Keratin 6A is expressed at the invasive front and enhances the progression of colorectal cancer.

Keratins are intermediate filament proteins in epithelial cells, and they are important for cytoskeletal organization. Keratin 6A (KRT6A), classified as a type II keratin, is normally expressed in stratified squamous epithelium and squamous cell carcinomas. Little is known about the expression and role of KRT6A in adenocarcinomas. We investigated the clinicopathological and molecular biological significance of KRT6A in colorectal adenocarcinoma. Immunostaining of our institution's colorectal adenocarcinoma cases demonstrated that KRT6A showed significantly stronger expression at the invasive front than the tumor center (p < 0.0001). The high-KRT6A-expression cases (n = 47) tended to have a high budding grade associated with significantly worse prognoses. A multivariate analysis revealed that the KRT6A expression status was an independent prognostic factor for overall survival (p = 0.0004), disease-specific survival (p = 0.0097) and progression-free survival (p = 0.0033). The correlation between KRT6A and patient prognoses was also validated in an external cohort from a published dataset. To determine the function of KRT6A in vitro, KRT6A was over-expressed in three colon cancer cell lines, DLD-1, SW620, and HCT 116. KRT6A overexpression increased migration and invasion in DLD-1, but did not in SW620 and HCT116. In three-dimensional sphere-forming culture, KRT6A expression enhanced the irregular protrusion around the spheroid in DLD-1. Our findings in the present study indicated that KRT6A expression is a valuable prognostic marker of colorectal cancer and KRT6A may be involved the molecular mechanism in the progression of invasive areas of colorectal cancer.

A case of rectal metastasis of prostate cancer mimicking extramural growth-type rectal tumor.

Rectal metastases of prostate cancer are rare and may be difficult to diagnose. In this report, we describe a case in which an extramural growth-type rectal tumor was resected and pathologically diagnosed as prostate cancer metastasis. A 70-year-old man on hormone therapy for prostate cancer with seminal vesicle invasion and pelvic lymph node metastasis was referred to our department after an imaging scan showed an extramural growth-type rectal tumor. Endoscopic ultrasound-guided fine needle aspiration was considered for diagnosis, but the patient preferred an early resection without the exam, so surgery was performed. Histopathological examination revealed that the lesion was in the adventitia of the rectum and metastasis of prostate cancer. Metastatic lesions of prostate cancer are not indicated for resection. A detailed preoperative study with the possibility of prostate cancer metastasis in mind is necessary because it is relevant to choosing the treatment strategy.

CT-derived skeletal muscle change before immunotherapy predicts survival of advanced gastric cancer: associations with inflammatory markers and liver lipid metabolism.

BACKGROUND: Skeletal muscle (SM) is a key factor in cancer treatment. However, it is unclear whether pretreatment SM change affects the outcome of immune checkpoint inhibitors (ICIs) therapy in gastric cancer (GC). METHODS: Advanced GCs treated with ICIs were retrospectively investigated. SM evaluated by psoas muscle area at the third lumbar vertebra was measured on CT acquired within 1 month from the start of ICIs therapy (CT-1), and on CT acquired 2.8 ± 0.84 months before CT-1. Monthly change rate of SM (MCR-SM) was defined as the change rate of SMs between those two CTs divided by the period between those CTs (month). Monthly change rate of body weight (MCR-BW) during the same period was also calculated. They were compared with disease-specific survival (DSS) and progression-free survival (PFS). MCR-SM was compared with pretreatment markers including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), C-reactive protein (CRP), and liver-to-spleen CT attenuation ratio (LSR) as a marker of liver lipid metabolism. RESULTS: This study enrolled eighty-three GC patients. MCR-SM significantly correlated with DSS and PFS (P < 0.0001, 0.001, respectively), whereas MCR-BW did not. Kaplan-Meier analyses demonstrated that higher MCR-SM (MCR-SM ≥ -0.7185%) significantly associated with better DSS and PFS (P = 0.0002, 0.03, respectively). Patients with positive MCR-SM showed significantly lower NLR, MLR, and CRP than those with negative (P = 0.01, 0.006, 0.003, respectively). MCR-SM showed a significant positive correlation with LSR (P = 0.007, R = 0.30). CONCLUSIONS: Pretreatment SM loss, associated with high systemic inflammation and hepatic fat accumulation, related to poor outcome of ICIs therapy in GC.

Intraoperative assessment of blood flow using transabdominal ultrasound during laparoscopic surgery of celiac artery compression syndrome.

