a better prognostic stratification of patients. This recommendation is emphasized by the recent evidence of Microsatellite Instability (MSI) as a predictive marker for chemotherapy and immunotherapy.In this scenario, the validation of molecular biomarker testing methods seems to be essential to design the most appropriate tailored therapy and the most suitable care strategy, respectively.In this study, we validated an alternative method based on capillary electrophoresis system label-free PCR (Qiaxcel system) to evaluate the MSI Bethesda Panel. We also parallel the results with a standard approach.Our data showed total concordance with the standard approach, with a highly time-efficient and easy procedure combined with high sensitivity for MSI detection.Alternative capillary electrophoresis based on label-free PCR such as the Qiaxel system is a very sensitive and specific method to detect MSI for the management of patients with colorectal cancer. This procedure is adequate and suitable in diagnostic routine for the evaluation of microsatellite repeats compared to standard procedures.

miR-155 regulative network in FLT3 mutated acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) represents a heterogeneous disorder with recurrent chromosomal alterations and molecular abnormalities. Among AML with normal karyotype (NK-AML) FLT3 activating mutation, internal tandem duplication (FLT3-ITD), is present in about 30% of patients, conferring unfavorable outcome. Our previous data demonstrated specific up-regulation of miR-155 in FLT3-ITD+ AML. miR-155 is known to be directly implicated in normal hematopoiesis and in some pathologies such as myeloid hyperplasia and acute lymphoblastic leukemia. METHODS AND RESULTS: To investigate about the potential influence of miR-155 de-regulation in FLT3-mutated AML we generated a transcription factors regulatory network and combined this with data from multiple sources that predict miR-155 interactions. From these analyses, we derived a sub-network, called "miR-155 module" that describes functional relationship among miR-155 and transcription factors in FLT3-mutated AML. We found that "miR-155 module" is characterized by the presence of six transcription factors as central hubs: four miR-155 regulators (JUN, RUNX1, FOSb, JUNB) and two targets of miR-155 (SPI1, CEBPB) all known to be "master" genes of myelopoiesis. We found, in FLT3-mutated AML, a significant down-regulation of miR-155 target genes CEBPB and SPI1 and up-regulation of miR-155 regulator genes JUN and RUNX1. We also showed that PKC412-related FLT3 inhibition, in MV4-11 cell line, causes down-regulation of miR-155 and increased level of mRNA and protein of miR-155 target SPI1. We showed in experiments of miR-155 mimic in K562 cell line, a high increase of miR-155 and an inverse correlation with the mRNA levels of its targets SPI1 and CEBPB. Moreover silencing of miR-155 in primary AMLs causes mRNA up-regulation of its target SPI1 and CEBPB. CONCLUSION: Our results suggest that activating mutation of FLT3 in AML can lead, through the induction of JUN, to an increased expression of miR-155, which then causes down-regulation of SPI1 and CEBPB and consequently may causes block of myeloid differentiation.

Endometrial expression of selected genes in patients achieving pregnancy spontaneously or after ICSI and patients failing at least two ICSI cycles.

The objective of this study was to identify the endometrial gene expression profile in receptive phase, which could represent a useful prognostic tool for selecting IVF patients. Endometrial expression of 47 selected genes biopsied during the window of implantation in natural cycles was compared between patients who achieved a successful pregnancy spontaneously or after subsequent intracytoplasmic sperm injection (ICSI) cycles and patients who did not achieve a pregnancy after at least two failed ICSI cycles. The comparative analysis showed significantly different levels of expression in 19 genes, five implicated in apoptosis (CASP8, FADD, CASP10, APAF1, ANXA4), three in immunity (LIF, SPP1, C4BPA), five in transcriptional activity (MSX1, HOXA10, MSX2, HOXA11, GATA2), two in lipid metabolism (LEPR, APOD) and four in oxidative metabolism (AOX1, ALDH1A3, GPX3, NNMT). The evidence for these genes being differently expressed could represent the starting point of identifying the ideal receptive endometrial gene expression profile, which could be used in the future as a prognostic tool for IVF patients. Gene expression analysis technology has opened new important perspectives on the study of the physiological processes of different tissues and organs. Specifically for the endometrium, it would be really interesting to find out an endometrial gene expression profile of receptive phase, which could be used in future as a useful prognostic tool for selecting IVF patients. To achieve this aim, the objective of the present paper was the comparison of endometrial expression in natural cycles of 47 selected genes between the biopsies of patients who achieved a successful pregnancy, either spontaneously or after subsequent ICSI cycles, and those of patients who did not achieve a pregnancy after at least two failed ICSI cycles. The comparative analysis showed a significant different expression in 19 genes: five implicated in programmed cell death, known as apoptosis (CASP8, FADD, CASP10, APAF1, ANXA4), three in immunity (LIF, SPP1, C4BPA), five in transcriptional activity (MSX1, HOXA10, MSX2, HOXA11, GATA2), two in lipid metabolism (LEPR, APOD) and four in oxidative metabolism (AOX1, ALDH1A3, GPX3, NNMT). The evidence of these genes being differently expressed could represent the starting point of identifying the ideal receptive endometrial gene expression profile which could be used in the future as a prognostic tool for IVF patients.

