Mutation of the imprinted gene OsEMF2a induces autonomous endosperm development and delayed cellularization in rice.

In angiosperms, endosperm development comprises a series of developmental transitions controlled by genetic and epigenetic mechanisms that are initiated after double fertilization. Polycomb repressive complex 2 (PRC2) is a key component of these mechanisms that mediate histone H3 lysine 27 trimethylation (H3K27me3); the action of PRC2 is well described in Arabidopsis thaliana but remains uncertain in cereals. In this study, we demonstrate that mutation of the rice (Oryza sativa) gene EMBRYONIC FLOWER2a (OsEMF2a), encoding a zinc-finger containing component of PRC2, causes an autonomous endosperm phenotype involving proliferation of the central cell nuclei with separate cytoplasmic domains, even in the absence of fertilization. Detailed cytological and transcriptomic analyses revealed that the autonomous endosperm can produce storage compounds, starch granules, and protein bodies specific to the endosperm. These events have not been reported in Arabidopsis. After fertilization, we observed an abnormally delayed developmental transition in the endosperm. Transcriptome and H3K27me3 ChIP-seq analyses using endosperm from the emf2a mutant identified downstream targets of PRC2. These included >100 transcription factor genes such as type-I MADS-box genes, which are likely required for endosperm development. Our results demonstrate that OsEMF2a-containing PRC2 controls endosperm developmental programs before and after fertilization.

Root angle modifications by the DRO1 homolog improve rice yields in saline paddy fields.

The root system architecture (RSA) of crops can affect their production, particularly in abiotic stress conditions, such as with drought, waterlogging, and salinity. Salinity is a growing problem worldwide that negatively impacts on crop productivity, and it is believed that yields could be improved if RSAs that enabled plants to avoid saline conditions were identified. Here, we have demonstrated, through the cloning and characterization of qSOR1 (quantitative trait locus for SOIL SURFACE ROOTING 1), that a shallower root growth angle (RGA) could enhance rice yields in saline paddies. qSOR1 is negatively regulated by auxin, predominantly expressed in root columella cells, and involved in the gravitropic responses of roots. qSOR1 was found to be a homolog of DRO1 (DEEPER ROOTING 1), which is known to control RGA. CRISPR-Cas9 assays revealed that other DRO1 homologs were also involved in RGA. Introgression lines with combinations of gain-of-function and loss-of-function alleles in qSOR1 and DRO1 demonstrated four different RSAs (ultra-shallow, shallow, intermediate, and deep rooting), suggesting that natural alleles of the DRO1 homologs could be utilized to control RSA variations in rice. In saline paddies, near-isogenic lines carrying the qSOR1 loss-of-function allele had soil-surface roots (SOR) that enabled rice to avoid the reducing stresses of saline soils, resulting in increased yields compared to the parental cultivars without SOR. Our findings suggest that DRO1 homologs are valuable targets for RSA breeding and could lead to improved rice production in environments characterized by abiotic stress.

Current status and perspectives for endoscopic diagnosis of superficial nonampullary duodenal epithelial tumors.

In recent years, there have been significant advances in the endoscopic resection (ER) procedures of superficial nonampullary duodenal epithelial tumors (SNADETs). A preoperative endoscopic diagnosis is thus deemed necessary in determining the indication for subsequent ER. For the histologic and endoscopic diagnosis of SNADETs, understanding the mucin phenotype is inevitable. Recently, two diagnostic algorithms for the differential diagnosis of SNADETs from nonneoplastic lesions under magnifying endoscopy with narrow-band imaging have been proposed. In addition, various endoscopic approaches have been proposed to differentiate low- and high-grade adenomas/carcinomas, including white light endoscopy, magnifying image-enhanced endoscopy, and endocytoscopy. These methods, however, have not been standardized with respect to the classification of their findings and the validation of their diagnostic accuracy. Moreover, there are still concerns with respect to the histologic criteria required to establish a SNADETs diagnosis. Standardization in the histologic and endoscopic diagnosis of SNADETs is needed.

Regulation of germination by targeted mutagenesis of grain dormancy genes in barley.