Surgical treatment of celiac artery (CA) compression syndrome (CACS) is to release the median arcuate ligament (MAL) by removing the abdominal nerve plexus surrounding CA. In laparoscopic surgery of CACS, objective intraoperative assessment of blood flow in CA is highly desirable. We herein demonstrate a case of laparoscopic surgery of CACS with use of intraoperative transabdominal ultrasound. A 52-year-old woman was presented with epigastric pain and vomiting after eating. Contrast-enhanced computed tomography demonstrated significant stenosis at the origin of CA. Doppler study of CA was also performed, and she was diagnosed as CACS. Laparoscopic surgery was performed, and the MAL was divided. And then, Doppler study using intraoperative transabdominal ultrasound confirmed the successful decompression of CA. This patient was discharged on postoperative day 11, and her symptoms was improved. Intraoperative assessment of blood flow in CA using transabdominal ultrasound was a simple and useful method for laparoscopic surgery of CACS.

A case of laparoscopic revision surgery 30 years after vertical banded gastroplasty for morbid obesity.

As the number of bariatric and metabolic surgeries being performed is increasing, the importance of revision surgeries is escalating. In this report, we describe a case of revision surgery performed 30 years after vertical banded gastroplasty (VBG), including a review of the surgical techniques. The patient was a male in his 50s who had previously undergone VBG for morbid obesity (body mass index of 72.6 kg/m2 ), resulting in gradual weight loss. Twenty-eight years later, reflux symptoms due to stenosis of the mesh area developed. Despite conservative treatment, the symptoms recurred, and aspiration pneumonia developed. Gastrojejunal and Y-anastomoses were performed laparoscopically. Postoperatively, the patient progressed well with no weight regain. In revision surgery, it is essential to accurately assess the patient's pathophysiology, as the surgical technique must consider improvement in symptoms, risk of weight regain, and the need for observation of the residual stomach.

Novel Advances in Qualitative Diagnostic Imaging for Decision Making in Multidisciplinary Treatment for Advanced Esophageal Cancer.

Background: Recently, neoadjuvant therapy and the succeeding surgery for advanced esophageal cancer have been evaluated. In particular, the response to the therapy has been found to affect surgical outcomes, and thus a precise evaluation of treatment effect is important for this strategy. In this study, articles on qualitative diagnostic modalities to evaluate tumor activities were reviewed, and the diagnostic indices were examined. Methods: For prediction of the effect, perfusion CT and diffusion MRI were estimated. For the histological response evaluation, perfusion CT, diffusion-MRI, and FDG-PET were estimated. For downstaging evaluation of T4, tissue-selective image reconstruction using enhanced CT was estimated and diagnostic indices were reviewed. Results: The prediction of the effect using perfusion CT with 'pre CRT blood flow' and diffusion MRI with 'pre CRT ADC value'; the estimation of the histological response using perfusion CT with 'post CRT blood flow reduction, using diffusion MRI with 'post CRT ADC increasing', and using FDG-PET with 'post CRT SUV reduction'; and the downstaging evaluation of T4 using CT image reconstruction with 'fibrous changed layer' were performed well, respectively. Conclusions: Qualitative imaging modalities for prediction or response evaluation of neoadjuvant therapy for progressive esophageal cancer were useful for the decision making of the treatment strategy of the multidisciplinary treatment.

Use of inducible and limiting fluorescence in laparoscopic endoscopic cooperative surgery.

Video 1Demonstration of the special use of the near-infrared fluorescent clip in laparoscopic endoscopic cooperative surgery.

Peripherally inserted central catheter securement with cyanoacrylate glue and bloodstream infection: A retrospective cohort study.

