Franseen needle in endobronchial ultrasound-guided transbronchial needle aspiration: a phase II prospective study.

BACKGROUND: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has been used to diagnose and stage lung cancer. Acquire™ Pulmonary and Expect™ Pulmonary dedicated EBUS-TBNA needles were introduced as the Franseen and Lancet needles, respectively. It is still unclear whether the Franseen or Lancet needles yield a higher quality specimen especially focusing on next-generation sequencing-based molecular testing. METHODS: A single-center, prospective study performed at the Chiba University Hospital randomly assigned patients to two groups: Group A, wherein the first and second EBUS-TBNA were performed using Lancet and Franseen needles, respectively, and Group B, wherein the first and second EBUS-TBNA were performed using Franseen and Lancet needles, respectively. Each specimen was compared and analyzed pathologically. The primary outcome was the histological tissue area except blood clot and the cellularity of each sample. We also examined the success rate of molecular testing. RESULTS: Twelve patients who underwent EBUS-TBNA between November 2022 and February 2023 were enrolled in this study. The tissue area of the specimens obtained by the Franseen and Lancet needles was 13.3 ± 6.4 mm2 and 10.6 ± 6.3 mm2, respectively (P = .355). The tumor cellularity in the specimens obtained using the Franseen and Lancet needles was 54.0 ± 30.3 and 46.2 ± 36.3%, respectively (P = .608). The success rate of molecular testing using the single-pass sample by Franseen needle was 85.7 and 57.1% by Lancet needle. No serious complications were reported. CONCLUSIONS: The Franseen needle tended to show a greater amount of specimen with higher tumor cellularity than the Lancet needle which may contribute higher success rate of molecular testing. Further studies must be conducted to validate the results of this study. KEY FINDINGS: What is known and what is new?  What is the implication, and what should change now?

Carcinogenesis and epidemiology of cervical cancer: The hallmark of human papillomavirus-associated cancer.

Cervical cancer affects women worldwide and is the most common human papillomavirus (HPV)-associated cancer. Carcinogenesis caused by HPV results in specific cancer behavior because of the underlying viral infection. The mechanism and timing of the transformation from viral infection to cancer cells have been elucidated in detail. Treatments for this cancer are based on its characteristics and are being implemented. Moreover, HPV infection is widespread worldwide and is transmitted through sexual activity. Although the HPV vaccination is the most effective strategy of preventing cervical cancer, it is not feasible to vaccinate the entire human population especially in low- and middle-income countries. In order to consider the next step for HPV vaccination, we need to understand the characteristics of HPV carcinogenesis and cervical cancer. Additionally, treatment aimed at preservation of reproductive function in patients with cervical cancer is often required, as the cervix is a reproductive organ and because the disease is more prevalent in the adolescent and young adult generation. Thus, there are still many challenges in the diagnosis, treatment, and prevention of cervical cancer.

Highly Efficient Fluorescent Probe to Visualize Protein Interactions at the Superresolution.

Superresolution microscopy (SR microscopy) of protein-protein interactions (PPIs) occurring in subcellular structures is essential for understanding cellular functions. However, a powerful and useful technology for SR microscopy of PPIs remains elusive. Here, we develop a highly efficient photoconvertible fluorescent probe, named split-Dendra2, for SR microscopy of PPIs in the cell. We found that split-Dendra2 enables a highly efficient detection of PPIs, making it possible to perform SR microscopy of PPIs with high spatial resolution and high image reconstruction fidelity. We demonstrate the utility of split-Dendra2 by visualizing PPIs occurring in small subcellular structures at the superresolution, such as clathrin-coated pits and focal adhesions, which cannot be visualized by the existing tools. Split-Dendra2 offers a powerful and useful tool that greatly expands the possibility of SR microscopy and can contribute to revealing the function of PPIs at the nanoscale resolution.

The integration of metabolic and proteomic data uncovers an augmentation of the sphingolipid biosynthesis pathway during T-cell differentiation.

