Clinical utility of MR spectroscopy for gynecological pelvic abscesses using next-generation sequencing technology for the detection of causative bacteria.

Due to the invasiveness of sample collection, treatment for an abscess in the pelvis, such as a gynecological abscess, is often started without a culture test. A test that could predict the appropriate antibiotic and clinical course without invasiveness prior to treatment initiation would be useful. Magnetic resonance spectroscopy (MRS) can be used to detect metabolites in an abscess and has the potential for evaluation of gynecological abscesses. The present study investigated the use of MRS for the evaluation of gynecological abscesses, using next-generation sequencing (NGS) for detection of true pathogenic bacteria. A total of 16 patients with a gynecological abscess who were treated at Keio University Hospital (Tokyo, Japan) from July 2015 to September 2016 and underwent MRS were recruited to the present study. If available, samples from drainage or surgery were used for detection of true pathogenic bacteria based on analyses of bacterial flora using NGS of 16S ribosomal DNA. MRS signals, NGS results and clinical course were then compared. All patients gave written informed consent after receiving an oral explanation of the study and the study was approved by the institutional research ethics committee. Of the 16 patients, six had MRS signals with a specific peak at 1.33 ppm, which suggested the presence of lipid or lactic acid. However, there was no significant association between metabolism, MRS signals, pathogenesis and clinical course. Only in cases of infectious lymphocele were there cases with a lactic acid peak that seemed to improve without drainage. In conclusion, the present study was not able to show marked usefulness of MRS for the identification of pathogenic bacteria and prediction of the clinical course; however, MRS may be useful for predicting the need for drainage in patients with infectious lymphocele. This study was registered as a clinical trial in the UMIN Clinical Trials Registry (registration no. UMIN000016705) on March 11, 2015.

Response Predictive Markers and Synergistic Agents for Drug Repositioning of Statins in Ovarian Cancer.

In the field of drug repurposing, the use of statins for treating dyslipidemia is considered promising in ovarian cancer treatment based on epidemiological studies and basic research findings. Biomarkers should be established to identify patients who will respond to statin treatment to achieve clinical application. In the present study, we demonstrated that statins have a multifaceted mode of action in ovarian cancer and involve pathways other than protein prenylation. To identify biomarkers that predict the response to statins, we subjected ovarian cancer cells to microarray analysis and calculated Pearson's correlation coefficients between gene expression and cell survival after statin treatment. The results showed that VDAC1 and LDLRAP1 were positively and negatively correlated with the response to statins, respectively. Histoculture drug response assays revealed that statins were effective in clinical samples. We also confirmed the synergistic effects of statins with paclitaxel and panobinostat and determined that statins are hematologically safe to administer to statin-treated mice. Future clinical trials based on the expression of the biomarkers identified in this study for repurposing statins for ovarian cancer treatment are warranted.

Impact of COVID-19 on gynecologic cancer treatment in Japan: a nationwide survey by the Japan Society of Gynecologic Oncology (JSGO).

OBJECTIVE: As coronavirus disease 2019 (COVID-19) rages on, it is a challenging task to balance resources for treatment of COVID-19 and malignancy-based treatment. For the development of optimal strategies, assessing the conditions and constrains in treatment during the COVID-19 pandemic is pertinent. This study reported about a nationwide survey conducted by the Japan Society of Gynecologic Oncology. METHODS: We interviewed 265 designated training facilities about the state of their clinical practice from the time period between March and December 2020. We asked the facility doctors in charge to fill a web-based questionnaire. RESULTS: A total of 232 facilities (87.5%) responded. A decrease in the number of outpatient visits was reported, and the major reason attributed was reluctance of patients to visit hospitals rather than facility restrictions. The actual number of surgeries decreased by 3.9%, compared to 2019. There was a significant difference when the variable of "Prefectures operating under special safety precautions" or not was introduced. There was no increase in the rate of advanced stages in the three cancer types studied. However, 34.1% participants perceived COVID-19 affected management and prognosis. CONCLUSION: Refraining from visiting hospitals based on the patient's judgment may be expected to be an issue in the future. No significant decrease in surgeries was observed, and it would seem that there were few forced changes in treatment plans, but "the State of Emergency" had an impact. There was no increase in the rate of advanced cancers, but this will need to be monitored.

