Periportal macrophages protect against commensal-driven liver inflammation.

The liver is the main gateway from the gut, and the unidirectional sinusoidal flow from portal to central veins constitutes heterogenous zones, including the periportal vein (PV) and the pericentral vein zones1-5. However, functional differences in the immune system in each zone remain poorly understood. Here intravital imaging revealed that inflammatory responses are suppressed in PV zones. Zone-specific single-cell transcriptomics detected a subset of immunosuppressive macrophages enriched in PV zones that express high levels of interleukin-10 and Marco, a scavenger receptor that sequesters pro-inflammatory pathogen-associated molecular patterns and damage-associated molecular patterns, and consequently suppress immune responses. Induction of Marco+ immunosuppressive macrophages depended on gut microbiota. In particular, a specific bacterial family, Odoribacteraceae, was identified to induce this macrophage subset through its postbiotic isoallolithocholic acid. Intestinal barrier leakage resulted in inflammation in PV zones, which was markedly augmented in Marco-deficient conditions. Chronic liver inflammatory diseases such as primary sclerosing cholangitis (PSC) and non-alcoholic steatohepatitis (NASH) showed decreased numbers of Marco+ macrophages. Functional ablation of Marco+ macrophages led to PSC-like inflammatory phenotypes related to colitis and exacerbated steatosis in NASH in animal experimental models. Collectively, commensal bacteria induce Marco+ immunosuppressive macrophages, which consequently limit excessive inflammation at the gateway of the liver. Failure of this self-limiting system promotes hepatic inflammatory disorders such as PSC and NASH.

Single-cell transcriptomics of human cholesteatoma identifies an activin A-producing osteoclastogenic fibroblast subset inducing bone destruction.

Cholesteatoma, which potentially results from tympanic membrane retraction, is characterized by intractable local bone erosion and subsequent hearing loss and brain abscess formation. However, the pathophysiological mechanisms underlying bone destruction remain elusive. Here, we performed a single-cell RNA sequencing analysis on human cholesteatoma samples and identify a pathogenic fibroblast subset characterized by abundant expression of inhibin ßA. We demonstrate that activin A, a homodimer of inhibin ßA, promotes osteoclast differentiation. Furthermore, the deletion of inhibin ßA /activin A in these fibroblasts results in decreased osteoclast differentiation in a murine model of cholesteatoma. Moreover, follistatin, an antagonist of activin A, reduces osteoclastogenesis and resultant bone erosion in cholesteatoma. Collectively, these findings indicate that unique activin A-producing fibroblasts present in human cholesteatoma tissues are accountable for bone destruction via the induction of local osteoclastogenesis, suggesting a potential therapeutic target.

In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma.

Alveolar macrophages (AMs) are crucial for maintaining normal lung function. They are abundant in lung cancer tissues, but their pathophysiological significance remains unknown. Here we show, using an orthotopic murine lung cancer model and human carcinoma samples, that AMs support cancer cell proliferation and thus contribute to unfavourable outcome. Inhibin beta A (INHBA) expression is upregulated in AMs under tumor-bearing conditions, leading to the secretion of activin A, a homodimer of INHBA. Accordingly, follistatin, an antagonist of activin A is able to inhibit lung cancer cell proliferation. Single-cell RNA sequence analysis identifies a characteristic subset of AMs specifically induced in the tumor environment that are abundant in INHBA, and distinct from INHBA-expressing AMs in normal lungs. Moreover, postnatal deletion of INHBA/activin A could limit tumor growth in experimental models. Collectively, our findings demonstrate the critical pathological role of activin A-producing AMs in tumorigenesis, and provides means to clearly distinguish them from their healthy counterparts.

Label-free multiphoton excitation imaging as a promising diagnostic tool for breast cancer.

Histopathological diagnosis is the ultimate method of attaining the final diagnosis; however, the observation range is limited to the two-dimensional plane, and it requires thin slicing of the tissue, which limits diagnostic information. To seek solutions for these problems, we proposed a novel imaging-based histopathological examination. We used the multiphoton excitation microscopy (MPM) technique to establish a method for visualizing unfixed/unstained human breast tissues. Under near-infrared ray excitation, fresh human breast tissues emitted fluorescent signals with three major peaks, which enabled visualizing the breast tissue morphology without any fixation or dye staining. Our study using human breast tissue samples from 32 patients indicated that experienced pathologists can estimate normal or cancerous lesions using only these MPM images with a kappa coefficient of 1.0. Moreover, we developed an image classification algorithm with artificial intelligence that enabled us to automatically define cancer cells in small areas with a high sensitivity of ≥0.942. Taken together, label-free MPM imaging is a promising method for the real-time automatic diagnosis of breast cancer.