Recent studies have highlighted the significance of cellular metabolism in the initiation of clonal expansion and effector differentiation of T cells. Upon exposure to antigens, naïve CD4+ T cells undergo metabolic reprogramming to meet their metabolic requirements. However, only few studies have simultaneously evaluated the changes in protein and metabolite levels during T cell differentiation. Our research seeks to fill the gap by conducting a comprehensive analysis of changes in levels of metabolites, including sugars, amino acids, intermediates of the TCA cycle, fatty acids, and lipids. By integrating metabolomics and proteomics data, we discovered that the quantity and composition of cellular lipids underwent significant changes in different effector Th cell subsets. Especially, we found that the sphingolipid biosynthesis pathway was commonly activated in Th1, Th2, Th17, and iTreg cells and that inhibition of this pathway led to the suppression of Th17 and iTreg cells differentiation. Additionally, we discovered that Th17 and iTreg cells enhance glycosphingolipid metabolism, and inhibition of this pathway also results in the suppression of Th17 and iTreg cell generation. These findings demonstrate that the utility of our combined metabolomics and proteomics analysis in furthering the understanding of metabolic transition during Th cell differentiation.

Effects of case volume on short- and long-term outcomes following cadaveric lung transplantation in Japan.

Background: Despite the low number of lung transplantations (LTs) in Japan, 10 LT facilities are accredited and good outcomes have been reported. A database review was conducted to clarify the impact of case volume at LT facilities in Japan on short- and long-term outcomes. Methods: All cadaveric LT cases treated between 2000 and 2021 in Japan were analyzed using the database of the Japanese Society of Lung and Heart-Lung Transplantation (JSLHT). The nine institutions represented were categorized into the low-volume (LV; <80 cumulative LT cases, <8 LTs/year, n=5) and high-volume (HV; ≥80 cumulative LT cases, ≥8 LTs/year, n=4) centers. Ninety-day and 1-year mortality, as well as 5- and 10-year survival data were evaluated. Results: A total of 658 cadaveric LTs were performed at the nine institutions. The 90-day rates of mortality at the HV and LV centers were 3.5% and 3.9%, respectively (P=0.801), while the 1-year mortality rates were 9.2% and 11.5%, respectively (P=0.199). Additionally, log-rank analysis of Kaplan-Meier curves showing case volume did not reveal a significant difference in long-term survival between the HV and LV centers (P=0.272), though the LV centers had wide differences for long-term outcomes (P=0.030). Conclusions: Case volume did not have effects on short- or long-term outcomes following LT in Japan, while there were large variations in long-term outcomes among the LV centers compared to those of the HV centers.

Impact of Flagging/Risk Stratification System on Complications in Hospitalist Hip Fracture Co-management: Retrospective Cohort Study.

Purpose: Hip fractures are associated with high morbidity and mortality, the rates of which can be improved by comprehensive care. To improve hospitalist co-management of hip fractures, we designed and implemented hip fracture template (HFT), a flagging and risk stratification algorithm system. It includes consideration of perioperative management and preventative measures against hip fractures. We examined its effect on morbidity in patients with hip fractures and the factors associated with complications. Methods: We conducted a retrospective cohort study of patients who underwent surgery for hip fracture. The primary outcome was the perioperative complication rate, comparing patients managed with and without HFT. Multivariate analysis was adjusted for age, gender, and any significant variables shown in univariate analysis. Results: HFT was used in 121 patients and not used in 147 patients. In univariate analysis, patients were less likely to have complications if HFT was used (19.0% vs. 29.9%, P = 0.047), but there was no difference in length of stay (17 days vs. 17 days, P = 0.27) or in-hospital-mortality (0.8% vs. 0.7%, P = 1.00) between the groups. In adjusted analysis, patients managed by HFT had lower likelihood of complications (OR 0.55, 95% CI 0.31-0.98). Among patients managed by HFT, those with revised cardiac risk index (RCRI) ≥ 1 were more likely to have complications in both univariate (42.1% vs. 14.7%, P = 0.01) and adjusted analysis (OR 3.37, 95% CI 1.03-10.84). Conclusion: Patients with hip fractures managed with HFT were less likely to have complications, especially those with RCRI ≥ 1, suggesting benefits of using HFT.