High humidity during harvest season often causes pre-harvest sprouting in barley (Hordeum vulgare). Prolonged grain dormancy prevents pre-harvest sprouting; however, extended dormancy can interfere with malt production and uniform germination upon sowing. In this study, we used Cas9-induced targeted mutagenesis to create single and double mutants in QTL FOR SEED DORMANCY 1 (Qsd1) and Qsd2 in the same genetic background. We performed germination assays in independent qsd1 and qsd2 single mutants, as well as in two double mutants, which revealed a strong repression of germination in the mutants. These results demonstrated that normal early grain germination requires both Qsd1 and Qsd2 function. However, germination of qsd1 was promoted by treatment with 3% hydrogen peroxide, supporting the notion that the mutants exhibit delayed germination. Likewise, exposure to cold temperatures largely alleviated the block of germination in the single and double mutants. Notably, qsd1 mutants partially suppress the long dormancy phenotype of qsd2, while qsd2 mutant grains failed to germinate in the light, but not in the dark. Consistent with the delay in germination, abscisic acid accumulated in all mutants relative to the wild type, but abscisic acid levels cannot maintain long-term dormancy and only delay germination. Elucidation of mutant allele interactions, such as those shown in this study, are important for fine-tuning traits that will lead to the design of grain dormancy through combinations of mutant alleles. Thus, these mutants will provide the necessary germplasm to study grain dormancy and germination in barley.

GWAS with principal component analysis identifies a gene comprehensively controlling rice architecture.

Elucidation of the genetic control of rice architecture is crucial due to the global demand for high crop yields. Rice architecture is a complex trait affected by plant height, tillering, and panicle morphology. In this study, principal component analysis (PCA) on 8 typical traits related to plant architecture revealed that the first principal component (PC), PC1, provided the most information on traits that determine rice architecture. A genome-wide association study (GWAS) using PC1 as a dependent variable was used to isolate a gene encoding rice, SPINDLY (OsSPY), that activates the gibberellin (GA) signal suppression protein SLR1. The effect of GA signaling on the regulation of rice architecture was confirmed in 9 types of isogenic plant having different levels of GA responsiveness. Further population genetics analysis demonstrated that the functional allele of OsSPY associated with semidwarfism and small panicles was selected in the process of rice breeding. In summary, the use of PCA in GWAS will aid in uncovering genes involved in traits with complex characteristics.

Precision genome editing in plants via gene targeting and subsequent break-induced single-strand annealing.

Genome editing via artificial nucleases such as CRISPR/Cas9 has become popular in plants now. However, small insertions or deletions are major mutations and nucleotide substitutions rarely occur when DNA cleavage is induced. To induce nucleotide substitutions, a base editor utilizing dead or nickase-type Cas9 fused with deaminase have been developed. However, the direction and position of practical substitution are still limited. In this context, homologous recombination (HR)-mediated gene targeting (GT) has advantages because any mutations existing on the donor DNA are copied and passed onto the endogenous DNA. As HR-mediated GT is extremely rare in higher plants, positive-negative selection has been used to isolate cells in which GT has occurred. After successful selection, positive selection marker is no longer needed and should ideally be eliminated. In a previous study, we reported a seamless piggyBac-transposon-mediated marker elimination system. Precision marker elimination efficiency in this system is very high. The piggyBac transposon integrates into the host genome at TTAA elements and excises without leaving a footprint at the excised site, so a TTAA sequence is necessary at the location of a positive selection marker. To compensate for this limitation, we have developed a novel marker elimination system using an I-SceI break and subsequent single-strand annealing (SSA)-mediated DNA repair system.

Allelic Mutations in the Ripening -Inhibitor Locus Generate Extensive Variation in Tomato Ripening.

RIPENING INHIBITOR (RIN) is a transcription factor with transcriptional activator activity that plays a major role in regulating fruit ripening in tomato (Solanum lycopersicum). Recent studies have revealed that (1) RIN is indispensable for full ripening but not for the induction of ripening; and (2) the rin mutation, which produces nonripening fruits that never turn red or soften, is not a null mutation but instead converts the encoded transcriptional activator into a repressor. Here, we have uncovered aspects of RIN function by characterizing a series of allelic mutations within this locus that were produced by CRISPR/Cas9. Fruits of RIN-knockout plants, which are characterized by partial ripening and low levels of lycopene but never turn fully red, showed excess flesh softening compared to the wild type. The knockout mutant fruits also showed accelerated cell wall degradation, suggesting that, contrary to the conventional view, RIN represses over-ripening in addition to facilitating ripening. A C-terminal domain-truncated RIN protein, encoded by another allele of the RIN locus (rinG2), did not activate transcription but formed transcription factor complexes that bound to target genomic regions in a manner similar to that observed for wild-type RIN protein. Fruits expressing this truncated RIN protein exhibited extended shelf life, but unlike rin fruits, they accumulated lycopene and appeared orange. The diverse ripening properties of the RIN allelic mutants suggest that substantial phenotypic variation can be produced by tuning the activity of a transcription factor.

