Outcomes of laparoscopic and endoscopic cooperative surgery for gastric submucosal tumors: A retrospective multicenter study at 21 Japanese institutions.

Aim: We conducted a multicenter study on classical laparoscopic and endoscopic cooperative surgery (LECS) and LECS-related procedures to retrospectively clarify the safety, problems, and mid-term outcomes of these methods after their coverage by the national health insurance. Methods: A total of 201 patients who underwent classical LECS/LECS-related procedures for gastric submucosal tumors (G-SMTs) in 21 institutions affiliated with the Laparoscopy Endoscopy Cooperative Surgery Study Group from April 2014 to March 2016 were included. Data was retrospectively obtained from the patients' charts. Results: The most common surgical procedure was classical LECS (155 patients, 77.1%), non-exposed endoscopic wall inversion surgery (22 patients, 11.4%), a combination of laparoscopic and endoscopic approaches to neoplasia with non-exposure technique (16 patients, 8%), and closed LECS (two patients, 1%). Only six (3%) patients underwent LECS with gastrostomy. The mean operative time and blood loss were 188.4 (70-462) minutes and 23.3 (0-793) g, respectively. Ten (5%) patients developed postoperative complications (Clavien-Dindo classification grade II or higher). Two patients needed reoperation due to postoperative bleeding or anastomotic leakage. All tumors were resected with negative margins. A total of 127 (63.2%) patients underwent follow-up observations for over 36 months, one of whom had a recurrence of peritoneal dissemination and one had poor oral intake. Conclusion: Classical LECS and LECS-related procedures for G-SMTs have favorable short/mid-term outcomes.

Extrahepatic Portal Venous Gas Is the Strongest Predictor of Mortality in Patients with Portal Venous Gas and Pneumatosis Intestinalis.

BACKGROUND: Very few studies have examined the association between contrast-enhanced computed tomography (CT) findings observed in portal venous gas (PVG) and pneumatosis intestinalis (PI) and the underlying diseases in these conditions. OBJECTIVES: In this study, we analyzed this association and report the findings for predicting mortality. MATERIALS AND METHODS: Overall, 50 patients diagnosed with PVG or PI, observed on contrast-enhanced CT, underwent treatment at our hospital. Based on the underlying disease, we divided the patients into three groups, those with ischemic disease, infectious disease, or gastrointestinal dilatation. Furthermore, cases that underwent surgical treatment or needed surgery but were inoperable were assigned to the high risk group (n=16) and patients who received conservative treatment were assigned to the low risk group (n=34). We reviewed the patients' medical charts, laboratory data, and CT images retrospectively, and analyzed the relationship between CT findings, underlying disease, and association with the high risk or low risk group in each case. RESULTS: Poor enhancement of the intestinal wall, mesenteric fat stranding, extrahepatic PVG, advanced age, and renal disease were significantly associated with ischemic disease (p=0.02, p=0.02, p=0.005, p=0.008 and p=0.049, respectively). PI alone was strongly associated with gastrointestinal dilatation (p=0.009). Patients in the low risk group had more favorable outcomes with conservative treatment. In multivariate analysis, extrahepatic PVG was the only factor associated with the high risk group (p=0.002). CONCLUSION: Extrahepatic PVG associated with ischemic disease was the strongest predictive factor of mortality. Other CT findings, though useful in diagnosing the underlying disease, were not significant predictive factors.

Identification of DNA Repair-related Genes as Biomarkers Reflecting MSI, TMB, and TIL in Colorectal Cancer.