Longitudinal associations between response-style strategies and abnormal eating behaviors/attitudes in adolescents: a cross-lagged panel model.

BACKGROUND: Previous studies have suggested that response-style strategies (rumination, problem-solving, and distraction) can be risk or protective factors for the development of abnormal eating behaviors/attitudes (AEB) during adolescence. However, due to limited empirical data regarding the prospective effects of these strategies on AEB, further research is needed to clarify their role in developing AEB in adolescence. METHODS: This study investigated the one-year lagged effects of response-style strategies on AEB in 24,883 fourth- to eighth-grade students in Japan between 2015 and 2019 using a cross-lagged panel model. Depressive symptoms and body mass index (BMI), which are reported to relate to AEB, were also included in the analytic model. The students self-reported their levels of response-style strategies, AEB, and depressive symptoms. We also evaluated BMI based on teachers' reports. RESULTS: We found that greater rumination significantly predicted more severe AEB in the following year among students from all grades, with small to moderate effect sizes. In addition, distraction significantly predicted more severe binge eating/purging behaviors, but with very weak small effect sizes. Problem-solving did not predict any level of AEB. Furthermore, we observed significant reciprocal relationships between response-style strategies, AEB, and depressive symptoms. Positive reciprocal associations between BMI and AEB were also found except for some intervals. CONCLUSIONS: We concluded that a decrease in rumination is critical to alleviating mental health problems, such as AEB and depressive symptoms, during adolescence. This suggests that interventions to reduce the level of rumination should be conducted in the early stages of adolescence. TRIAL REGISTRATION NUMBER: Not Applicable.

This study examines the effects of three response styles when faced with distress­rumination, problem-solving, and distraction­on unhealthy eating behaviors. In this study, we looked at how these coping strategies are linked to unhealthy eating behaviors in 24,883 students in grades four to eight in Japan between 2015 and 2019. We checked again at year-long intervals to see if the coping strategies had any effect on the students' unhealthy eating behaviors. In addition, we considered depressive symptoms and body mass index in our analysis because these variables might also be related to unhealthy eating behaviors. We found that more rumination (i.e., a repetitive negative thinking pattern) predicted the severity of unhealthy eating behaviors and depressive symptoms in the following year across all the grades. In addition, greater depressive symptoms also contributed to an increase in unhealthy eating behaviors in the following year. Therefore, we suggest that rumination is a key factor that influences mental health during adolescence.

Immunotherapy that leverages HPV-specific immune responses for precancer lesions of cervical cancer.

Cervical cancer and its precursor lesion, cervical intraepithelial neoplasia (CIN), are caused by high-risk human papillomavirus (HPV) viral infection and are highly susceptible to host immunity targeting of HPV viral proteins, which include both foreign antigens and cancer antigens expressed by tumors. Immunotherapy that induces Th1 immunoreactivity against viral proteins is expected to take advantage of this immunological regression mechanism. However, although cancer immunotherapies for cervical cancer and CIN have been developed over the past several decades, none have been commercialized. Most of these immunotherapies target the viral cancer proteins E6 and E7, which are generally the same. The reasons for the underdevelopment of HPV-targeted immunotherapy differ depending on whether the target is invasive cancer or CIN. We here summarize the developmental history of cancer immunotherapy for CIN and discuss strategies for solving the problems that led to this underdevelopment. We note that CIN is a mucosal lesion and propose that inducing mucosal immunity may be the key.

[Considerations for Perioperative Management of Patients with Complicated Respiratory Dysfunction].