Impact of COVID-19 on cervical cancer screening in Japan: A survey of population-based screening in urban Japan by the Japan Society of Gynecologic Oncology.

AIM: To assess the impact of COVID-19 on cervical cancer screening. METHOD: The Japanese Society of Gynecologic Oncology launched COVID-19 Task Force surveyed the municipalities in urban areas of Japan. Questionnaires were sent to 20 ordinance-designated cities and 23 wards of Tokyo metropolitan area in Japan via telephone and mail in January 2021. An additional survey was conducted in March and April 2021, counted the monthly checkups in 2020 and, as a control data, the number of monthly checkups in 2019. "The State of Emergency" between April 7 and May 25, 2020, included 13 prefectures. The data collected in this research involved the number of screenings only. The chi-square test was performed for statistical analysis. RESULTS: The number of cancer screenings from March to August, with May being the month with the lowest number of screenings, was less than 50% of that in the previous year. In particular, the drop in the number of cancer screenings in the "Prefectures operating under special safety precautions" was remarkable and significantly lower than that in other Prefectures. However, after August, the number recovered to the usual level, despite the second wave of the pandemic occurring nationwide. The initial "the State of Emergency" caused a significant decrease in the number of people receiving population-based screenings, but the recovery has been remarkable, and the total number is expected to be the same as in previous years. CONCLUSION: The initial "the State of Emergency" caused a significant decrease in the number of people receiving population-based screenings.

Impact of the COVID-19 epidemic at a high-volume facility in gynecological oncology in Tokyo, Japan: a single-center experience.

BACKGROUND: The number of cases of novel coronavirus disease 2019 (COVID-19) in Japan have risen since the first case was reported on January 24, 2020, and 6225 infections have been reported as of June 30, 2020. On April 8, 2020, our hospital began screening patients via pre-admission reverse transcriptase-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and chest computed tomography (CT). Although no patients exhibited apparent pneumonia, treatment delay or changes in treatment plans were required for a few patients based on the results of screening tests. During an emerging infectious disease pandemic, the likelihood of being infected, as well as the disease itself, affects clinical decision making in several ways. We summarized and presented our experience. CASE PRESENTATION: After the introduction of pre-admission screening, RT-PCR and CT were performed in 200 and 76 patients, respectively, as of June 30, 2020. The treatment of five patients, including two patients with cervical cancer, two patients with ovarian tumors, and one patient with ovarian cancer, was affected by the results. Two asymptomatic RT-PCR-positive patients did not develop COVID-19, but their treatment was delayed until the confirmation of negative results. The other three patients were RT-PCR-negative, but abnormal CT findings suggested the possibility of COVID-19, which delayed treatment. The patients receiving first-line preoperative chemotherapy for ovarian cancer had clinically evident exacerbations because of the treatment delay. CONCLUSION: During the epidemic phase of an emerging infectious disease, we found that COVID-19 has several other effects besides its incidence. The postponing treatment was the most common, therefore, treatment of ovarian tumors and ovarian cancer was considered to be the most likely to be affected among gynecological diseases. Protocols that allow for easy over-diagnosis can be disadvantageous, mainly because of treatment delays, and therefore, the protocols must be developed in light of the local infection situation.

Erratum: Aurora kinase inhibitors: Potential molecular-targeted drugs for gynecologic malignant tumors (Review).

[This corrects the article DOI: 10.3892/br.2013.91.].

Profiling of the Causative Bacteria in Infected Lymphocysts after Lymphadenectomy for Gynecologic Cancer by Pyrosequencing the 16S Ribosomal RNA Gene Using Next-Generation Sequencing Technology.