Site-directed mutagenesis by biolistic transformation efficiently generates inheritable mutations in a targeted locus in soybean somatic embryos and transgene-free descendants in the T1 generation.

The clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated endonuclease 9 (Cas9) system is being rapidly developed for mutagenesis in higher plants. Ideally, foreign DNA introduced by this system is removed in the breeding of edible crops and vegetables. Here, we report an efficient generation of Cas9-free mutants lacking an allergenic gene, Gly m Bd 30K, using biolistic transformation and the CRISPR/Cas9 system. Five transgenic embryo lines were selected on the basis of hygromycin resistance. Cleaved amplified polymorphic sequence analysis detected only two different mutations in e all of the lines. These results indicate that mutations were induced in the target gene immediately after the delivery of the exogenous gene into the embryo cells. Soybean plantlets (T0 plants) were regenerated from two of the transgenic embryo lines. The segregation pattern of the Cas9 gene in the T1 generation, which included Cas9-free plants, revealed that a single copy number of transgene was integrated in both lines. Immunoblot analysis demonstrated that no Gly m Bd 30K protein accumulated in the Cas9-free plants. Gene expression analysis indicated that nonsense mRNA decay might have occurred in mature mutant seeds. Due to the efficient induction of inheritable mutations and the low integrated transgene copy number in the T0 plants, we could remove foreign DNA easily by genetic segregation in the T1 generation. Our results demonstrate that biolistic transformation of soybean embryos is useful for CRISPR/Cas9-mediated site-directed mutagenesis of soybean for human consumption.

Protective effect of proton pump inhibitors and potassium competitive acid blockers against post-gastric endoscopic submucosal dissection bleeding: a single-center, propensity score-matched analysis.

OBJECTIVES: Both potassium-competitive acid blockers (P-CABs) and proton pump inhibitors (PPIs) are known to be protective against bleeding after gastric endoscopic dissection (ESD) for early gastric cancers. The aim was to compare the effect of PPI and P-CAB treatment against bleeding after gastric ESD. MATERIALS AND METHODS: This was a single-center, retrospective analysis. Among 541 patients who underwent gastric ESD during the period from 2014 to 2019, we recruited subjects who were treated with PPIs (intravenous lansoprazole followed by oral esomeprazole) or a P-CAB before and after ESD. The incidence of post-ESD bleeding was compared between treatment groups. The risks associated with post-ESD bleeding were examined by univariate and multivariate analyses after propensity score-matching. RESULTS: The overall incidence of post-ESD bleeding was not significantly different between patients treated with PPIs (n = 362) and those treated with a P-CAB (n = 156) (3.0% vs 2.6%, respectively; p = .77). Even after propensity score matching (n = 153 in each group), the incidence was not significantly different between groups (2.6% vs 2.6%, respectively; p = 1.00). A multivariate analysis revealed that antithrombotic therapy (OR 4.85, 95% CI 1.14-20.57) was an independent factor associated with post-ESD bleeding. CONCLUSIONS: The incidence of post gastric ESD bleeding is not different between patients treated with PPI and patients treated with P-CAB. Antithrombotic therapy is an independent risk factor associated with post-ESD bleeding.

Prognostic nutritional index is an independent prognostic factor for older patients aged ≥ 85 years treated by gastric endoscopic submucosal dissection.