This article describes the perioperative complications, perioperative risk assessment, and perioperative management of patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease, especially idiopathic pulmonary fibrosis( IPF), which are the leading diseases in respiratory dysfunction. In COPD, testing for forced expiratory volume during the first second and pulmonary diffusing capacity is important and an algorithm for testing has been presented by the Japanese Association for Chest Surgery. Acute exacerbation of IPF is the leading cause of postoperative mortality in Japan, and risk factors are being analyzed. To reduce the occurrence of postoperative complications, it is important to carry out a risk assessment, select appropriate surgical strategy, and implement a well-planned perioperative management.

X -linked inheritance of primary ciliary dyskinesia and retinitis pigmentosa due to RPGR variant: A case report and literature review.

Bronchiectasis is a chronic respiratory condition characterized by irreversible bronchial dilation, often caused by infection or inflammation. It can be associated with primary ciliary dyskinesia (PCD), a hereditary disorder affecting cilia function in various organs and flagella. PCD's genetic heterogeneity leads to varying disease severity. PCD may be more prevalent in Asia, but its diagnosis is often delayed in Japan. This study reviewed a case of PCD and retinitis pigmentosa (RP) with the relevant literature. The patient had a persistent cough, sputum, and diffuse bronchiectasis. He was diagnosed with a combination of PCD and RP, with the presence of an X-linked retinitis pigmentosa GTPase regulator (RPGR) variant confirmed through electron microscopy, retinal scan, and genetic testing. Although co-occurrence of bronchiectasis and RP is rare, PCD should be considered in cases of persistent wet cough in childhood or unidentified bronchiectasis aetiology. Ophthalmologists should consider concomitant PCD in RP patients.

Phase I and II randomized clinical trial of an oral therapeutic vaccine targeting human papillomavirus for treatment of cervical intraepithelial neoplasia 2 and 3.

BACKGROUND: Although many human papillomavirus (HPV)-targeted therapeutic vaccines have been examined for efficacy in clinical trials, none have been translated into clinical use. These previous agents were mostly administered by intramuscular or subcutaneous injection to induce systemic immunity. We investigated the safety and therapeutic efficacy of an HPV-16 E7-expressing lacticaseibacillus-based oral vaccine. METHODS: In a double-blind, placebo-controlled, randomized trial, a total of 165 patients with HPV-16-positive high-grade cervical intraepithelial neoplasia 2 and 3 were assigned to orally administered placebo or low, intermediate, or high doses of IGMKK16E7 (lacticaseibacillus paracasei expressing cell surface, full-length HPV-16 E7). In the 4 groups, IGMKK16E7 or placebo was administered orally at weeks 1, 2, 4, and 8 postenrollment. The primary outcomes included histopathological regression and IGMKK16E7 safety. RESULTS: In per-protocol analyses, histopathological regression to normal (complete response) occurred in 13 (31.7%) of 41 high-dose recipients and in 5 (12.5%) of 40 placebo recipients (rate difference = 19.2, 95% confidence interval [CI] = 0.5 to 37.8). In patients positive for HPV-16 only, the clinical response rate was 40.0% (12 of 30) in high-dose recipients and 11.5% (3 of 26) in recipients of placebo (rate difference = 28.5, 95% CI = 4.3 to 50.0). There was no difference in adverse events that occurred in the high-dose and placebo groups (P = .83). The number of HPV-16 E7-specific interferon-γ producing cells within peripheral blood increased with level of response (stable disease, partial, and complete responses; P = .004). The regression to normal (complete response) rates among recipients with high levels of immune response were increased in a dose-dependent manner. CONCLUSION: This trial demonstrates safety of IGMKK16E7 and its efficacy against HPV-16-positive cervical intraepithelial neoplasia 2 and 3. IGMKK16E7 is the first oral immunotherapeutic vaccine to show antineoplastic effects. TRIAL REGISTRATION: jRCT2031190034.

Immune-mediated Necrotizing Myopathy in a Patient with Microscopic Polyangiitis: A Case Report.