Background: Surgery for gynecologic cancer with lymphadenectomy and pelvic radiotherapy can produce lymphoceles that sometimes complicate with infection, resulting in abscesses. The true pathogenic bacteria of abscesses are not always found because of false-negative results due to administered antibiotics and difficulty with detection, including for anaerobic bacteria. Analyzing bacteria flora by next-generation sequencing (NGS) using 16S ribosomal DNA may reveal the true pathogenic bacteria in abscesses. This is the first report on causative pathogens for infectious lymphocele using this technology. Methods: The subjects were patients who developed infectious lymphocele after surgery for gynecologic cancer at our hospital from July 2015 to September 2016. NGS analyses of bacterial flora were performed using specimens preserved at -80°C. Two steps of PCR were performed for purified DNA samples to obtain sequence libraries. Processing of sequence data, including operational taxonomic unit (OTU) definition, taxonomy assignment, and an OTU BLAST search were performed. All patients gave written informed consent and the study was approved by the institutional research ethics committee. Results: Six patients underwent puncture and drainage. The result in most cases indicated a single causative pathogen, including Staphylococcus lugdunensis, Streptococcus dysgalactiae, Streptococcus equinus, Enterococcus saccharolyticus, and Escherichia coli. Conclusions. NGS revealed that the causative bacteria in lymphocele infection are normally a single strain, such as a surface Gram-positive coccus or enteric bacteria. Antibiotics should be chosen as appropriate for elimination of these respective bacteria.

Aberrant chromatin remodeling in gynecological cancer.

Epigenetic regulatory mechanisms are a current focus in studies investigating cancer. Chromatin remodeling alters chromatin structure and regulates gene expression, and aberrant chromatin remodeling is involved in carcinogenesis. AT-rich interactive domain-containing protein 1A (ARID1A) and SWItch/sucrose non-fermentable-related, matrix-associated, actin-dependent regulator of chromatin, subfamily a, member 4 are remodeling factors that are mutated in numerous types of cancer. In gynecological cancer, ARID1A mutations have been identified in 46-57% of clear cell carcinoma and 30% of endometrioid carcinoma. Mutations of chromodomain helicase, DNA-binding protein 4 have been detected in 17-21% of endometrial serous cancer, and mutations of ARID1A and mixed-lineage leukemia 3 occur in 36 and 27% of uterine carcinosarcoma, respectively. These data suggest that aberrant chromatin remodeling is a potential cause of cancer, and have led to the development of novel proteins targeting these processes. Additional accumulation of information on the mechanisms of chromatin remodeling and markers for these events may promote personalized anticancer therapies.

Allowable warm ischemic time and morphological and biochemical changes in uterine ischemia/reperfusion injury in cynomolgus macaque: a basic study for uterus transplantation.