Pharmacoeconomic study of biologics for psoriasis treatment based on real-world drug survival.

The efficacy of biologics in psoriasis treatment is clinically proven; however, biologics are expensive. In this study, we assessed the real-world cost-effectiveness of biologics for psoriasis treatment by evaluating the relationship between biologic drug survival (DS) and total medical-treatment costs from a pharmacoeconomic viewpoint. Furthermore, the effects of patient factors on cost-effectiveness were investigated. We retrospectively reviewed the medical records of 135 cases who received either a tumor necrosis factor-alpha (TNF-α) monoclonal antibody (TNF-mab), interleukin (IL)-17 mab, or IL23p19-mab for psoriasis from January 2010 to June 2020 at Yamaguchi University Hospital. We compared the monthly medical-treatment costs according to biologic classification and found that costs of medical services, tests, and external preparations required for the treatment process were significantly higher in the TNF-mab group than in the other groups, and the total medical costs associated with TNF-mab treatment were significantly higher than those of IL17-mab treatment. The total monthly cost of medical care was lower in the long-term DS group than in the short-term group. The number of prescriptions for external preparations, comprising Vitamin D3 and corticosteroid, was significantly higher in the long-term DS group than in the short-term group; in the TNF-mab group, the proportion of patients without smoking habits was significantly higher in the long-term group as well. Our study indicated that when costly biologics are used for psoriasis treatment, the maintenance of long-term DS and appropriate patient guidance might improve the quality of medical care, thus allowing cost-effective medical care.

Nonmuscle myosin 2 regulates cortical stability during sprouting angiogenesis.

Among the three nonmuscle myosin 2 (NM2) paralogs, NM 2A and 2B, but not 2C, are detected in endothelial cells. To study the role of NM2 in vascular formation, we ablate NM2 in endothelial cells in mice. Ablating NM2A, but not NM2B, results in reduced blood vessel coverage and increased vascular branching in the developing mouse skin and coronary vasculature. NM2B becomes essential for vascular formation when NM2A expression is limited. Mice ablated for NM2B and one allele of NM2A develop vascular abnormalities similar to those in NM2A ablated mice. Using the embryoid body angiogenic sprouting assay in collagen gels reveals that NM2A is required for persistent angiogenic sprouting by stabilizing the endothelial cell cortex, and thereby preventing excessive branching and ensuring persistent migration of the endothelial sprouts. Mechanistically, NM2 promotes focal adhesion formation and cortical protrusion retraction during angiogenic sprouting. Further studies demonstrate the critical role of Rho kinase-activated NM2 signaling in the regulation of angiogenic sprouting in vitro and in vivo.

Local sympathetic neurons promote neutrophil egress from the bone marrow at the onset of acute inflammation.

The sympathetic nervous system plays critical roles in the differentiation, maturation and recruitment of immune cells under homeostatic conditions, and in responses to environmental stimuli, although its role in the migratory control of immune cells during acute inflammation remains unclear. In this study, using an advanced intravital bone imaging system established in our laboratory, we demonstrated that the sympathetic nervous system locally regulates neutrophil egress from the bone marrow for mobilization to inflammatory foci. We found that sympathetic neurons were located close to blood vessels in the bone marrow cavity; moreover, upon lipopolysaccharide (LPS) administration, local sympathectomy delayed neutrophil egress from the bone marrow and increased the proportion of neutrophils that remained in place. We also showed that vascular endothelial cells produced C-X-C motif chemokine ligand 1 (CXCL1), which is responsible for neutrophil egress out of the bone marrow. Its expression was up-regulated during acute inflammation, and was suppressed by ß-adrenergic receptor blockade, which was accompanied with inhibition of neutrophil egress into the systemic circulation. Furthermore, systemic ß-adrenergic signaling blockade decreased the recruitment of neutrophils in the lung under conditions of acute systemic inflammation. Taken together, the results of this study first suggested a new regulatory system, wherein local sympathetic nervous activation promoted neutrophil egress by enhancing Cxcl1 expression in bone marrow endothelial cells in a ß-adrenergic signaling-dependent manner, contributing to the recruitment of neutrophils at the onset of inflammation in vivo.

Tissue Myeloid Progenitors Differentiate into Pericytes through TGF-ß Signaling in Developing Skin Vasculature.