BACKGROUND: Treatment via a peripherally inserted central venous catheter is important for anticancer treatment, perioperative management, and nutrition management. In this study, we aimed to investigate the usefulness of cyanoacrylate glue (CG) in managing peripherally inserted central venous catheters in adults. METHODS: This retrospective cohort study enrolled 411 adults requiring a central venous catheter for treatment in the Chiba University Esophageal-Gastro-Intestinal Surgery department between January 2021 and October 2022. The preventive effect of CG in reducing adverse events, including infection, tip migration, and thrombus formation, was evaluated by reviewing electronic medical records, chest radiographs, and contrast-enhanced computed tomography scans. RESULTS: CG and other dressings were used in 158 (CG group) and 253 (control group) patients, respectively. The incidence of catheter infection based on the clinical course was lower in the CG group (3.2%) than in the control group (9.1%; P = 0.03). However, cases of infection confirmed by blood or catheter cultures did not differ between the CG (1.3%) and control (1.9%) groups (P = 1.0). Chest radiographs revealed that catheter tip migration (mean ± SD) was lesser in the CG group (8.2 ± 6.7 mm) than in the control group (15.0 ± 15.8 mm; P < 0.01). There were two cases of venous thrombus formation in the control group. CONCLUSION: In a population dominated by esophago-gastroenterological malignancy, peripherally inserted central catheter securement via CG was associated with decreased catheter removal because of suspected catheter infection. Further research on larger cohorts is needed to determine if other adverse events decrease following peripherally inserted central catheter securement via CG.

The Link of mRNA and rRNA Transcription by PUF60/FIR through TFIIH/P62 as a Novel Therapeutic Target for Cancer.

The interaction between mRNA and ribosomal RNA (rRNA) transcription in cancer remains unclear. RNAP I and II possess a common N-terminal tail (NTT), RNA polymerase subunit RPB6, which interacts with P62 of transcription factor (TF) IIH, and is a common target for the link between mRNA and rRNA transcription. The mRNAs and rRNAs affected by FUBP1-interacting repressor (FIR) were assessed via RNA sequencing and qRT-PCR analysis. An FIR, a c-myc transcriptional repressor, and its splicing form FIRΔexon2 were examined to interact with P62. Protein interaction was investigated via isothermal titration calorimetry measurements. FIR was found to contain a highly conserved region homologous to RPB6 that interacts with P62. FIRΔexon2 competed with FIR for P62 binding and coactivated transcription of mRNAs and rRNAs. Low-molecular-weight chemical compounds that bind to FIR and FIRΔexon2 were screened for cancer treatment. A low-molecular-weight chemical, BK697, which interacts with FIRΔexon2, inhibited tumor cell growth with rRNA suppression. In this study, a novel coactivation pathway for cancer-related mRNA and rRNA transcription through TFIIH/P62 by FIRΔexon2 was proposed. Direct evidence in X-ray crystallography is required in further studies to show the conformational difference between FIR and FIRΔexon2 that affects the P62-RBP6 interaction.

Combinational antibody detection approach increases the clinical validity of colorectal cancer screening.

BACKGROUND: At different stages of the disease, biomarkers can help to determine disease progression and recurrence and provide a personalized indicator of therapeutic effectiveness. The serological identification of antigens by recombinant cDNA expression cloning (SEREX) has identified five SEREX antigens. RESULTS: Compared with healthy donors, anti-FIRΔexon2 and anti-SOHLH antibodies (Abs) in the sera of patients with colorectal cancer (CRC) were markedly higher. Furthermore, no correlation was noted between five SEREX antigens and the three tumor markers (CEA, CA19-9, and anti-p53 Abs), indicating that anti-FIRΔexon2 Abs are an independent candidate marker for patients with CRC. Generally, the levels of anti-FIRΔexon2 Abs combined with clinically available tumor markers were determined to be significantly higher compared with CEA, CA19-9. Moreover, in early-stage CRC, the levels of anti-FIRΔexon2 Abs combined with existing tumor markers were higher than those of CEA, CA19-9. CONCLUSION: Due to the highly heterogeneous nature of CRC, a single tumor marker is unlikely to become a standalone diagnostic test due to its commonly insufficient sensitivity and/or specificity. Using a combination antibody detection approach of tumor markers for CRC diagnosis has the potential to be an effective approach. Therefore, the use of serum protein biomarker candidates holds promise for the development of inexpensive, noninvasive, and inexpensive tests for the detection of CRC.

Inflammatory and Nutritional Indices as Prognostic Markers in Elderly Patients With Gastric Cancer.