STUDY QUESTION: How long is the allowable warm ischemic time of the uterus and what morphological and biochemical changes are caused by uterine ischemia/reperfusion injury in cynomolgus macaques? SUMMARY ANSWER: Warm ischemia in the uterus of cynomolgus macaques is tolerated for up to 4 h and reperfusion after uterine ischemia caused no further morphological and biochemical changes. WHAT IS KNOWN ALREADY: Uterus transplantation is a potential option for women with uterine factor infertility. The allowable warm ischemic time and ischemia/reperfusion injury of the uterus in humans and non-human primates is unknown. STUDY DESIGN, SIZE, DURATION: This experimental study included 18 female cynomolgus macaques with periodic menstruation. PARTICIPANTS/MATERIALS, SETTING, METHODS: Animals were divided into six groups of three monkeys each: a control group and groups with uterine ischemia for 0.5, 1, 2, 4 and 8 h. Biopsies of uterine tissues were performed before blood flow blockage, after each blockage time, and after reperfusion for 3 h. Blood sampling was performed after each blockage time, and after reperfusion for 5, 15 and 30 min for measurement of biochemical data. Resumption of menstruation was monitored after the surgical procedure. Morphological, physiological and biochemical changes after ischemia and reperfusion were evaluated. MAIN RESULTS AND THE ROLE OF CHANCE: Mild muscle degeneration and zonal degeneration were observed in all animals subjected to warm ischemia for 4 or 8 h, but there were no marked differences in the appearance of specimens immediately after ischemia and after reperfusion for 3 h in animals subjected to 4 or 8 h of warm ischemia. There were no significant changes in any biochemical parameters at any time point in each group. Periodical menstruation resumed in all animals with warm ischemia up to 4 h, but did not recover in animals with warm ischemia for 8 h with atrophic uteri. LIMITATIONS, REASON FOR CAUTION: Warm ischemia in actual transplantation was not exactly mimicked in this study because uteri were not perfused, cooled, transplanted or reanastomosed with vessels. Results in non-human primates cannot always be extrapolated to humans. WIDER IMPLICATIONS OF THE FINDINGS: The findings suggest that the tolerable warm ischemia time in the uterus is expected to be longer than that in other vital organs. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI Grant Number 26713050. None of the authors has a conflict of interest to declare.

Genome-wide analysis of gynecologic cancer: The Cancer Genome Atlas in ovarian and endometrial cancer.

Cancer typically develops due to genetic abnormalities, but a single gene abnormality cannot completely account for the onset of cancer. The Cancer Genome Atlas (CGA) project was conducted for the cross-sectional genome-wide analysis of numerous genetic abnormalities in various types of cancer. This approach has facilitated the identification of novel AT-rich interaction domain 1A gene mutations in ovarian clear cell carcinoma, frequent tumor protein 53 (TP53) gene mutations in high-grade ovarian serous carcinoma, and Kirsten rat sarcoma and B-rapidly accelerated fibrosarcoma proto-oncogene, serine/threonine kinase gene mutations in low-grade ovarian serous carcinoma. Genome-wide analysis of endometrial cancers has led to the establishment of four subgroups: Polymerase ultramutated, microsatellite instability hypermutated, genome copy-number low and genome copy-number high. These results may facilitate the improvement of the prediction of patient prognosis and therapeutic sensitivity in various types of gynecologic cancer. The enhanced use of currently available therapeutic agents and the development of novel drugs may be facilitated by the novel classification of ovarian cancer based on TP53 mutations, the efficacy of poly (ADP-ribose) polymerase inhibitors for tumors with breast cancer 1/2 mutations and the effect of phosphoinositide-3-kinase (PI3K)/mammalian target of rapamycin inhibitors for tumors with mutations in the PI3K/protein kinase B signaling pathway. Important results have been revealed by genome-wide analyses; however, the pathogenic underlying mechanisms of gynecologic cancer will require further studies and multilateral evaluation using epigenetic, transcriptomic and proteomic analyses, in addition to genomic analysis.

Methylation Analysis of DNA Mismatch Repair Genes Using DNA Derived from the Peripheral Blood of Patients with Endometrial Cancer: Epimutation in Endometrial Carcinogenesis.

Germline mutation of DNA mismatch repair (MMR) genes is a cause of Lynch syndrome. Methylation of MutL homolog 1 (MLH1) and MutS homolog 2 (MSH2) has been detected in peripheral blood cells of patients with colorectal cancer. This methylation is referred to as epimutation. Methylation of these genes has not been studied in an unselected series of endometrial cancer cases. Therefore, we examined methylation of MLH1, MSH2, and MSH6 promoter regions of peripheral blood cells in 206 patients with endometrial cancer using a methylation-specific polymerase chain reaction (MSP). Germline mutation of MMR genes, microsatellite instability (MSI), and immunohistochemistry (IHC) were also analyzed in each case with epimutation. MLH1 epimutation was detected in a single patient out of a total of 206 (0.49%)-1 out of 58 (1.72%) with an onset age of less than 50 years. The patient with MLH1 epimutation showed high level MSI (MSI-H), loss of MLH1 expression and had developed endometrial cancer at 46 years old, complicated with colorectal cancer. No case had epimutation of MSH2 or MSH6. The MLH1 epimutation detected in a patient with endometrial cancer may be a cause of endometrial carcinogenesis. This result indicates that it is important to check epimutation in patients with endometrial cancer without a germline mutation of MMR genes.