We herein report a case of immune-mediated necrotizing myopathy (IMNM) in a patient with microscopic polyangiitis (MPA). A 77-year-old Japanese woman presented with a 2-day history of proximal muscle weakness and myalgia, with elevated serum creatinine kinase (CK) levels. Findings of a muscle biopsy were compatible with IMNM; however, anti-SRP and anti-HMGCR antibodies were negative. She also had peripheral neuropathy with elevated serum MPO-ANCA titers, leading to a diagnosis of MPA. IMNM can be a pathological result of MPA muscle involvement.

Long-term Survival after Treatment of Synchronous Isolated Right External Iliac Lymph Node Metastasis from Ascending Colon Cancer: A Case Report.

BACKGROUND: Synchronous isolated external iliac lymph node metastasis of ascending colon cancer is extremely rare, and its treatment strategy has not been established. In this report, we present a case of long-term survival after surgical resection and adjuvant chemotherapy for ascending colon cancer with synchronous isolated right external iliac lymph node metastasis. CLINICAL CASE: A 65-year-old woman with anorexia and anemia was referred to our hospital. Colonoscopy and computed tomography revealed a three-quarter circumferential type 2 tumor from the cecum to the ascending colon, along with regional and right external iliac lymph node swelling. We diagnosed ascending colon cancer with right external iliac artery lymph node metastasis. An open right hemicolectomy with D3 and right external iliac lymph node dissections were performed. Results of histopathological examination showed that both lymph nodes were metastasized from ascending colon cancer. The patient received eight courses of capecitabine and oxaliplatin therapy as adjuvant chemotherapy. At 60 months after surgery, the woman has not had a recurrence. CONCLUSIONS: Surgical resection and adjuvant chemotherapy may be an effective treatment strategy for synchronous isolated right external iliac lymph node metastases from ascending colon cancer.

1-Oleoyl-lysophosphatidylethanolamine stimulates RORγt activity in TH17 cells.

Metabolic fluxes involving fatty acid biosynthesis play essential roles in controlling the differentiation of T helper 17 (TH17) cells. However, the exact enzymes and lipid metabolites involved, as well as their link to promoting the core gene transcriptional signature required for the differentiation of TH17 cells, remain largely unknown. From a pooled CRISPR-based screen and unbiased lipidomics analyses, we identified that 1-oleoyl-lysophosphatidylethanolamine could act as a lipid modulator of retinoid-related orphan receptor gamma t (RORγt) activity in TH17 cells. In addition, we specified five enzymes, including Gpam, Gpat3, Lplat1, Pla2g12a, and Scd2, suggestive of the requirement of glycerophospholipids with monounsaturated fatty acids being required for the transcription of Il17a. 1-Oleoyl-lysophosphatidylethanolamine was reduced in Pla2g12a-deficient TH17 cells, leading to the abolition of interleukin-17 (IL-17) production and disruption to the core transcriptional program required for the differentiation of TH17 cells. Furthermore, mice with T cell-specific deficiency of Pla2g12a failed to develop disease in an experimental autoimmune encephalomyelitis model of multiple sclerosis. Thus, our data indicate that 1-oleoyl-lysophosphatidylethanolamine is a lipid metabolite that promotes RORγt-induced TH17 cell differentiation and the pathogenicity of TH17 cells.

[Robot-assisted Minimally Invasive Surgery for Mediastinal Tumors].

The subxiphoid approach in thymectomy provides better visibility around the left brachiocephalic vein than the lateral thoracic approach. Robot-assisted thoracoscopic surgery is easier to parform than video- assisted thoracoscopic surgery for surgery of the upper mediastinum, because the forceps can be moved with many joints. Robot-assisted thymectomy using the subxiphoid approach may be less traumatic and less invasive than median sternotomy. We must continue to devise surgical procedures to make oncologically curative surgery more minimally invasive.

Penetrating Trauma-Induced Perilymphatic Fistula: A Case Report and Literature Review.