BACKGROUND/AIM: There are no established biomarkers for immune checkpoint inhibitors (ICI) in colorectal cancer (CRC) with microsatellite stability (MSS) or proficient mismatch repair (pMMR). Therefore, this study aimed to identify biomarkers for ICI benefit in patients with pMMR by analyzing the down-regulated DNA repair-related genes involved in highly immunogenic and immune responses, and comparing their expression levels and clinical features. MATERIALS AND METHODS: Mismatch repair (MMR), tumor-infiltrating lymphocytes (TIL), and tumor mutation burden (TMB) were evaluated in 13 CRC cases and mRNA expression levels of 95 DNA repair-related genes were measured. DNA repair-related genes with reduced mRNA expression in the high immunogenicity and high immune response groups were identified. Then, the mRNA expression levels of the identified DNA repair-related genes were measured in 135 patients with CRC. Hierarchical cluster analysis was performed using the mRNA expression levels to compare the clinicopathological characteristics of each cluster. RESULTS: ATR, LIG4, and RAD52 mRNA levels were significantly down-regulated in the high immunogenicity group. GADD45B, SMUG1, and XRCC6 mRNA levels were significantly down-regulated in the high immune response group. Cases in the cluster with reduced mRNA expression of the six genes were pMMR cases. CD8 mRNA expression level was higher in this cluster than in the other clusters. CONCLUSION: Decreased mRNA expression levels of ATR, LIG4, RAD52, GADD45B, SMUG1, and XRCC6 genes were associated with high cytotoxic T cell and TMB levels, suggesting that these genes could serve as biomarkers for ICI efficacy in pMMR cases.

Guanylate binding protein 5 is an immune-related biomarker of oral squamous cell carcinoma: A retrospective prognostic study with bioinformatic analysis.

BACKGROUND: Cancer utilizes immunosuppressive mechanisms to create a tumor microenvironment favorable for its progression. The purpose of this study is to histologically characterize the immunological properties of the tumor microenvironment of oral squamous cell carcinoma (OSCC) and identify key molecules involved in the immunological microenvironment and patient prognosis. METHODS: First, overlapping differentially expressed genes (DEGs) were screened from OSCC transcriptome data in public databases. Correlation analysis of DEGs with known immune-related genes identified genes involved in the immune microenvironment of OSCC. Next, stromal patterns of tumor were classified and immunohistochemical staining was performed for immune cell markers (CD3, CD4, Foxp3, CD8, CD20, CD68, and CD163), programmed death-ligand 1 (PD-L1), and guanylate binding protein 5 (GBP5) in resected specimens obtained from 110 patients with OSCC who underwent resection. Correlations between each factor and their prognostic impact were analyzed. RESULTS: Among the novel OSCC-specific immune-related genes screened (including ADAMDEC1, CXCL9, CXCL13, DPT, GBP5, IDO1, and PLA2G7), GBP5 was selected as the target gene. Histopathologic analysis showed that multiple T-cell subsets and CD20-positive cells were less common in the advanced stages, whereas CD163-positive cells were more common in advanced stages. The immature type in the stromal pattern category was associated with less immune cell infiltration, lower expression of PD-L1 in immune cells, lower expression of GBP5 in the stroma, and shorter overall survival and recurrence-free survival. Expression of GBP5 in the tumor and stroma correlated with immune cell infiltration of tumors and PD-L1 expression in tumor and immune cells. Patients with low tumor GBP5 expression and high stromal expression had significantly longer overall survival and recurrence-free survival. CONCLUSIONS: The stromal pattern category may reflect both invasive and immunomodulatory potentials of cancer-associated fibroblasts in OSCC. GBP5 has been suggested as a potential biomarker to predict the prognosis and therapeutic efficacy of immune checkpoint inhibitors.

Comparison of Effective Imaging Modalities for Detecting Gastric Neoplasms: A Randomized 3-Arm Phase II Trial.