Surgical technique for allogeneic uterus transplantation in macaques.

No study has reported an animal model of uterus transplantation (UTx) using cynomolgus macaques. We aimed to establish a surgical technique of allogeneic UTx assuming the recovery of a uterus from a deceased donor in cynomolgus macaques. Four allogeneic UTxs were performed in female cynomolgus macaques. Donor surgeries comprised en bloc recovery of organs with iliac vessels on both sides, and/or abdominal aorta/vena cava after sufficient perfusion from one femoral artery or external iliac artery. Before perfusion, 150 mL of whole blood was obtained from the donor for subsequent blood transfusion to the recipient. Four uterine grafts were orthotopically transplanted to recipients. End-to-side anastomosis was performed to the iliac vessels on one side in case 1 and iliac vessels on both sides in case 2; aorto-aorto/cavo-caval anastomosis was performed in cases 3 and 4. Arterial blood flow of the uterine grafts was determined by intraoperative indocyanine green (ICG) angiography. ICG angiography results showed sufficient blood flow to all uterine grafts, and anaemia did not progress. Under appropriate immune suppression, all recipients survived for more than 90 days post-transplantation, without any surgical complications. We describe a surgical technique for allogeneic UTx in cynomolgus macaques.

Evaluation of allowable time and histopathological changes in warm ischemia of the uterus in cynomolgus monkey as a model for uterus transplantation.

INTRODUCTION: The objective of this study was to examine the allowable warm ischemic time and pathological changes due to ischemia and reperfusion injury in the uterus of the cynomolgus monkey as a model for uterus transplantation. MATERIAL AND METHODS: Six female cynomolgus monkeys were used in the study. The uterus was resected from the vaginal canal and connected through the bilateral ovarian and uterine arteries and veins only. One animal was used as a control. In the other five animals, the bilateral uterine and ovarian vessels were clamped for 0.5, 1, 2, 4 and 8 h, respectively. Biopsy of the smooth muscle tissue of corpus uteri was performed after each ischemic time and after subsequent reperfusion for 3 h. Biopsy samples were observed by light and electron microscopy. Menstruation recovery was monitored. RESULTS: There were no particular findings in both light and electron microscopy after ischemia for up to 2 h and after subsequent reperfusion. There were no marked changes after ischemia for 4 h, but dilated nuclear pores and rough endoplasmic reticulum swelling were found after reperfusion. These changes also occurred, along with mitochondrial swelling and cristae loss after ischemia for 8 h, and plasma membrane loss, nuclear fragmentation and chromatin condensation were found after reperfusion. Periodical menstruation restarted in all animals with ischemia up to 4 h, but the animal with ischemia for 8 h had amenorrhea and uterine atrophy. CONCLUSIONS: The uterus of the cynomolgus monkey tolerates warm ischemia for up to 4 h.

Anisakiasis mimics cancer recurrence: two cases of extragastrointestinal anisakiasis suspected to be recurrence of gynecological cancer on PET-CT and molecular biological investigation.