This article highlights the importance of early identification and surgical treatment for extremely rare traumatic perilymphatic fistula (TPF) caused by an earpick, which can pose the risk of irreversible hearing loss. Herein, we have described two cases of TPF and reviewed the literature primarily based on surgical treatment for penetrating ear trauma-induced TPF.  We highlight the case of two females who sustained an accidental penetrating injury in the ear caused by the introduction of an earpick, leading to hearing loss and dizziness. Pure tone audiometry detected elevation of the bone-conduction thresholds. Computed tomography of Labyrinth revealed pneumolabyrinth in one case. Both patients underwent exploratory surgery, we completely repositioned the stapes that had invaginated into the vestibule in one case, in the other case, we reconnected the disarticulated incudostapedial joint and sealed perilymph fistula caused by rupture of the oval window. Both patients achieved hearing improvement and complete relief from the vestibular symptoms. The literature review indicated that a scar on the posterior aspect of the tympanic membrane was found in 44.4% of cases. Hearing improvement was observed in 45.5% and 25.0% of cases with invagination of stapes and fractured footplates by fistula repair, respectively. In terms of handling stapes dislocation, the hearing improvement rate was better in cases of complete stapes repositioning (66.7%) than those of complete or partial stapes removal (16.7%). Preoperative mild bone-conduction hearing loss or localized pneumolabyrinth are favorable factors for satisfactory hearing. When surgery is performed within 11 days of the injury, satisfactory hearing improvement can be expected.

Lipid metabolism in Th17 cell function.

Among the subset of T helper cells, Th17 cells are known to play a crucial role in the pathogenesis of various autoimmune disorders, such as psoriasis, rheumatoid arthritis, inflammatory bowel disease, steroid-resistant asthma, and multiple sclerosis. The master transcription factor retinoid-related orphan receptor gamma t (RORγt), a nuclear hormone receptor, plays a vital role in inducing Th17-cell differentiation. Recent findings suggest that metabolic control is critical for Th17-cell differentiation, particularly through the engagement of de novo lipid biosynthesis. Inhibition of lipid biosynthesis, either through the use of pharmacological inhibitors or by the deficiency of related enzymes in CD4+ T cells, results in significant suppression of Th17-cell differentiation. Mechanistic studies indicate that metabolic fluxes through both the fatty acid and cholesterol biosynthetic pathways are essential for controlling RORγt activity through the generation of a lipid ligand of RORγt. This review highlights recent findings that underscore the significant role of lipid metabolism in the differentiation and function of Th17 cells, as well as elucidating the distinctive molecular pathways that drive the activation of RORγt by cellular lipid metabolism. We further elaborate on a pioneering therapeutic approach for ameliorating autoimmune disorders via the inhibition of RORγt.

Management of nontuberculous mycobacteria in lung transplant cases: an international Delphi study.

Rationale: Nontuberculous mycobacterial (NTM) diseases are difficult-to-treat infections, especially in lung transplant (LTx) candidates. Currently, there is a paucity of recommendations on the management of NTM infections in LTx, focusing on Mycobacterium avium complex (MAC), M. abscessus and M. kansasii. Methods: Pulmonologists, infectious disease specialists, LTx surgeons and Delphi experts with expertise in NTM were recruited. A patient representative was also invited. Three questionnaires comprising questions with multiple response statements were distributed to panellists. Delphi methodology with a Likert scale of 11 points (5 to -5) was applied to define the agreement between experts. Responses from the first two questionnaires were collated to develop a final questionnaire. The consensus was described as a median rating >4 or <-4 indicating for or against the given statement. After the last round of questionnaires, a cumulative report was generated. Results: Panellists recommend performing sputum cultures and a chest computed tomography scan for NTM screening in LTx candidates. Panellists recommend against absolute contraindication to LTx even with multiple positive sputum cultures for MAC, M. abscessus or M. kansasii. Panellists recommend MAC patients on antimicrobial treatment and culture negative can be listed for LTx without further delay. Panellists recommend 6 months of culture-negative for M. kansasii, but 12 months of further treatment from the time of culture-negative for M. abscessus before listing for LTx. Conclusion: This NTM LTx study consensus statement provides essential recommendations for NTM management in LTx and can be utilised as an expert opinion while awaiting evidence-based contributions.