INTRODUCTION: The early detection of gastric neoplasms (GNs) leads to favorable treatment outcomes. The latest endoscopic system, EVIS X1, includes third-generation narrow-band imaging (3G-NBI), texture and color enhancement imaging (TXI), and high-definition white-light imaging (WLI). Therefore, this randomized phase II trial aimed to identify the most promising imaging modality for GN detection using 3G-NBI and TXI. METHODS: Patients with scheduled surveillance endoscopy after a history of esophageal cancer or GN or preoperative endoscopy for known esophageal cancer or GN were randomly assigned to the 3G-NBI, TXI, or WLI groups. Endoscopic observations were performed to detect new GN lesions, and all suspected lesions were biopsied. The primary endpoint was the GN detection rate during primary observation. Secondary endpoints were the rate of missed GNs, early gastric cancer detection rate, and positive predictive value for a GN diagnosis. The decision rule had a higher GN detection rate between 3G-NBI and TXI, outperforming WLI by >1.0%. RESULTS: Finally, 901 patients were enrolled and assigned to the 3G-NBI, TXI, and WLI groups (300, 300, and 301 patients, respectively). GN detection rates in the 3G-NBI, TXI, and WLI groups were 7.3, 5.0, and 5.6%, respectively. The rates of missed GNs were 1.0, 0.7, and 1.0%, the detection rates of early gastric cancer were 5.7, 4.0, and 5.6%, and the positive predictive values for the diagnosis of GN were 36.5, 21.3, and 36.8% in the 3G-NBI, TXI, and WLI groups, respectively. DISCUSSION: Compared with TXI and WLI, 3G-NBI is a more promising modality for GN detection.

Laparoscopic transabdominal approach for resection of presacral epidermoid cyst in an obese man: a case report.

BACKGROUND: Complete resection of presacral epidermoid cysts is recommended due to the potential for infection or malignancy. Transsacral and transabdominal approaches have been used to treat presacral tumors. However, there are no standard surgical approaches to resection. We present the case of a presacral epidermoid cyst in an obese male patient who underwent laparoscopic transabdominal resection. CASE PRESENTATION: A 44-year-old man was referred to our hospital for treatment of a cystic tumor on the pelvic floor. Contrast-enhanced computed tomography revealed a 45 × 40-mm tumor on the left ventral side of the rectum, right side of the ischial spine, dorsal side of the seminal vesicles, and in front of the 5th sacrum. Enhanced magnetic resonance imaging revealed a multilocular cystic tumor with high and low signal intensities on T2-weighted images. The tumor was diagnosed as an epidermoid cyst. We considered the transsacral or laparoscopic approach and decided to perform a laparoscopic-assisted transabdominal resection since the tumor was in front of away from the sacrum, and a transsacral approach would result in a larger scar due to poor visibility from the thickness of the buttocks. The entire tumor was safely resected under laparoscopic guidance, because the laparoscopic transabdominal approach can provide a good and magnified field of view even in a narrow pelvic cavity with small skin incisions, allowing safe resection of the pelvic organs, vessels, and nerves while observing the tumor contour. CONCLUSIONS: The laparoscopic transabdominal approach is an effective method for treating presacral tumors in obese patients.

Parenchymatous glossitis: A case report.

We present a case of parenchymatous glossitis with unilateral severe inflammation of the hyoglossus muscle, resulting in laryngeal edema. The route of inflammation was unique. Contrast-enhanced CT was useful for diagnosis. Administration of sensitive antibiotics led to improvement. Creatine phosphokinase may be an indicator of diagnosis and treatment response.

Squamous cell papilloma of the hypopharynx with elongated villous projections.

Squamous cell papilloma with elongated villous projections may occur in the hypopharynx and present with symptoms observable on physical examination.

Surgical management of secondary acquired cholesteatoma depends on its characteristics.