BACKGROUND: Clinical outcomes and prognostic factors for survival after endoscopic submucosal dissection (ESD) in older patients aged ≥ 85 years with early gastric cancer (EGC) are not well defined. The aim of this study was to investigate the clinical outcomes and prognostic factors for survival after ESD in older patients aged ≥ 85 years with EGC. METHODS: Clinical outcomes of 70 patients aged ≥ 85 years with EGC treated with ESD were evaluated retrospectively. Prognostic factors for overall survival (OS) were analyzed with the Kaplan-Meier method and a Cox proportional hazards model. RESULTS: During the follow-up period, 33 patients died from any cause, none of whom died from gastric cancer. OS probability after 3 years was 90.0%. Univariate analyses revealed that a neutrophil/lymphocyte ratio ≥ 2.6, a prognostic nutritional index (PNI) < 42.5 and low serum albumin value (< 3.5 g/dl) were associated with poor OS. Cox multivariate analysis revealed low PNI (< 42.5) to be an independent prognostic factor associated with OS (hazard ratio; 3.40, 95% confidence interval; 1.47-7.86, P = 0.004). CONCLUSIONS: PNI may be a useful parameter for making the decision to perform ESD for older patients aged ≥ 85 years with EGC.

Resectability of underwater endoscopic mucosal resection for duodenal tumor: A single-center, retrospective pilot study.

BACKGROUND AND AIM: Underwater endoscopic mucosal resection (U-EMR) has been attracting much attention as treatment for patients with nonampullary duodenal epithelial tumors (NADETs). We aim to compare treatment outcomes, including submucosal resectability, between patients undergoing U-EMR and conventional endoscopic mucosal resection (C-EMR) for NADET. METHODS: We conducted a retrospective review of 38 patients with NADET treated by U-EMR or C-EMR. In the resected specimens, we measured the horizontal length, the vertical distance from the muscularis mucosa to the margin at the deepest site, and the overall submucosal area. The submucosal index (SMI) was defined as the overall submucosal area divided by the largest horizontal length. These values and other treatment outcomes were compared between NADETs resected by U-EMR and C-EMR. RESULTS: The median size of lesions was 7 mm with a range of 3-13 mm. Although the incidence of adverse events and the rates of en bloc and R0 resection were not different in the two groups, the median procedure time was significantly shorter in the U-EMR group (11 min vs 13 min; P = 0.045). The median submucosal depth at the deepest site (1.22 mm vs 1.08 mm; P = 0.38) and the median SMI (0.44 vs 0.41; P = 0.42) were not different between groups. CONCLUSIONS: The resectability between NADETs treated by U-EMR and C-EMR was comparable. These results, together with the shorter procedure time required for U-EMR, suggest that U-EMR may have the potential to be the first choice for small to medium-sized NADET.

Immunohistochemical Analysis of Mismatch Repair Gene Proteins in Early Gastric Cancer Based on Microsatellite Status.

BACKGROUND: Microsatellite instability (MSI) is a major pathway involved in gastric carcinogenesis and is observed in 10-20% of early gastric cancers (EGCs). Early detection of EGCs with an MSI-high phenotype would be useful for elucidating the mechanisms of gastric carcinogenesis and improving outcomes in patients with GC. OBJECTIVE: We explored the usefulness of immunohistochemical expression of mismatch repair (MMR) proteins, including MLH1, PMS2, MSH2, and MSH6 in EGC. METHODS: We examined the expression of 4 MMR proteins using immunohistochemistry in 119 patients with EGC based on MS status, as determined by polymerase chain reaction-microsatellite analysis. In addition, methylation of the MLH1 gene was quantified by pyrosequencing. RESULTS: EGCs were classified into 46 MSI-high phenotypes and 73 microsatellite stable (MSS) phenotypes. Although loss of MLH1 expression was associated with loss of PMS2 expression in the MSI-high phenotype, discordant cases of loss of expression between MLH1 and PMS2 were found (MLH1 [-]/PMS2 [+], 3 cases). Loss of MLH1/PMS2 expression was observed in 2 of 73 MSS phenotypes. Loss of MSH2/MSH6 expression was found in 4 of 46 MSI-high phenotypes, whereas loss of MSH2/MSH6 expression was not detected in the MSS phenotype. In addition, loss of MLH1 expression was correlated with methylation of MLH1. However, there were discordant cases in which loss of MLH1 expression was not accompanied by methylation of MLH1. CONCLUSION: Although immunostaining of MMR proteins could help predict MSI in EGCs, immunostaining did not have the same value as genetic testing for determination of MSI.

Risk for lymph node metastasis in Epstein-Barr virus-associated gastric carcinoma with submucosal invasion.