BACKGROUND: We report two cases of anisakiasis lesions that were initially suspected to be recurrence of gynecological cancer by positron emission tomography-computed tomography (PET-CT). Both cases were extragastrointestinal anisakiasis that is very rare. CASE PRESENTATION: The first case was a patient with endometrial cancer. At 19 months after surgery, a new low density area of 2 cm in diameter in liver segment 4 was found on follow-up CT. In PET-CT, the lesion had abnormal (18)fluoro-deoxyglucose (FDG) uptake with elevation in the delayed phase, with no other site showing FDG uptake. Partial liver resection was performed. A pathological examination revealed no evidence of malignancy, but showed necrotic granuloma with severe eosinophil infiltration and an irregular material with a lumen structure in the center. Parasitosis was suspected and consultation with the National Institute of Infectious Diseases (NIID) showed the larvae to be Anisakis simplex sensu stricto by genetic examination. The second case was a patient with low-grade endometrial stromal sarcoma (LG-ESS). At 8 months after surgery, swelling of the mediastinal lymph nodes was detected on CT and peripheral T-cell lymphoma was diagnosed by biopsy. A new peritoneal lesion with abnormal FDG uptake was detected on pre-treatment PET-CT and this lesion was increased in size on post-treatment PET-CT. Tumorectomy was performed based on suspected dissemination of LG-ESS recurrence. The findings in a pathological examination were similar to the first case and we again consulted the NIID. The larvae was identified as Anisakis pegreffi, which is a rare pathogen in humans. Having experienced these rare cases, we investigated the mechanisms of FDG uptake in parasitosis lesions by immunohistochemical staining using antibodies to glucose transporter type 1 (GLUT-1) and hexokinase type 2 (HK-2). While infiltrated eosinophils were negative, macrophages demonstrated positive for both antibodies. Therefore, mechanisms behind FDG uptake may involve macrophages, which is common among various granulomas. This is the first report to investigate parasitosis in such a way. CONCLUSION: These cases suggest that anisakiasis is a potential differential diagnosis for a lesion with FDG uptake in PET-CT, and that it is difficult to distinguish this disease from a recurrent tumor using PET-CT alone.

Metformin: A candidate for the treatment of gynecological tumors based on drug repositioning.

Metformin is a first-line drug used for the treatment of type 2 diabetes. Recently, metformin has been reported to reduce the carcinogenic risk and inhibit tumor cell growth in glioma and breast cancer. The anticancer action of metformin involves the enhancement of phosphorylation of liver kinase B1, activation of adenosine monophosphate-activated protein kinase and inhibition of mammalian target of rapamycin, which reduces cell growth. Metformin is anticipated to exert antitumor effects in gynecological cancer, and its efficacy for the treatment of endometrial, breast and ovarian cancer has been suggested in preclinical studies and clinical trials. Although the effect of metformin on cervical cancer remains to be examined in clinical trials, its antitumor effects have been reported in preclinical studies. Thus, the use of metformin for the treatment of gynecological cancer may become a successful example of drug repositioning, following establishment of the drug's antitumor effects, risk evaluation, screening and validation of efficacy.

Intravenous low-grade endometrial stromal sarcoma with intracardiac extension: A CASE OF inaccurate tumor location on contrast-enhanced computed tomography.

We herein report a case of low-grade endometrial stromal sarcoma with intracardiac extension in a 58-year-old woman with a uterine tumor with intravascular involvement. The tumor was suspected preoperatively to be an endometrial stromal sarcoma by magnetic resonance imaging. The extent of intravascular involvement was determined to be below the level of the renal veins on preoperative contrast-enhanced computed tomography (CT). However, perioperative echography revealed that the tumor extended to the right atrium. An emergency cardiotomy with extracorporeal circulation was required. The risk of tumor embolism was reduced through transection of the inferior vena cava, but the tumor was difficult to remove completely. Postoperative hormonal therapy reduced the size of the residual tumor and no recurrence was detected for 1 year. The preoperative contrast-enhanced CT was unable to detect the free-floating intravascular tumor. This case illustrates a limitation of CT and indicates that accurate determination of the tumor extent for planning a surgical strategy in similar cases should be performed using multiple imaging methods.

ARID1A gene mutation in ovarian and endometrial cancers (Review).