OBJECTIVE: Cholesteatoma secondary to tympanic perforation, known as "secondary acquired cholesteatoma" may progress slower than a retraction pocket cholesteatoma, with less bone destruction and fewer intracranial complications. However, complete surgical removal remains difficult because the pathological epithelium on the marginal side of the extension is not covered by the subepithelial layer of the cholesteatoma matrix, making the boundary with the middle ear mucosa difficult to identify. Therefore, considering the pathophysiology of secondary acquired cholesteatoma, suitable preoperative evaluation and surgical techniques are required. In this study, we aimed to evaluate (i) the extension of secondary acquired cholesteatoma according to the size and location of tympanic membrane perforation; and (ii) the microscopic surgical outcomes, including the rate of residual cholesteatoma, requirement for specialized surgical management, and changes in hearing. METHODS: This retrospective study included data of cases with secondary acquired cholesteatoma (n = 66; 66 ears of 64 patients, 2 patients had bilateral ear involvement), including those who underwent a staged operation (n = 25). RESULTS: The perforation level of the tympanic membrane was associated with the cholesteatoma extension. When the cholesteatoma extended around the stapes, staged operation was chosen. Six cases of spontaneous resolution of stapes lesions at the time of staged surgery were observed. A significant postoperative improvement in hearing was observed; however, five cases experienced sensorineural hearing loss. CONCLUSION: Surgery, including staged surgery of the stapes lesions, along with careful observation of the perforation, is required in secondary acquired cholesteatoma. For lesions that are visible yet challenging to remove, it is imperative to exercise prudent judgment, taking into account the possibility of spontaneous resolution.

Procedural characteristics and cardiovascular outcomes in patients undergoing drug-coated balloon angioplasty for de novo lesions in large coronary arteries: an observational study.

Limited data exist regarding drug-coated balloon (DCB) treatment in de novo large coronary arteries. We sought to demonstrate procedural characteristics, residual stenosis, and clinical outcomes following DCB angioplasty for de novo lesions in large versus small coronary arteries. The study included 184 consecutive patients with 223 de novo coronary lesions undergoing paclitaxel DCB angioplasty between January 2019 and August 2020, who were divided according to whether the DCB diameter was ≥ 3.0 mm (large group, n = 58) or < 3.0 mm (small group, n = 125). The large group had a higher proportion of acute coronary syndrome more commonly with ostial, bifurcation, and calcified lesions in large vessels and received lesion preparation with more frequent use of scoring or cutting balloons and atherectomy devices compared to the small group. Postprocedural angiographic diameter stenosis was smaller in the large group compared to the small group (31% [22-37] vs. 35% [26-42], p = 0.032), and intravascular ultrasound revealed no significant difference in postprocedural area stenosis between the groups (66.2 ± 7.7% vs. 67.9 ± 7.8%; p = 0.26). The median follow-up duration was 995 days. The incidence of a composite of all-cause death, myocardial infarction, stroke, or target lesion revascularization was similar between the groups (log-rank p = 0.41) and was influenced by the presence of acute coronary syndrome and anemia but not by DCB diameter. The rate of cardiovascular outcomes after DCB treatment was comparable in de novo large and small coronary arteries. Notably, well-planned lesion preparation with intravascular imaging guidance was prevalent in large vessels.

A manual of Eustachian tube function tests-illustration of representative test results obtained from healthy subjects and typical disorders with suggestion of the appropriate test method of choice.

In the 19th century, Politzer devised a method to measure passage of the Eustachian tube (ET) by pressurizing the nasopharyngeal cavity, which marked the beginning of the ET function test. Since then, various examination methods have been developed. While ET function testing is important, recent advancements in diagnostic imaging and treatments have renewed interest on its importance. In Japan, the main objective methods used for examining ET function include tubotympanoaero-dynamic graphy (TTAG), sonotubometry, and the inflation-deflation test. The Japan Otological Society (JOS) Eustachian Tube Committee has proposed a manual of ET function tests, which presents typical patterns of the normal ear and typical diseases and suggests the ET function test of choice for each disease. However, the diagnosis of each disease should be made based on a comprehensive history and various examination findings, with ET function tests playing a supplemental role in the diagnosis.

Impact of prolonged drug-coated balloon inflation on residual stenosis and clinical outcomes in coronary artery disease patients: A propensity score matched analysis.