BACKGROUND/AIM: Peripheral blood inflammatory and nutritional indices are independent prognostic factors for various cancers. However, as society's longevity and the demand for surgery in the elderly increase, it remains unclear whether these indices are valuable for patients aged ≥80 years. This study aimed to assess the utility of peripheral blood indices as prognostic markers in elderly patients with gastric cancer (GC). PATIENTS AND METHODS: This study included 103 elderly patients (aged ≥80 years) who underwent radical gastrectomy at our hospital between 2008 and 2020. Preoperative systemic inflammatory and nutritional indices, including the neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), and prognostic and nutritional index (PNI), were evaluated. Prognostic evaluation was performed using Kaplan-Meier analysis and Cox regression. RESULTS: There were no statistically significant differences in NLR, PLR, and LMR regarding overall survival (OS) and relapse-free survival (RFS). However, patients with low PNI had a markedly worse prognosis (3-year OS: 63.9% vs. 81.2%, p=0.002; 3-year RFS: 55.3% vs. 77.6%, p=0.002). Multivariate analysis revealed that male sex and low PNI were independent predictors of OS (p=0.007p=0.003, respectively) and RFS, with only PNI showing significance (p=0.023). CONCLUSION: Preoperative PNI is an independent prognostic factor for survival in elderly patients with GC who undergo radical gastrectomy.

[A Case of Long-Term Survival without Recurrence after Completion of Immunotherapy Due to Response of Third- Line Nivolumab for Liver Metastasis Recurrence of Esophagogastric Junction Cancer].

The patient was a 66-year-old man with dysphagia. He underwent total gastrectomy and trans-hiatal abdominal esophagectomy with lymph node dissection, including the inferior mediastinum, for esophagogastric junction cancer. The postoperative pathological examination revealed poorly differentiated adenocarcinoma T4aN2, Stage ⅢA, HER2 negative, and postoperative adjuvant therapy S-1 oral administration was started. Four months after surgery, computed tomography (CT)showed recurrent liver and para-aortic lymph node metastases. First-line XELOX therapy and second-line weekly PTX therapy resulted in PD, and nivolumab administration was started as third-line. The evaluation was PR and CR at 3 and 6 months, respectively. At the same time, he developed acute cholangitis and underwent open lithotripsy drainage. Postoperatively, treatment was terminated according to the patient's wishes. To date, it has been 5 years since the first operation and 3 and a half years since remission with nivolumab, and no recurrence has been observed. There is little evidence regarding the timing of conversion or treatment discontinuation for successful cases of immunotherapy in the salvage line for gastric cancer.

Small bowel adenocarcinomas with favorable prognoses by radical resection and adjuvant chemotherapy: a case series of five cases.

BACKGROUND: Small bowel cancer is very rare, accounting for less than 5% of all gastrointestinal cancers, and small bowel adenocarcinoma accounts for approximately 40% of all small bowel cancers. Small bowel adenocarcinoma is often found in advanced stages, with only 40-65% of cases being curatively resectable. The prognosis is poor, with a 5-year survival rate of 14-33% for all patients and 40-60% for those who are curatively resectable. In Japan, practice guidelines for duodenal cancer were instituted in 2021. However, evidence-based standard treatments have not been established for jejunal and ileal cancers. In particular, chemotherapeutic options are limited, and there are only a few reports on multidisciplinary treatments, including adjuvant chemotherapy. CASE PRESENTATION: We report five cases of jejunal or ileal lesions that were treated with adjuvant chemotherapy after radical resection. Three patients were male and two were female, with a median age of 67 years. Tumor localization was observed in the jejunum in all cases. Clinical staging was as follows: stage IIIA in two cases and stage IIIB in three cases. Laparotomy was then performed in all cases, employing partial resection with lymph node dissection. Pathological staging in all cases was as follows: stage IIB in two cases, stage IIIA in one case, and stage IIIB in two cases. In all cases, the regimen for adjuvant chemotherapy was selected based on the colorectal cancer guidelines. No serious complications arose from adjuvant therapy; however, adverse events occurred in patients receiving multi-agent chemotherapy. No recurrence was observed in any of the cases, and all the patients survived, with a median survival time of 32 months. As a representative case, we present a case of adjuvant chemotherapy for jejunal adenocarcinoma staged as pT3N2M0, pStage IIIB, with no recurrence at 32 months postoperatively. CONCLUSIONS: In general, favorable outcomes were achieved with adjuvant therapy applied in accordance with the criteria for colorectal cancer. These favorable outcomes suggest that it is necessary to identify the risk factors and indications for adjuvant therapy, specifically for small bowel adenocarcinoma.

Safety and effectiveness of metabolic surgery in older Japanese patients.

