Retrospective Analysis of Clinical Factors Relating to the Outcome of Gemtuzumab Ozogamicin Therapy

It is difficult to predict the clinical outcome of gemtuzumab ozogamicin (GO) therapy based solely on the previously identified predictive factors. We retrospectively analyzed the relationship between clinical factors and outcomes in 12 patients with relapsed or refractory acute leukemia who received GO monotherapy. The median patient age at initial GO infusion was 56 years, and the average initial dosage was 8.1 mg/m2. Four patients (33%) achieved an overall remission (OR). The time from diagnosis to GO infusion was significantly longer in patients with OR than in patients with no remission (NR)(1747 vs. 501 days, respectively; P < 0.01). The number of karyotype abnormalities before GO infusion was significantly greater in NR patients (9.5) than in OR patients (0.5; P = 0.03). Monocyte counts in the bone marrow before GO therapy were significantly lower in OR than in NR patients (100/μL vs. 1080/μL, respectively; P = 0.048). In a multivariate analysis, monocyte count was significantly associated with overall survival (P = 0.005). CD14 expression in OR patients was lower than in NR patients, with the exception of 4 patients whose French-American-British subtypes were M4 or M5 (OR, 0.3%; NR, 2.5%; P = 0.04). NR was noted in all 6 patients who underwent allogeneic stem cell transplantation before and/or after GO infusion. Patients showing good sensitivity to conventional chemotherapy with good survival after diagnosis tend to be sensitive to GO as well. A low monocyte count in the bone marrow at infusion of GO might indicate improved efficacy of GO therapy. Further investigation is warranted for establishing appropriate patient selection and for clarifying efficient conditions for GO therapy

Reduction of N-Glycolylneuraminic Acid in Human Induced Pluripotent Stem Cells Generated or Cultured under Feeder- and Serum-Free Defined Conditions

BACKGROUND: The successful establishment of human induced pluripotent stem cells (hiPSCs) has increased the possible applications of stem cell research in biology and medicine. In particular, hiPSCs are a promising source of cells for regenerative medicine and pharmacology. However, one of the major obstacles to such uses for hiPSCs is the risk of contamination from undefined pathogens in conventional culture conditions that use serum replacement and mouse embryonic fibroblasts as feeder cells. METHODOLOGY/PRINCIPAL FINDINGS: Here we report a simple method for generating or culturing hiPSCs under feeder- and serum-free defined culture conditions that we developed previously for human embryonic stem cells. The defined culture condition comprises a basal medium with a minimal number of defined components including five highly purified proteins and fibronectin as a substrate. First, hiPSCs, which were generated using Yamanaka's four factors and conventional undefined culture conditions, adapted to the defined culture conditions. These adapted cells retained the property of self renewal as evaluated morphologically, the expression of self-renewal marker proteins, standard growth rates, and pluripotency as evaluated by differentiation into derivatives of all three primary germ layers in vitro and in vivo (teratoma formation in immunodeficient mice). Moreover, levels of nonhuman N-glycolylneuraminic acid (Neu5Gc), which is a xenoantigenic indicator of pathogen contamination in human iPS cell cultures, were markedly decreased in hiPSCs cultured under the defined conditions. Second, we successfully generated hiPSCs using adult dermal fibroblast under the defined culture conditions from the reprogramming step. For a long therm culture, the generated cells also had the property of self renewal and pluripotency, they carried a normal karyotype, and they were Neu5Gc negative. CONCLUSION/SIGNIFICANCE: This study suggested that generation or adaption culturing under defined culture conditions can eliminate the risk posed by undefined pathogens. This success in generating hiPSCs using adult fibroblast would be beneficial for clinical application

Multinucleation followed by an acytokinetic cell division in myxofibrosarcoma with giant cell proliferation