BACKGROUND: There is a paucity of data regarding the optimal duration of drug-coated balloon (DCB) inflation for coronary lesions. We sought to explore the effect of DCB angioplasty with versus without long inflation time on residual stenosis and clinical outcomes in patients with coronary artery disease. METHODS: This study included 314 consecutive patients with 445 lesions undergoing paclitaxel DCB angioplasty using different inflation time, divided according to whether the total inflation time of the DCB was ≥180 s (prolonged group) or <180 s (standard group). The primary clinical endpoint, defined as a composite of all-cause death, myocardial infarction, stroke, or target lesion revascularization, was examined in 92 propensity score matched pairs. RESULTS: In the matched cohort, the median clinical follow-up period was 947 days. Postprocedural angiographic diameter stenosis was smaller in the prolonged group than in the standard group (30.0% [22.0-37.0] vs. 33.5% [25.5-40.5]; p = 0.042). Intravascular ultrasound measurements revealed that longer DCB inflation time resulted in smaller area stenosis (66.6 ± 7.8% vs. 69.4 ± 7.0%; p = 0.044) and a less mean increase in percent atheroma volume (-11.2 ± 7.1% vs. -7.4 ± 5.9%; p = 0.004) after angioplasty. The rate of the primary endpoint was lower in the prolonged group than in the standard group (log-rank p = 0.025). The efficacy of prolonged DCB inflation was prominent in patients with in-stent restenosis and longer lesions. CONCLUSION: Prolonged DCB inflation was associated with reduced residual stenosis and improved clinical outcomes in patients with coronary artery disease undergoing percutaneous coronary intervention. Prospective randomized trials are warranted to validate the benefits of DCB angioplasty with long inflation time.

Isotopic Evidence for Microbial Nitrogen Cycling in a Glacier Interior of High-Mountain Asia.

Glaciers are now acknowledged as an important biome globally, but biological processes in the interior of the glacier (englacial) are thought to be slow and to play only a minor role in biogeochemical cycles. In this study, we demonstrate extensive, microbially driven englacial nitrogen cycling in an Asian glacier using the stable isotopes (δ15N, δ18O, and Δ17O values) of nitrate. Apparent decreases in Δ17O values of nitrate in an 8 m shallow firn core from the accumulation area indicate that nitrifiers gradually replaced ∼80% of atmospheric nitrate with nitrate from microbial nitrification on a decadal scale. Nitrate concentrations did not increase with depth in this core, suggesting the presence of nitrate sinks by microbial assimilation and denitrification within the firn layers. The estimated englacial metabolic rate using isotopic mass balance was classified as growth metabolism, which is approximately 2 orders of magnitude more active than previously known cold-environment metabolisms. In a 56 m ice core from the interior of the ablation area, we found less nitrification but continued microbial nitrate consumption, implying that organic matter is microbially accumulated over centuries before appearing on the ablating surface. Such englacial microbial products may support supraglacial microbes, potentially promoting glacial darkening and melting. With predicted global warming and higher nitrogen loads, englacial nutrient cycling and its roles may become increasingly important in the future.

Association of probiotic use with nivolumab effectiveness against various cancers: A multicenter retrospective cohort study.

BACKGROUND: Previous studies have revealed an association between probiotic use and effectiveness of immune checkpoint inhibitors in renal and lung cancers. However, little is known regarding other cancers, including gastrointestinal cancer. METHODS: To address this issue, we conducted a multicenter retrospective cohort study and the duration of nivolumab treatment for various cancers was compared between probiotic users and non-users. RESULTS AND CONCLUSIONS: In total, 488 patients who received nivolumab therapy were included. In all cancers, no significant differences in treatment duration of nivolumab were observed between probiotic users and non-users (median 62.0 vs. 56.0, hazard ratio = 1.02, p = 0.825), whereas probiotic use, compared with non-use, in patients with gastric cancer was significantly associated with a longer duration of nivolumab treatment (55.0 vs. 31.0 days, hazard ratio = 0.69, p = 0.039). In conclusion, probiotics may improve the response to nivolumab and potentially prolong progression-free survival in patients with gastric cancer.