OBJECTIVES: Epstein-Barr virus-associated gastric cancer (EBVGC) has been reported to be associated with a low risk for lymph node metastasis (LNM). However, the curative criteria for endoscopic submucosal dissection (ESD) for submucosal EBVGC (pT1b-EBVGC) remain unclear. Our study aimed to investigate the risk factors for LNM in pT1b-EBVGC. METHODS: This was a retrospective multicenter study at five institutes in Japan. We reviewed medical records and extracted all pT1b-EBVGC cases that met the following criteria: (i) histologically proven submucosal gastric cancer; (ii) surgical or endoscopic resection between January 2000 and December 2016; and (iii) presence of Epstein-Barr virus (EBV) in tumor cells verified by EBV-encoded small RNA in situ hybridization (EBER-ISH). The association between clinicopathological factors and LNM were assessed using multivariable logistic regression analysis. RESULTS: A total of 185 pT1b-EBVGC cases were included in the analysis. LNM was found in nine cases (4.9%). Multivariable logistic regression analysis demonstrated that lymphatic invasion (OR 9.1; 95% CI 2.1-46.1) and submucosal invasion ≥4000 µm (OR 9.2; 95% CI 1.3-110.3) were significant risk factors for LNM. When we focused on pT1b-EBVGC without lymphatic invasion and with submucosal invasion <2000 µm, the rate of LNM was 0% (0/96, 95% CI 0-3.8%). CONCLUSIONS: Our findings indicated that lymphatic invasion and submucosal invasion ≥4000 µm were significant risk factors for LNM. ESD could be an appropriate option for pT1b-EBVGC without lymphatic invasion and with submucosal invasion <2000 µm.

Simultaneous induction of mutant alleles of two allergenic genes in soybean by using site-directed mutagenesis.

BACKGROUND: Soybean (Glycine max) is a major protein crop, because soybean protein has an amino acid score comparable to that of beef and egg white. However, many allergens have been identified among soybean proteins. A decrease in allergenic protein levels would be useful for expanding the market for soybean proteins and processed foods. Recently, the CRISPR/Cas9 system has been adopted as a powerful tool for the site-directed mutagenesis in higher plants. This system is expected to generate hypoallergenic soybean varieties. RESULTS: We used two guide RNAs (gRNAs) and Agrobacterium-mediated transformation for simultaneous site-directed mutagenesis of two genes encoding the major allergens Gly m Bd 28 K and Gly m Bd 30 K in two Japanese soybean varieties, Enrei and Kariyutaka. We obtained two independent T0 Enrei plants and nine T0 Kariyutaka plants. Cleaved amplified polymorphic sequence (CAPS) analysis revealed that mutations were induced in both targeted loci of both soybean varieties. Sequencing analysis showed that deletions were the predominant mutation type in the targeted loci. The Cas9-free plants carrying the mutant alleles of the targeted loci with the transgenes excluded by genetic segregation were obtained in the T2 and T3 generations. Variable mutational spectra were observed in the targeted loci even in T2 and T3 progenies of the same T0 plant. Induction of multiple mutant alleles resulted in six haplotypes in the Cas9-free mutants derived from one T0 plant. Immunoblot analysis revealed that no Gly m Bd 28 K or Gly m Bd 30 K protein accumulated in the seeds of the Cas9-free plants. Whole-genome sequencing confirmed that a Cas9-free mutant had also no the other foreign DNA from the binary vector. Our results demonstrate the applicability of the CRISPR/Cas9 system for the production of hypoallergenic soybean plants. CONCLUSIONS: Simultaneous site-directed mutagenesis by the CRISPR/Cas9 system removed two major allergenic proteins from mature soybean seeds. This system enables rapid and efficient modification of seed components in soybean varieties.

Risk Factors for Post-gastric Endoscopic Submucosal Dissection Bleeding with a Special Emphasis on Anticoagulant Therapy.