14q32/miRNA clusters loss of heterozygosity in acute lymphoblastic leukemia is associated with up-regulation of BCL11a.

This study evaluated the loss and expression level of miRNAs 14q32 clusters in acute lymphoblastic leukemia (ALL) patients with cryptic deletions at 14q32 chromosomal band to investigate their involvement in this disease. We demonstrate that a subset of ALL cases bearing 14q32 LOH showed a down-regulation of miRNA 14q32 clusters, which is directly linked to the submicroscopic chromosomal deletion. As a consequence of miRNAs deregulation we reported an inverse correlation with the expression of their target BCL11a, a transcription factor involved in lymphoid differentiation. These results suggest that 14q32/miRNA clusters LOH may be another mechanism involved in lymphoid B cell transformation and differentiation and therefore, could be used as a diagnostic marker and therapeutic target in subsets of ALL.

Differential expression of specific microRNA and their targets in acute myeloid leukemia.

Acute myeloid leukemia (AML) the most common acute leukemia in adults is characterized by various cytogenetic and molecular abnormalities. However, the genetic etiology of the disease is not yet fully understood. MicroRNAs (miRNA) are small noncoding RNAs which regulate the expression of target mRNAs both at transcriptional and translational level. In recent years, miRNAs have been identified as a novel mechanism in gene regulation, which show variable expression during myeloid differentiation. We studied miRNA expression of leukemic blasts of 29 cases of newly diagnosed and genetically defined AML using quantitative reverse transcription polymerase chain reaction (RT-PCR) for 365 human miRNA. We showed that miRNA expression profiling reveals distinctive miRNA signatures that correlate with cytogenetic and molecular subtypes of AML. Specific miRNAs with consolidated role on cell proliferation and differentiation such as miR-155, miR-221, let-7, miR-126 and miR-196b appear to be associated with particular subtypes. We observed a significant differentially expressed miRNA profile that characterizes two subgroups of AML with different mechanism of leukemogenesis: core binding factor (CBF) and cytogenetically normal AML with mutations in the genes of NPM1 and FLT3-ITD. We demonstrated, for the first time, the inverse correlation of expression levels between miRNA and their targets in specific AML genetic groups. We suggest that miRNA deregulation may act as complementary hit in the multisteps mechanism of leukemogenesis offering new therapeutic strategies.

Loss of heterozygosity in acute leukemia: evidence of frequent submicroscopic deletions.

Although chromosomal abnormalities are detected by conventional cytogenetic analysis (CCA) in 40-60% of patients with acute myeloid leukemia (AML), cryptic chromosomal deletions may only be detected by molecular analysis. To determine their frequency, we studied 74 cases of AML by microsatellite allelotype assay using 35 microsatellites spanning eight chromosomal regions known to be frequently involved in AML. In 42 (57%) we found DNA imbalance at the screened loci. This was detected by CCA only in 4 cases. Our data show that cryptic deletions are a common event in AML.

Localization of HSP70, Cdc2, and cyclin B in sea urchin oocytes in non-stressed conditions.

In Paracentrotus lividus embryos, a Mediterranean sea urchin species, HSP70 is present in all the cells. During cell division it localizes under normal growth conditions on the centrosomes and on the whole isolated mitotic apparatus. Now, in situ hybridization, Western blot analyses, and immunohistochemistry show that the HSP70 mRNA is present in both small and large P. lividus oocytes, that all four isoforms of HSP70 can be found also in the oocytes, and that a certain amount of HSP70 localizes on asters and spindles during polar body formation. Moreover, two representative cell-cycle related proteins, cyclin B, and Cdc2, are present both in small and large oocytes, concentrating in the germinal vesicles before its breaking down. Cdc2 has been found in the cytoplasm of small oocytes and in the germinal vesicles of the large ones and then together with HSP70 on the mitotic apparatus of the dividing oocytes.