Comparison of long-term quality of life based on surgical procedure in patients with rectal cancer.

Introduction: Reports on the long-term quality of life (QOL) over 3 years after surgery in patients who have undergone surgery for rectal cancer are limited. Therefore, we aimed to evaluate the long-term QOL of patients who underwent high anterior resection (HAR), low anterior resection (LAR), internal sphincter resection (ISR), or abdominoperineal resection (APR) for rectal cancer. Methods: A questionnaire regarding QOL was sent to 360 patients with rectal cancer who underwent curative resection by HAR, LAR, ISR, or APR between January 2005 and December 2015. QOL was assessed using the short-form 36 (SF-36) and modified fecal incontinence QOL (mFIQL) questionnaire. QOL between surgical procedures was analyzed using a multivariate model adjusted for age, sex, and postoperative time. Results: A total of 144 patients responded with a median follow-up period of 94 months (range 38-233 months). According to surgical procedure, HAR was performed in 26 patients, LAR in 80 patients, ISR in 32 patients, and APR in 6 patients. Patients who underwent HAR had significantly better mFIQL scores than those who underwent LAR and ISR (p=0.013 and p=0004, respectively) and significantly better role/social component summary scores on the SF-36 subscales (p=0.007). No difference was observed in the mFIQL scores between patients who underwent ISR and those who underwent APR (p=0.8423). In addition, postoperative anastomotic leakage sutures did not influence the mFIQL and SF-36 scores after surgery. Conclusion: The QOL of patients who underwent anus-preserving surgery was best in the HAR group, with the QOL of other groups similar to the APR group. These results suggest that anus- preserving surgery is acceptable from a QOL standpoint. However, a colostomy may be a more satisfactory procedure in some patients.

Deep Subseafloor Biogeochemical Processes and Microbial Populations Potentially Associated with the 2011 Tohoku-oki Earthquake at the Japan Trench Accretionary Wedge (IODP Expedition 343).

Post-mega-earthquake geochemical and microbiological properties in subseafloor sediments of the Japan Trench accretionary wedge were investigated using core samples from Hole C0019E, which was drilled down to 851| |m below seafloor (mbsf) at a water depth of 6,890 m. Methane was abundant throughout accretionary prism sediments; however, its concentration decreased close to the plate boundary decollement. Methane isotope systematics indicated a biogenic origin. The content of mole-cular hydrogen (H2) was low throughout core samples, but markedly increased at specific depths that were close to potential faults predicted by logging-while-drilling ana-lyses. Based on isotopic systematics, H2 appeared to have been abundantly produced via a low-temperature interaction between pore water and the fresh surface of crushed rock induced by earthquakes. Subseafloor microbial cell density remained constant at approximately 105| |cells| |mL-1. Amplicon sequences revealed that predominant members at the phylum level were common throughout the units tested, which also included members frequently found in anoxic subseafloor sediments. Metabolic potential assays using radioactive isotopes as tracers revealed homoacetogenic activity in H2-enriched core samples collected near the fault. Furthermore, homoacetogenic bacteria, including Acetobacterium carbinolicum, were isolated from similar samples. Therefore, post-earthquake subseafloor microbial communities in the Japan Trench accretionary prism appear to be episodically dominated by homoacetogenic populations and potentially function due to the earthquake-induced low-temperature generation of H2. These post-earthquake microbial communities may eventually return to the steady-state communities dominated by oligotrophic heterotrophs and hydrogenotrophic and methylotrophic methanogens that are dependent on refractory organic matter in the sediment.

Application of elemental analysis-coupled isotope ratio mass spectrometry for protein turnover analysis using deuterium labeling: Purification and analysis of hydrogen isotope ratio of non-derivatized protein-bound alanine.