Aim: According to the current guidelines in Japan, the upper age limit for bariatric and metabolic surgery is 65 y. This study aimed to examine the appropriateness of this upper age limit. Methods: Using the database maintained by the Japanese Society for Treatment of Obesity, we conducted an analysis of patients in two age groups: those aged <65 y and those aged ≥65 y. Our analysis focused on postoperative weight loss, improvement in comorbidities, and frequency of perioperative complications. Results: A total of 2885 patients aged <65 y (mean, 43.9 ± 9.5 y) with a preoperative body mass index of 42.4 ± 8.1 kg/m2, while 56 aged ≥65 y (mean, 67.3 ± 3.2 y; maximum, 78 y) with a preoperative body mass index of 40.5 ± 6.6 kg/m2. Patients aged ≥65 y had a higher rate of dyslipidemia and hypertension. The rates of reoperation, surgical complications, and postoperative complications did not differ between the age groups. Both groups achieved significant weight loss postoperatively, and no differences in the improvement of comorbidities were noted. After adjusting the covariate balance via propensity score matching, no age-related differences in perioperative and postoperative complications were observed. Conclusion: Metabolic surgery is safe and effective for older patients with clinically severe obesity. Weight loss was less in patients aged ≥65 y, but the percentage of total weight loss did not differ between the groups.

RYBP contributes to improved prognosis in colorectal cancer via regulation of cell cycle, apoptosis and oxaliplatin sensitivity.

Ring1 and YY­1 binding protein (RYBP) is a member of the polycomb repressive complex 1 and serves as a transcriptional suppressor via epigenetic modification. RYBP has a tumour­suppressive role in solid tumours, but its function in colorectal cancer (CRC) remains unknown. The present study evaluated the expression of RYBP using immunohistochemistry in 140 cases of primary CRC and 11 patient­matched cases of liver metastases. Using CRC cell lines with different TP53 gene status such as HCT116 (TP53wt/wt), HCT116 (TP53­/­), SW48 and DLD­1 cells, proliferation, cell cycle progression and apoptosis, as well as the effect of RYBP on oxaliplatin sensitivity, were assessed. Clinical data showed that low RYBP expression was significantly associated with risk of distant metastasis and recurrence, and patients with high RYBP expression demonstrated significantly better cancer­specific and disease­free survival. In vitro experiments revealed that RYBP suppressed cell proliferation by inducing cell cycle arrest and apoptosis in TP53 wild­type cells. In addition, endogenous RYBP overexpression enhanced sensitivity to oxaliplatin. Therefore, RYBP may contribute to improved prognosis in CRC by regulating the cell cycle, apoptosis and oxaliplatin sensitivity via the p53­mediated pathway.

[A Case of Primary Duodenal Adenocarcinoma in the Third Portion Treated with Partial Duodenectomy and Adjuvant Chemotherapy].

A 69-year-old man was referred for vomiting. CT and upper gastrointestinal endoscopy revealed a circumferential stenotic lesion in the third portion of the duodenum, and partial duodenectomy and lymph node dissection were performed for the diagnosis of duodenal adenocarcinoma. The histopathological diagnosis was pT3, pN0, pStage ⅡA(UICC 8th)well differentiated tubular adenocarcinoma. The patient was treated with FOLFOX as adjuvant chemotherapy and is alive 2 years and 4 months postoperatively without recurrence. Primary duodenal adenocarcinoma in the third portion is rare, and further case experience is required for selection of the operation and adjuvant therapy.

Verification of Safety and Efficacy of Sleeve Gastrectomy Based on National Registry by Japanese Society for Treatment of Obesity.

In Japan, bariatric surgical treatment was started in 1982. The Japanese Society for Treatment of Obesity (JSTO) was established in 2007, and then, JSTO started the national registry of bariatric surgery cases and multidisciplinary educational program. A total of 44 facilities registered 4055 bariatric surgical cases until 2021. In this study, the purpose is to clarify the indication, the safety and the effectiveness of the sleeve gastrectomy using national registry database compiled by JSTO. Preoperative BMI ranged from 27.6 to 90.7 kg/m2, and the mean value was 42.7. With regard to gender, men/women was 1/1.3. Age was 42.2 as mean. As preoperative comorbidities, DM ratio was 54.4% of the patients, hypertension 64.5%, dyslipidemia 65.1%, and sleep apnea syndrome 69.8%. As an operation method, laparoscopic method was conducted in 99.7% of the cases. The intraoperative incidence rate was 0.9%. Conversion rate to open method was 1.1%. Postoperative morbidity ratio was 5.6%, and mortality was 0%. Reoperations were performed in 1.5% of the cases. Postoperative hospital stay was 5 days in median value. Body weight loss was 27.6 kg in the mean value after follow-up days of 279 ± 245. As the effect on the preoperative metabolic comorbidities, DM has improved in 82.9% of the cases, hypertension 67.9% and dyslipidemia 66.6%. In conclusion, using JSTO database, we evaluated the indication, postoperative complications and weight loss effect of sleeve gastrectomy in Japan. Regarding the evaluation of the effect on preoperative comorbidities, future follow-up based on more detailed criteria was considered to be necessary.