Mural cells (pericytes and vascular smooth muscle cells) are essential for the regulation of vascular networks and maintenance of vascular integrity, but their origins are diverse in different tissues and not known in the organs that arise from the ectoderm, such as skin. Here, we show that tissue-localized myeloid progenitors contribute to pericyte development in embryonic skin vasculature. A series of in vivo fate-mapping experiments indicates that tissue myeloid progenitors differentiate into pericytes. Furthermore, depletion of tissue myeloid cells and their progenitors in PU.1 (also known as Spi1) mutants results in defective pericyte development. Fluorescence-activated cell sorting (FACS)-isolated myeloid cells and their progenitors from embryonic skin differentiate into pericytes in culture. At the molecular level, transforming growth factor-ß (TGF-ß) induces pericyte differentiation in culture. Furthermore, type 2 TGF-ß receptor (Tgfbr2) mutants exhibit deficient pericyte development in skin vasculature. Combined, these data suggest that pericytes differentiate from tissue myeloid progenitors in the skin vasculature through TGF-ß signaling.

Foxc1 and Foxc2 deletion causes abnormal lymphangiogenesis and correlates with ERK hyperactivation.

The lymphatic vasculature is essential for maintaining interstitial fluid homeostasis, and dysfunctional lymphangiogenesis contributes to various pathological processes, including inflammatory disease and tumor metastasis. Mutations in FOXC2 are dominantly associated with late-onset lymphedema; however, the precise role of FOXC2 and a closely related factor, FOXC1, in the lymphatic system remains largely unknown. Here we identified a molecular cascade by which FOXC1 and FOXC2 regulate ERK signaling in lymphatic vessel growth. In mice, lymphatic endothelial cell-specific (LEC-specific) deletion of Foxc1, Foxc2, or both resulted in increased LEC proliferation, enlarged lymphatic vessels, and abnormal lymphatic vessel morphogenesis. Compared with LECs from control animals, LECs from mice lacking both Foxc1 and Foxc2 exhibited aberrant expression of Ras regulators, and embryos with LEC-specific deletion of Foxc1 and Foxc2, alone or in combination, exhibited ERK hyperactivation. Pharmacological ERK inhibition in utero abolished the abnormally enlarged lymphatic vessels in FOXC-deficient embryos. Together, these results identify FOXC1 and FOXC2 as essential regulators of lymphangiogenesis and indicate a new potential mechanistic basis for lymphatic-associated diseases.

Temporal-specific roles of Rac1 during vascular development and retinal angiogenesis.

Angiogenesis, the formation of new blood vessels by remodeling and growth of pre-existing vessels, is a highly orchestrated process that requires a tight balance between pro-angiogenic and anti-angiogenic factors and the integration of their corresponding signaling networks. The family of Rho GTPases, including RhoA, Rac1, and Cdc42, play a central role in many cell biological processes that involve cytoskeletal changes and cell movement. Specifically for Rac1, we have shown that excision of Rac1 using a Tie2-Cre animal line results in embryonic lethality in midgestation (embryonic day (E) 9.5), with multiple vascular defects. However, Tie2-Cre can be also expressed during vasculogenesis, prior to angiogenesis, and is active in some hematopoietic precursors that can affect vessel formation. To circumvent these limitations, we have now conditionally deleted Rac1 in a temporally controlled and endothelial-restricted fashion using Cdh5(PAC)-iCreERT2 transgenic mice. In this highly controlled experimental in vivo system, we now show that Rac1 is required for embryonic vascular integrity and angiogenesis, and for the formation of superficial and deep vascular networks in the post-natal developing retina, the latter involving a novel specific function for Rac1 in vertical blood vessel sprouting. Aligned with these findings, we show that RAC1 is spatially involved in endothelial cell migration, invasion, and radial sprouting activities in 3D collagen matrix in vitro models. Hence, Rac1 and its downstream molecules may represent potential anti-angiogeneic therapeutic targets for the treatment of many human diseases that involve aberrant neovascularization and blood vessel overgrowth.

Characterizing the angiogenic activity of patients with single ventricle physiology and aortopulmonary collateral vessels.