RATIONALE: Heavy water can be used as a tracer for the evaluation of protein turnover. By adding heavy water (D2 O) to the precursor pool, nonessential amino acids, including alanine, can be isotopically labeled in vivo. Protein turnover can then be quantified by measuring the hydrogen isotope ratio of protein-bound alanine. METHODS: In this study, we constructed a novel method to apply deuterium labeling of alanine to the evaluation of protein turnover using elemental analysis-coupled isotope ratio mass spectrometry (EA-IRMS). We established a preparative high-performance liquid chromatography method to isolate alanine from protein hydrolysates. EA-IRMS was then used to determine the hydrogen isotope ratio of alanine isolated from hydrolysates of protein from mouse myoblast C2C12 cells that had been treated with D2 O over the course of 72 h. RESULTS: In cells treated with 4% D2 O, the deuterium enrichment of alanine increased to approximately 0.9% over time, while that of cells treated with 0.017% D2 O increased to approximately 0.006%. The rate of protein synthesis calculated by fitting the increase of deuterium excess to rise-to-plateau kinetics was similar regardless of the concentration of D2 O. When C2C12 cells treated with insulin and rapamycin were analyzed 24 h after the addition of 0.017% D2 O, protein turnover was found to be accelerated by insulin, but this effect was offset by co-treatment with rapamycin. CONCLUSION: The derivative-free measurement of the hydrogen isotope ratio of protein-bound alanine using EA-IRMS can be applied to the evaluation of protein turnover. The proposed method is an accessible option for many laboratories to perform highly sensitive IRMS-based evaluations of protein metabolic turnover.

Ecological Dynamics of Broad- and Narrow-Host-Range Viruses Infecting the Bloom-Forming Toxic Cyanobacterium Microcystis aeruginosa.

Microcystis aeruginosa is predicted to interact and coexist with diverse broad- and narrow-host-range viruses within a bloom; however, little is known about their affects on Microcystis population dynamics. Here, we developed a real-time PCR assay for the quantification of these viruses that have different host ranges. During the sampling period, total Microcystis abundance showed two peaks in May and August with a temporary decrease in June. The Microcystis population is largely divided into three phylotypes based on internal transcribed sequences (ITS; ITS types I to III). ITS I was the dominant phylotype (66% to 88%) except in June. Although the ITS II and III phylotypes were mostly less abundant, these phylotypes temporarily increased to approximately equivalent abundances of the ITS I population in June. During the same sampling period, the abundances of the broad-host-range virus MVGF_NODE331 increased from April to May and from July to October with a temporary decrease in June, in which its dynamics were in proportion to the increase of total Microcystis abundances regardless of changes in host ITS population composition. In contrast, the narrow-host-range viruses MVG_NODE620 and Ma-LMM01 were considerably less abundant than the broad-host-range virus and generally did not fluctuate in the environment. Considering that M. aeruginosa could increase the abundance and sustain the bloom under the prevalence of the broad-host-range virus, host abundant and diverse antiviral mechanisms might contribute to coexistence with its viruses. IMPORTANCE The bloom-forming toxic cyanobacterium Microcystis aeruginosa interacts with diverse broad- and narrow-host-range viruses. However, the dynamics of the Microcystis population (at the intraspecies level) and viruses with different host ranges remain unknown. Our real-time PCR assays unveiled that the broad-host-range virus gradually increased in abundance over the sampling period, in proportion to the increase in total Microcystis abundance regardless of changes in genotypic composition. The narrow-host-range viruses were considerably less abundant than the broad-host-range virus and did not generally fluctuate in the environment. The expansion and maintenance of the Microcystis bloom even under the increased infection by the broad-host-range virus suggested that highly abundant and diverse antiviral mechanisms allowed them to coexist with viruses under selective pressure. This paper expands our knowledge about the ecological dynamics of Microcystis viruses and provides potential insights into their coexistence with their host.