[A Patient with AFP-Producing Gastric Cancer and Stenosis Who Regained Oral Intake Capabilities after T-DXd Treatment].

We present the case of a 55-year-old man with HER2-positive, AFP-producing gastric cancer and multiple liver metastases. The patient consequently underwent 7 courses of SOX plus trastuzumab therapy, 3 courses of weekly PTX plus ramucirumab therapy, and 3 courses of nivolumab therapy, all of which resulted in PD. Obstruction due to tumor growth became noticeable 9 months after the start of the first treatment. Subsequently, the patient experienced malnutrition and systemic edema due to impaired oral intake. However, subsequent trastuzumab deruxtecan(T-DXd)therapy induced remarkable tumor shrinkage. Furthermore, oral intake became possible, and edema started subsiding. Thus, we report the course of a patient with AFP-producing gastric cancer and stenosis who regained oral intake capabilities after T-DXd treatment.

MicroRNAs associated with postoperative outcomes in patients with limited stage neuroendocrine carcinoma of the esophagus.

Esophageal neuroendocrine carcinoma (E-NEC) is an aggressive disease with a poor prognosis. The present study aimed to assess the role of surgery in the treatment of patients with resectable E-NEC, and identify a microRNA (miRNA/miR) signature in association with positive postoperative outcomes. Between February 2017 and August 2019, 36 patients with E-NEC who underwent curative surgery at the Japan Neuroendocrine Tumor Society partner hospitals were enrolled in the study. A total of 16 (44.4%) patients achieved disease-free survival (non-relapse group), whereas 20 (55.6%) patients developed tumor relapse (relapse group) during the median follow-up time of 36.5 months (range, 1-242) after surgery with a 5-year overall survival rate of 100 and 10.8%, respectively (P<0.01). No clinicopathological parameters, such as histological type or TNM staging, were associated with tumor relapse. Microarray analysis of 2,630 miRNAs in 11 patients with sufficient quality RNA revealed 12 miRNAs (miR-1260a, -1260b, -1246, -4284, -612, -1249-3p, -296-5p, -575, -6805-3p, -12136, -6822-5p and -4454) that were differentially expressed between the relapse (n=6) and non-relapse (n=5) groups. Furthermore, the top three miRNAs (miR-1246, -1260a and -1260b) were associated with overall survival (P<0.01). These results demonstrated that surgery-based multidisciplinary treatment is effective in a distinct subpopulation of limited stage E-NEC. A specific miRNA gene set is suggested to be associated with treatment outcome.

LIN28B promotes cell invasion and colorectal cancer metastasis via CLDN1 and NOTCH3.

The RNA-binding protein LIN28B is overexpressed in over 30% of patients with colorectal cancer (CRC) and is associated with poor prognosis. In the present study, we unraveled a potentially novel mechanism by which LIN28B regulates colonic epithelial cell-cell junctions and CRC metastasis. Using human CRC cells (DLD-1, Caco-2, and LoVo) with either knockdown or overexpression of LIN28B, we identified claudin 1 (CLDN1) tight junction protein as a direct downstream target and effector of LIN28B. RNA immunoprecipitation revealed that LIN28B directly binds to and posttranscriptionally regulates CLDN1 mRNA. Furthermore, using in vitro assays and a potentially novel murine model of metastatic CRC, we show that LIN28B-mediated CLDN1 expression enhances collective invasion, cell migration, and metastatic liver tumor formation. Bulk RNA sequencing of the metastatic liver tumors identified NOTCH3 as a downstream effector of the LIN28B/CLDN1 axis. Additionally, genetic and pharmacologic manipulation of NOTCH3 signaling revealed that NOTCH3 was necessary for invasion and metastatic liver tumor formation. In summary, our results suggest that LIN28B promotes invasion and liver metastasis of CRC by posttranscriptionally regulating CLDN1 and activating NOTCH3 signaling. This discovery offers a promising new therapeutic option for metastatic CRC to the liver, an area where therapeutic advancements have been relatively scarce.