Association of frequent hypermethylation with high grade histological subtype in lung adenocarcinoma.

Lung adenocarcinoma is classified morphologically into five histological subtypes according to the WHO classification. While each histological subtype correlates with a distinct prognosis, the molecular basis has not been fully elucidated. Here we conducted DNA methylation analysis of 30 lung adenocarcinoma cases annotated with the predominant histological subtypes and three normal lung cases using the Infinium BeadChip. Unsupervised hierarchical clustering analysis revealed three subgroups with different methylation levels: high-, intermediate-, and low-methylation epigenotypes (HME, IME, and LME). Micropapillary pattern (MPP)-predominant cases and those with MPP components were significantly enriched in HME (p = 0.02 and p = 0.03, respectively). HME cases showed a significantly poor prognosis for recurrence-free survival (p < 0.001) and overall survival (p = 0.006). We identified 365 HME marker genes specifically hypermethylated in HME cases with enrichment of "cell morphogenesis" related genes; 305 IME marker genes hypermethylated in HME and IME, but not in LME, with enrichment "embryonic organ morphogenesis"-related genes; 257 Common marker genes hypermethylated commonly in all cancer cases, with enrichment of "regionalization"-related genes. We extracted surrogate markers for each epigenotype and designed pyrosequencing primers for five HME markers (TCERG1L, CXCL12, FAM181B, HOXA11, GAD2), three IME markers (TBX18, ZNF154, NWD2) and three Common markers (SCT, GJD2, BARHL2). DNA methylation profiling using Infinium data was validated by pyrosequencing, and HME cases defined by pyrosequencing results also showed the worse recurrence-free survival. In conclusion, lung adenocarcinomas are stratified into subtypes with distinct DNA methylation levels, and the high-methylation subtype correlated with MPP-predominant cases and those with MPP components and showed a poor prognosis.

M2 tumor-associated macrophages resist to oxidative stress through heme oxygenase-1 in the colorectal cancer tumor microenvironment.

M2 tumor-associated macrophages (M2-TAMs) promote cancer cell proliferation and metastasis in the TME. Our study aimed to elucidate the mechanism of increased frequency of M2-TAMs infiltration in the colorectal cancer (CRC)-TME, focusing on the resistance to oxidative stress through nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. In this study, we evaluated the correlation between M2-TAM signature and mRNA expression of antioxidant related genes using public datasets, and the expression level of antioxidants in M2-TAMs by flow cytometry and the prevalence of M2-TAMs expressing antioxidants by immunofluorescence staining using surgically resected specimens of CRC (n = 34). Moreover, we generated M0 and M2 macrophages from peripheral blood monocytes and evaluated their resistance to oxidative stress using the in vitro viability assay. Analysis of GSE33113, GSE39582, and The Cancer Genome Atlas (TCGA) datasets indicated that mRNA expression of HMOX1 (heme oxygenase-1 (HO-1)) was significantly positively correlated with M2-TAM signature (r = 0.5283, r = 0.5826, r = 0.5833, respectively). The expression level of both Nrf2 and HO-1 significantly increased in M2-TAMs compared to M1- and M1/M2-TAMs in the tumor margin, and the number of Nrf2+ or HO-1+M2-TAMs in the tumor stroma significantly increased more than those in the normal mucosa stroma. Finally, generated M2 macrophages expressing HO-1 significantly resisted to oxidative stress induced by H2O2 in comparison with generated M0 macrophages. Taken together, our results suggested that an increased frequency of M2-TAMs infiltration in the CRC-TME is related to Nrf2-HO-1 axis mediated resistance to oxidative stress.