BACKGROUND: Little is known about the risk factors for post endoscopic submucosal dissection (post-ESD) bleeding with anticoagulant therapy. AIMS: We aimed to investigate the risk factors for post-ESD bleeding for early gastric cancer (EGC) with an emphasis on anticoagulant therapy. METHODS: We retrospectively analyzed 2355 EGCs, including 137 lesions in patients treated under anticoagulants. Clinicopathological findings were evaluated between lesions in patients with and without anticoagulant therapy with propensity score matching analysis. The factors associated with post-ESD bleeding were analyzed with multivariate analysis with a logistic regression method. RESULTS: After propensity score matching, post-ESD bleeding was significantly more frequent in lesions of patients with than without anticoagulant therapy (11.7% vs 1.5%, respectively; P = 0.001). A univariate analysis revealed that anticoagulant therapy, heparin bridge therapy, undifferentiated type, deep submucosal invasion, and resected specimen size were associated with post-ESD bleeding. A multivariate analysis revealed anticoagulant therapy (OR 23.1, 95% CI 3.61-147.52) and resected specimen size (OR 1.03, 95% CI 1.00-1.06) to be independent factors associated with post-ESD bleeding. CONCLUSIONS: Anticoagulant therapy and resected specimen size were risk factors associated with post-ESD bleeding for EGC.

Diagnostic algorithm of magnifying endoscopy with crystal violet staining for non-ampullary duodenal epithelial tumors.

OBJECTIVES: Little is known about the usefulness of magnifying endoscopy with crystal violet staining (ME-CV) for the diagnosis of duodenal tumors. We assessed the ability of ME-CV to distinguish Vienna classification (VCL) category 4/5 (C4/5) from category 3 (C3) non-ampullary duodenal epithelial tumors (NADETs). METHODS: A total of 76 NADETs were studied. We retrospectively analyzed the diagnostic values of the white light endoscopy (WLE) scoring system and the ME-CV algorithm with receiver operating characteristic (ROC) curves, and three endoscopists calculated the sensitivity, specificity, accuracy, and the area under the curve (AUC) of each. The diagnostic values were tested among NADETs overall and among subgroups of tumors with gastric, gastrointestinal or intestinal mucin phenotypes. Inter-observer agreement of the diagnostic results was also calculated. RESULTS: According to the VCL, 54 lesions (71.1%) were regarded as C3 and 22 lesions (28.9%) as C4/5. The sensitivity, specificity, accuracy and AUC of ME-CV were higher than those of the WLE scoring system (63.6 vs 54.5, 85.2 vs 75.9, 78.9 vs 69.7, 0.744 vs 0.652, respectively). Inter-observer agreements of the WLE scoring system and ME-CV were both moderate (kappa 0.45 and 0.41). ME-CV had higher sensitivity, specificity, accuracy and AUC than those of the WLE scoring system among the gastric and intestinal phenotypes of NADETs. CONCLUSIONS: ME-CV is appropriate for the diagnosis of C4/5 and C3 NADETs.

CYP81A P450s are involved in concomitant cross-resistance to acetolactate synthase and acetyl-CoA carboxylase herbicides in Echinochloa phyllopogon.

Californian populations of Echinochloa phyllopogon have evolved multiple-herbicide resistance (MHR), posing a threat to rice production in California. Previously, we identified two CYP81A cytochrome P450 genes whose overexpression is associated with resistance to acetolactate synthase (ALS) inhibitors from two chemical groups. Resistance mechanisms to other herbicides remain unknown. We analyzed the sensitivity of an MHR line to acetyl-CoA carboxylase (ACCase) inhibitors from three chemical groups, followed by an analysis of herbicide metabolism and segregation of resistance of the progenies in sensitive (S) and MHR lines. ACCase herbicide metabolizing function was investigated in the two previously identified P450s. MHR plants exhibited resistance to all the ACCase inhibitors by enhanced herbicide metabolism. Resistance to the ACCase inhibitors segregated in a 3 : 1 ratio in the F2 generation and completely co-segregated with ALS inhibitor resistance in F6 lines. Expression of the respective P450 genes conferred resistance to the three herbicides in rice, which is in line with the detection of hydroxylated herbicide metabolites in vivo in transformed yeast. CYP81As are super P450s that metabolize multiple herbicides from five chemical classes, and concurrent overexpression of the P450s induces metabolism-based resistance to the three ACCase inhibitors in MHR E. phyllopogon, as it does to ALS inhibitors.

Long-term outcomes and prognostic factors with non-curative endoscopic submucosal dissection for gastric cancer in elderly patients aged ≥ 75 years.