OBJECTIVES: Patients with single ventricle congenital heart disease often form aortopulmonary collateral vessels via an unclear mechanism. To gain insights into the pathogenesis of aortopulmonary collateral vessels, we correlated angiogenic factor levels with in vitro activity and angiographic aortopulmonary collateral assessment and examined whether patients with single ventricle physiology have increased angiogenic factors that can stimulate endothelial cell sprouting in vitro. METHODS: In patients with single ventricle physiology (n = 27) and biventricular acyanotic control patients (n = 21), hypoxia-inducible angiogenic factor levels were measured in femoral venous and arterial plasma at cardiac catheterization. To assess plasma angiogenic activity, we used a 3-dimensional in vitro cell sprouting assay that recapitulates angiogenic sprouting. Aortopulmonary collateral angiograms were graded using a 4-point scale. RESULTS: Compared with controls, patients with single ventricle physiology had increased vascular endothelial growth factor (artery: 58.7 ± 1.2 pg/mL vs 35.3 ± 1.1 pg/mL, P < .01; vein: 34.8 ± 1.1 pg/mL vs 21 ± 1.2 pg/mL, P < .03), stromal-derived factor 1-alpha (artery: 1901.6 ± 1.1 pg/mL vs 1542.6 ± 1.1 pg/mL, P < .03; vein: 2092.8 pg/mL ± 1.1 vs 1752.9 ± 1.1 pg/mL, P < .02), and increased arterial soluble fms-like tyrosine kinase-1, a regulatory vascular endothelial growth factor receptor (612.3 ± 1.2 pg/mL vs 243.1 ± 1.2 pg/mL, P < .003). Plasma factors and sprout formation correlated poorly with aortopulmonary collateral severity. CONCLUSIONS: We are the first to correlate plasma angiogenic factor levels with angiography and in vitro angiogenic activity in patients with single ventricle disease with aortopulmonary collaterals. Patients with single ventricle disease have increased stromal-derived factor 1-alpha and soluble fms-like tyrosine kinase-1, and their roles in aortopulmonary collateral formation require further investigation. Plasma factors and angiogenic activity correlate poorly with aortopulmonary collateral severity in patients with single ventricles, suggesting complex mechanisms of angiogenesis.

Peripheral nerve-derived CXCL12 and VEGF-A regulate the patterning of arterial vessel branching in developing limb skin.

In developing limb skin, peripheral nerves provide a spatial template that controls the branching pattern and differentiation of arteries. Our previous studies indicate that nerve-derived VEGF-A is required for arterial differentiation but not for nerve-vessel alignment. In this study, we demonstrate that nerve-vessel alignment depends on the activity of Cxcl12-Cxcr4 chemokine signaling. Genetic inactivation of Cxcl12-Cxcr4 signaling perturbs nerve-vessel alignment and abolishes arteriogenesis. Further in vitro assays allow us to uncouple nerve-vessel alignment and arteriogenesis, revealing that nerve-derived Cxcl12 stimulates endothelial cell migration, whereas nerve-derived VEGF-A is responsible for arterial differentiation. These findings suggest a coordinated sequential action in which nerve Cxcl12 functions over a distance to recruit vessels to align with nerves, and subsequent arterial differentiation presumably requires a local action of nerve VEGF-A in the nerve-associated vessels.

Conditional deletion of Ccm2 causes hemorrhage in the adult brain: a mouse model of human cerebral cavernous malformations.

Cerebral cavernous malformations (CCM) are irregularly shaped and enlarged capillaries in the brain that are prone to hemorrhage, resulting in headaches, seizures, strokes and even death in patients. The disease affects up to 0.5% of the population and the inherited form has been linked to mutations in one of three genetic loci, CCM1, CCM2 and CCM3. To understand the pathophysiology underlying the vascular lesions in CCM, it is critical to develop a reproducible mouse genetic model of this disease. Here, we report that limited conditional ablation of Ccm2 in young adult mice induces observable neurological dysfunction and reproducibly results in brain hemorrhages whose appearance is highly reminiscent of the lesions observed in human CCM patients. We first demonstrate that conventional or endothelial-specific deletion of Ccm2 leads to fatal cardiovascular defects during embryogenesis, including insufficient vascular lumen formation as well as defective arteriogenesis and heart malformation. These findings confirm and extend prior studies. We then demonstrate that the inducible deletion of Ccm2 in adult mice recapitulates the CCM-like brain lesions in humans; the lesions display disrupted vascular lumens, enlarged capillary cavities, loss of proper neuro-vascular associations and an inflammatory reaction. The CCM lesions also exhibit damaged neuronal architecture, the likely cause of neurologic defects, such as ataxia and seizure. These mice represent the first CCM2 animal model for CCM and should provide the means to elucidate disease mechanisms and evaluate therapeutic strategies for human CCM.