<p>Abstract</p> <p>Background</p> <p>Multinucleated cells are frequently seen in association with a malignant neoplasm. Some of these multinucleated cells are considered to be neoplastic. The mechanism of neoplastic multinucleation remains unknown, but is considered to be induced by either cell-cell fusion or acytokinetic cell division. Myxofibrosarcoma consists of spindled and pleomorphic tumor cells and bizarre multinucleated giant cells. Some of these multinucleated cells are considered to be neoplastic.</p> <p>Methods</p> <p>We studied the mitotic activity of the multinucleated cells by Ki-67 immunohistochemistry, and the dynamics and differentiation by live-cell video microscopy in the two myxofibrosarcoma cell lines to determine whether the mechanism of multinucleation is cell-cell fusion or acytokinetic cell division</p> <p>Results</p> <p>A Ki-67 immunohistochemical analysis revealed a high positive rate of multinucleated cells, as well as mononuclear cells, and mitotic ability was shown in the multinucleated cells. In live-cell video microscopy, most of the multinucleated cells were induced via the process of acytokinetic cell division.</p> <p>Conclusion</p> <p>The current study indicates that a vulnerability of the cytoskeleton components, such as the contractile ring, causes multinucleation to occur from the telophase to the cytokinesis of the cell cycle.</p

Mast Cell Infiltration is Associated with Myelofibrosis and Angiogenesis in Myelodysplastic Syndromes

Myelodysplastic syndromes are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by persistent peripheral cytopenia with morphological and functional abnormalities of hematopoietic cells. Mast cells infiltrate into or around tumor tissues and play a role in remodeling of the stromal microenvironment, contributing to tumor progression. Increased mast cell numbers are associated with fibrosis, angiogenesis and a poor prognosis in human carcinomas. The aim of this study was to determine whether mast cell infiltration contributes to myelofibrosis or angiogenesis in myelodysplastic syndromes. We evaluated the correlation between mast cell density and the extent of myelofibrosis and angiogenesis in myelodysplastic syndromes. Fifty bone marrow biopsies taken from patients with a diagnosis of myelodysplastic syndromes were examined. Grading of myelofibrosis was evaluated by silver impregnation staining. Mast cell density and microvessel density were evaluated by immunohistochemistry. Human mast cells have been divided into two phenotypes. We designated a tryptase-positive mast cell as MCT and a chymase-positive mast cell as MCTC. Microvessels were identified by CD34-positive endothelial cells. Microvessel density and the extent of myelofibrosis were significantly greater in patients with high MCT and MCTC density compared to those with low MC density. Based on this, we suggest that the presence of high mast cell numbers is associated with myelofibrosis and angiogenesis in myelodysplastic syndromes

Novel quantitative immunohistochemical analysis for evaluating PD-L1 expression with phosphor-integrated dots for predicting the efficacy of patients with cancer treated with immune checkpoint inhibitors

IntroductionProgrammed cell death ligand 1 (PD-L1) expression in tumor tissues is measured as a predictor of the therapeutic efficacy of immune checkpoint inhibitors (ICIs) in many cancer types. PD-L1 expression is evaluated by immunohistochemical staining using 3,3´-diaminobenzidine (DAB) chronogenesis (IHC-DAB); however, quantitative and reproducibility issues remain. We focused on a highly sensitive quantitative immunohistochemical method using phosphor-integrated dots (PIDs), which are fluorescent nanoparticles, and evaluated PD-L1 expression between the PID method and conventional DAB method.MethodsIn total, 155 patients with metastatic or recurrent cancer treated with ICIs were enrolled from four university hospitals. Tumor tissue specimens collected before treatment were subjected to immunohistochemical staining with both the PID and conventional DAB methods to evaluate PD-L1 protein expression.ResultsPD-L1 expression assessed using the PID and DAB methods was positively correlated. We quantified PD-L1 expression using the PID method and calculated PD-L1 PID scores. The PID score was significantly higher in the responder group than in the non-responder group. Survival analysis demonstrated that PD-L1 expression evaluated using the IHC-DAB method was not associated with progression-free survival (PFS) or overall survival (OS). Yet, PFS and OS were strikingly prolonged in the high PD-L1 PID score group.ConclusionQuantification of PD-L1 expression as a PID score was more effective in predicting the treatment efficacy and prognosis of patients with cancer treated with ICIs. The quantitative evaluation of PD-L1 expression using the PID method is a novel strategy for protein detection. It is highly significant that the PID method was able to identify a group of patients with a favorable prognosis who could not be identified by the conventional DAB method

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Control of Cell Differentiation and Morphogenesis by Activin A during Early Amphibian Development

報告番号: 甲11724 ; 学位授与年月日: 1996-03-29 ; 学位の種別: 課程博士 ; 学位の種類: 博士(理学) ; 学位記番号: 博理第3088号 ; 研究科・専攻: 理学系研究科生物科学専

アクチビンAによる両生類の初期発生における細胞分化および形態形成の制御

University of Tokyo (東京大学