BACKGROUND: Little is known about the long-term outcomes and prognostic factors with non-curative endoscopic submucosal dissection (ESD) in elderly patients with early gastric cancer. METHODS: Clinicopathological findings and long-term outcomes were evaluated in 87 patients with early gastric cancer (EGC) aged ≥ 75 years who were treated with non-curative ESD. Prognostic factors for overall survival (OS) were analyzed with the Kaplan-Meier method and a Cox proportional hazards model. RESULTS: During the follow-up period, among 27 patients who died of any cause, only one patient died of gastric cancer. OS probabilities after 3 and 5 years were 89.7% and 79.3%, respectively. Univariate analyses revealed that Eastern Cooperative Oncology Group performance status 2-3, Charlson comorbidity index (CCI) ≥ 3, neutrophil/lymphocyte ratio ≥ 3.3, prognostic nutritional index < 44.8, distal tumor location and macroscopically depressed or flat configuration were associated with poor OS. Cox multivariate analysis revealed high CCI (≥ 3) to be an independent prognostic factor associated with OS (hazard ratio: 2.63, 95% confidence interval [CI] 1.06-6.49, P = 0.037). CONCLUSIONS: CCI may be a useful parameter for decision-making regarding additional surgery for elderly patients with gastric cancer treated by non-curative ESD.

Targeted deletion of rice retrotransposon Tos17 via CRISPR/Cas9.

KEY MESSAGE: A successful example of transposon deletion via CRISPR/Cas9-mediated genome editing suggests a novel alternative approach to plant breeding. Transposition of transposable elements (TEs) can affect adjacent genes, leading to changes in genetic traits. Expression levels and patterns, splicing and epigenetic status, and function of genes located in, or near, the inserted/excised locus can be affected. Artificial modification of loci adjacent to TEs, or TEs themselves, by genome editing could mimic the translocation of TEs that occurs in nature, suggesting that it might be possible to produce novel plants by modification of TEs via genome editing. To our knowledge, there are no reports thus far of modification of TEs by genome editing in plants. In this study, we performed targeted deletion of the Tos17 retrotransposon, which is flanked at both ends by long terminal repeat (LTR) sequences, via genome editing in rice. We succeeded in targeted mutagenesis of the LTR, and targeted deletion between LTRs, in calli transformed with CRISPR/Cas9 vectors for the Tos17 LTR. Moreover, we also successfully obtained regenerated plants derived from transformed calli and plants homozygous for lacking Tos17 in the next generation. Taken together, our results demonstrate successful deletion of the Tos17 retrotransposon from the rice genome by targeted mutagenesis using CRISPR/Cas9. We believe that this strategy could be applied to other TEs in many plant species, providing a rapid breeding technology as an alternative means to re-activate expression of agronomically important genes that have been inactivated by TE insertion, especially in plants such as fruit trees, in which it is difficult to maintain parental agronomical traits by cross-breeding due to high heterozygosity.

Short-term outcomes of multicenter prospective cohort study of gastric endoscopic resection: 'Real-world evidence' in Japan.

OBJECTIVES: A Japanese multicenter prospective cohort study examining endoscopic resection (ER) for early gastric cancer (EGC) has been conducted using a Web registry developed to determine the short-term and long-term outcomes based on absolute and expanded indications. We hereby present the short-term outcomes of this study. METHODS: All consecutive patients with EGC or suspected EGC undergoing ER at 41 participating institutions between July 2010 and June 2012 were enrolled and prospectively registered into the Web registry. The baseline characteristics were entered before ER, and the short-term outcomes were collected at 6 months following ER. RESULTS: Nine thousand six hundred and sixteen patients with 10 821 lesions underwent ER (endoscopic submucosal dissection [ESD]: 99.4%). The median procedure time was 76 min, and R0 resections were achieved for 91.6% of the lesions. Postoperative bleeding and intraoperative perforation occurred in 4.4% and 2.3% of the patients, respectively. Significant independent factors correlated with a longer procedure time (120 min or longer) were as follows: tumor size >20 mm, upper-third location, middle-third location, local recurrent lesion, ulcer findings, gastric tube, male gender, and submucosa. Histopathologically, 10 031 lesions were identified as common-type gastric cancers. The median tumor size was 15 mm. Noncurative resections were diagnosed for 18.3% of the lesions. Additional surgery was performed for 48.6% (824 lesions) of the 1695 noncurative ER lesions with a possible risk of lymph node (LN) metastasis. Among them, 64 (7.8%) exhibited LN metastasis. CONCLUSIONS: This multicenter prospective study showed favorable short-term outcomes for gastric ESD.