Gli3 is required for maintenance and fate specification of cortical progenitors.

Gli3, one of three vertebrate Gli transcription factors in Hedgehog (Hh) pathway, is processed into a repressor form (Gli3R) in the absence of Hh signal and acts as the major negative transducer of the pathway. Although the role of Gli3 in embryonic patterning has been extensively studied, its role in cortical neurogenesis, especially in the regulation of neural progenitors in proliferation and cell fate specification, is largely unknown. To bypass the patterning defects caused by loss of Gli3, we conditionally deleted Gli3 after patterning was complete in mouse. Our results from birthdating and in utero electroporation experiments demonstrate that the Gli3, specifically Gli3R, is critical for specifying the fate of cortical neurons that are generated following a stereotypical temporal order. Moreover, Gli3 is required for maintaining the cortical progenitors in active cell cycle, suggesting that cells may acquire differentiated status as they turn off Gli3 expression during neurogenesis.

Increased proximal bifurcation of CA1 pyramidal apical dendrites in sema3A mutant mice.

Semaphorin-3A (Sema3A) is an attractive guidance molecule for cortical apical dendrites. To elucidate the role of Sema3A in hippocampal dendritic formation, we examined the Sema3A expression pattern in the perinatal hippocampal formation and analyzed hippocampal dendrites of the brains from young adult sema3A mutant mice. Sema3A protein was predominantly expressed in the hippocampal plate and the inner marginal zone at the initial period of apical dendritic growth. Neuropilin-1 and plexin-A, the receptor components for Sema3A, were also localized in the same regions. The Golgi impregnation method revealed that in wildtype mice more than 90% of hippocampal CA1 pyramidal neurons extended a single trunk or apical trunks bifurcated in stratum radiatum. Seven percent of the pyramidal neurons showed proximal bifurcation of apical trunks in stratum pyramidale or at the border of the stratum pyramidale and stratum radiatum. In sema3A mutant mice, proximally bifurcated apical dendrites were increased to 32%, while the single apical dendritic pyramidal neurons were decreased. We designate this phenotype in sema3A mutant mice as "proximal bifurcation." In the dissociated culture system, approximately half of the hippocampal neurons from wildtype mice resembled pyramidal neurons, which possess a long, thick, and tapered dendrite. In contrast, only 30% of the neurons from sema3A mutants exhibited pyramidal-like morphology. Proximal bifurcation of CA1 pyramidal neurons was also increased in the mutant mice of p35, an activator of cyclin-dependent kinase 5 (Cdk5). Thus, Sema3A may facilitate the initial growth of CA1 apical dendrites via the activation of p35/Cdk5, which may in turn signal hippocampal development.

Semaphorin3A signaling mediated by Fyn-dependent tyrosine phosphorylation of collapsin response mediator protein 2 at tyrosine 32.

Collapsin response mediator protein 2 (CRMP2) is an intracellular protein that mediates signaling of Semaphorin3A (Sema3A), a repulsive axon guidance molecule. Fyn, a Src-type tyrosine kinase, is involved in the Sema3A signaling. However, the relationship between CRMP2 and Fyn in this signaling pathway is still unknown. In our research, we demonstrated that Fyn phosphorylated CRMP2 at Tyr(32) residues in HEK293T cells. Immunohistochemical analysis using a phospho-specific antibody at Tyr(32) of CRMP showed that Tyr(32)-phosphorylated CRMP was abundant in the nervous system, including dorsal root ganglion neurons, the molecular and Purkinje cell layer of adult cerebellum, and hippocampal fimbria. Overexpression of a nonphosphorylated mutant (Tyr(32) to Phe(32)) of CRMP2 in dorsal root ganglion neurons interfered with Sema3A-induced growth cone collapse response. These results suggest that Fyn-dependent phosphorylation of CRMP2 at Tyr(32) is involved in Sema3A signaling.

Regulation of dendritic branching and spine maturation by semaphorin3A-Fyn signaling.