The AT-rich interacting domain­containing protein 1A gene (ARID1A) encodes ARID1A, a member of the SWI/SNF chromatin remodeling complex. Mutation of ARID1A induces changes in expression of multiple genes (CDKN1A, SMAD3, MLH1 and PIK3IP1) via chromatin remodeling dysfunction, contributes to carcinogenesis, and has been shown to cause transformation of cells in association with the PI3K/AKT pathway. Information on ARID1A has emerged from comprehensive genome­wide analyses with next­generation sequencers. ARID1A mutations have been found in various types of cancer and occur at high frequency in endometriosis­associated ovarian cancer, including clear cell adenocarcinoma and endometrioid adenocarcinoma, and also occur at endometrial cancer especially in endometrioid adenocarcinoma. It has also been suggested that ARID1A mutation occurs at the early stage of canceration from endometriosis to endometriosis­associated carcinoma in ovarian cancer and also from atypical endometrial hyperplasia to endometrioid adenocarcinoma in endometrial cancer. Therefore, development of a screening method that can detect mutations of ARID1A and activation of the PI3K/AKT pathway might enable early diagnosis of endometriosis­associated ovarian cancers and endometrial cancers. Important results may also emerge from a current clinical trial examining a multidrug regimen of temsirolimus, a small molecule inhibitor of the PI3K/AKT pathway, for treatment of advanced ovarian clear cell adenocarcinoma with ARID1A mutation and PI3K/AKT pathway activation. Also administration of sorafenib, a multikinase inhibitor, can inhibit cancer proliferation with PIK3CA mutation and resistance to mTOR inhibitors and GSK126, a molecular­targeted drug can inhibit proliferation of ARID1A­mutated ovarian clear cell adenocarcinoma cells by targeting and inhibiting EZH2. Further studies are needed to determine the mechanism of chromatin remodeling dysregulation initiated by ARID1A mutation, to develop methods for early diagnosis, to investigate new cancer therapy targeting ARID1A, and to examine the involvement of ARID1A mutations in development, survival and progression of cancer cells.

A surgical technique using the ovarian vein in non-human primate models of potential living-donor surgery of uterus transplantation.

AIM: Living donor surgery in organ transplantation should be performed in a minimally invasive manner under conditions that are as safe as possible. The objective of this study is to examine whether the procedure for using the ovarian vein makes donor surgery less invasive in a cynomolgus monkey model of potential living-donor surgery of uterus transplantation. MATERIAL AND METHODS: Twenty-two female cynomolgus monkeys aged 6-9 years and with body weights of 3.55 ± 1.28 kg were used in the study. Vessels and tissues surrounding the uterus were dissected while preserving the uterine artery/vein. The deep uterine vein was used as a venous pedicle in four monkeys (Group 1), and the ovarian vein was used instead of the deep uterine vein in 18 monkeys (Group 2). With the uterine artery/vein and deep uterine vein (Group 1) or ovarian vein (Group 2) connected to the uterus, the vaginal canal was cut. The vessels were then clamped to produce a donor surgery model. Surgical time, intraoperative organ and vascular injury were examined in each animal. RESULTS: The average surgical time from laparotomy to clamping of vessels was 230 ± 112 min in all 22 cynomolgus monkeys, and significantly longer in Group 1 (n = 4) than in Group 2 (n = 18) (393 ± 71 vs. 194 ± 84 min, p < 0.05). Surgical time in Group 2 showed a tendency to decrease in animals treated later in the study, with a significantly longer time in the first 10 monkeys compared with the last 8 (253 ± 65 vs. 120 ± 26 min, p < 0.05). All monkeys had no complications, including no injuries to other organs and no unanticipated vascular injury. CONCLUSION: The procedure using the ovarian vein was less invasive than that using the deep uterine vein in mimicking living-donor surgery in a cynomolgus monkey model of uterus transplantation.