A member of semaphorin family, semaphorin3A (Sema3A), acts as a chemorepellent or chemoattractant on a wide variety of axons and dendrites in the development of the nervous systems. We here show that Sema3A induces clustering of both postsynaptic density-95 (PSD-95) and presynaptic synapsin I in cultured cortical neurons without changing the density of spines or filopodia. Neuropilin-1 (NRP-1), a receptor for Sema3A, is present on both axons and dendrites. When the cultured neurons are exposed to Sema3A, the cluster size of PSD-95 is markedly enhanced, and an extensive colocalization of PSD-95 and NRP-1 or actin-rich protrusion is seen. The effects of Sema3A on spine morphology are blocked by PP2, an Src type tyrosine kinase inhibitor, but not by the PP3, the inactive-related compound. In the cultured cortical neurons from fyn(-/-) mice, dendrites bear few spines, and Sema3A does not induce PSD-95 cluster formation on the dendrites. Sema3A and its receptor genes are highly expressed during the synaptogenic period of postnatal days 10 and 15. The cortical neurons in layer V, but not layer III, show a lowered density of synaptic bouton-like structure on dendrites in sema3A- and fyn-deficient mice. The neurons of the double-heterozygous mice show the lowered spine density, whereas those of single heterozygous mice show similar levels of the spine density as the wild type. These findings suggest that the Sema3A signaling pathway plays an important role in the regulation of dendritic spine maturation in the cerebral cortex neurons.

[The role of pharmacists for promotion of cancer chemotherapy in outpatients].

To promote cancer chemotherapy among outpatients, a special room for cancer chemotherapy (outpatient drip infusion room) was established in Yamaguchi University Hospital in April 2002. Since then, pharmacists have played a central role in all aspects, including decisions on the flow rate for prescriptions/injections, protocol checking, preparation of injections, aseptic preparation of anticancer agents, provision of information to patients, and financial impact analysis. In this study, we analyzed the current status of these activities and conducted a questionnaire survey regarding the involvement of pharmacists in chemotherapy at the outpatient clinic among patients and physicians. Pharmacists contributed to the administration of anticancer agents, including protocol checking and aseptic preparation, and no malpractice incident has occurred since the outpatient drip infusion room was established. According to responses from patients, 28 of 29 patients reported that they underwent treatment without anxiety. According to responses from physicians, 15 of 18 physicians considered the involvement of pharmacists beneficial. In addition, the amount claimed for health insurance as of March 2003 was 500000 yen, which was about 5-fold that before the establishment of the outpatient drip infusion room. These results suggest that pharmacists contribute to the promotion of cancer chemotherapy in outpatients with respect to the safety of medical practice, patient services, and hospital management. Therefore participation in cancer chemotherapy at the outpatient clinic may become a primary activity of pharmacists.

Fyn and Cdk5 mediate semaphorin-3A signaling, which is involved in regulation of dendrite orientation in cerebral cortex.

Semaphorin-3A (Sema3A), a member of class 3 semaphorins, regulates axon and dendrite guidance in the nervous system. How Sema3A and its receptors plexin-As and neuropilins regulate neuronal guidance is unknown. We observed that in fyn- and cdk5-deficient mice, Sema3A-induced growth cone collapse responses were attenuated compared to their heterologous controls. Cdk5 is associated with plexin-A2 through the active state of Fyn. Sema3A promotes Cdk5 activity through phosphorylation of Tyr15, a phosphorylation site with Fyn. A Cdk5 mutant (Tyr15 to Ala) shows a dominant-negative effect on the Sema3A-induced collapse response. The sema3A gene shows strong interaction with fyn for apical dendrite guidance in the cerebral cortex. We propose a signal transduction pathway in which Fyn and Cdk5 mediate neuronal guidance regulated by Sema3A.

[A checking system for injectable anticancer drugs using each patient's own data and its evaluation].

A checking system was developed for risk management of injectable anticancer drug use. Because the dosage and administration of injectable anticancer drugs vary with each patient, checking the prescription and aseptic i.v. admixing can be markedly complicated and time-consuming for pharmacists. The system we investigated in this study provided real-time checking of dosage, drip infusion rate, dosing periods, and dosing-free periods. The prescription parameters for this check included height, weight, body surface area, the medical history of each patient, the patient's ICD10 code' and disease indication from the package insert. Moreover, when preparing for aseptic i.v. admixing, the liquid volume after the anticancer drug has been mixed with other injectable drugs is calculated automatically. The time limits for stability after mixing and clinical laboratory test results are listed on the Work Sheet. As a result, 24 medication errors were prevented in the first 6 months of use of this system. These consisted of over- and under-doses, excessive dosing periods, insufficient dosing-free periods' etc. The time required for preparation of aseptic i.v. admixing decreased by 73% after introducing this system. Because clinical laboratory test results were referenced beforehand, patients to whom the drug should not be administered were recognized in advance. Thus 13 such cases were identified before i.v. admixing. Therefore this system may be useful in terms of rational anticancer drug use and risk management.