Can underwater endoscopic mucosal resection be an alternative to conventional endoscopic mucosal resection for superficial non-ampullary duodenal epithelial tumors?

Objectives

Underwater endoscopic mucosal resection (UEMR) is a simpler procedure for superficial non-ampullary duodenal epithelial tumors (SNADET) than conventional endoscopic mucosal resection (cEMR). This study aimed to evaluate whether cEMR can be substituted by UEMR for SNADET in terms of effectiveness, safety, and learning curve.

Methods

A total of 157 consecutive patients with 203 SNADETs ≤20 mm in diameter, including 107 lesions resected by cEMR and 96 lesions resected by UEMR, between January 2019 and May 2023, were retrospectively recruited. The treatment outcomes were compared between the cEMR and UEMR groups. The risk factors for incomplete resection by UEMR were analyzed using univariate and multivariate analyses. Lesions in the UEMR group were divided chronologically into five periods; thereafter, the en bloc resection rate and procedure time were compared.

Results

No significant differences existed between the cEMR and UEMR groups in the mean procedure time (3.9 min vs. 3.6 min, p = 0.1380) or en bloc resection rate (91% vs. 94%, p = 0.4138). No perforation was observed in either group. Tumor size was an independent risk factor for incomplete resection using UEMR (p < 0.01). The history of biopsy was not associated with incomplete resection using UEMR. The en bloc resection rate of UEMR was 100% (20/20) in the first period and ranged from 90% to 100% over all periods.

Conclusion

UEMR is safe and effective for SNADET ≤20 mm, regardless of a history of biopsy, and is easy to learn. Thus, UEMR can serve as an alternative to cEMR.

Clinical outcomes of endoscopic submucosal dissection for large pedunculated colorectal carcinoma: A retrospective multicenter study

Objectives

Complete en-bloc resection of pedunculated colorectal carcinoma is necessary for a proper pathological diagnosis. However, due to poor visibility, large pedunculated colorectal carcinomas are difficult to snare and resect en-bloc using endoscopic resection or polypectomy. Additionally, the bleeding risk of large pedunculated colorectal carcinomas is relatively high. We aimed to assess the feasibility and safety of endoscopic submucosal dissection for large pedunculated colorectal carcinomas.

Methods

We conducted a retrospective multicenter cohort study to assess 36 consecutive patients with 36 large pedunculated colorectal carcinomas who underwent endoscopic submucosal dissection and evaluated the outcomes of endoscopic submucosal dissection. Furthermore, patients were divided into two groups according to the procedure time, and the factors related to the procedure time were assessed.

Results

The mean tumor size was 34.1 ± 9.9 mm. The en-bloc, complete en-bloc, and curative resection rates were 97% (35/36), 97% (35/36), and 81% (29/36), respectively. The rate of severe bleeding during the procedure was 11% (4/36); however, it could be controlled endoscopically in all patients. The rate of intraoperative perforation and delayed bleeding was 0% (0/36). Delayed perforations occurred in one patient that required surgery. A long procedure time was correlated with the location of the flexure and poor endoscope operability. No recurrence was observed in any patient. None of the patients died of colorectal carcinoma.

Conclusions

Our results showed the feasibility and safety of endoscopic submucosal dissection for large pedunculated colorectal carcinomas.

Pazopanib-induced enteritis in a patient with renal cell carcinoma

A 69-year-old woman presented to our department with the chief complaint of diarrhea. She had undergone left nephrectomy for renal cancer 14 years earlier. Three years earlier, metastasis was detected in the left retroperitoneal cavity, and pazopanib administration was initiated. In the 29th month after the start of chemotherapy, the patient developed diarrhea, and on the 31st month, computed tomography showed thickening of the intestinal wall. Colonoscopy revealed white villi, intramucosal hemorrhage in the terminal ileum, and rough inflammatory mucosa with inflammatory polyps extending from the transverse to the sigmoid colon. Suspecting pazopanib-induced enteritis, we discontinued the medication, and the diarrhea resolved within 3 days. On the 21st day after discontinuation, colonoscopy revealed that the inflammatory polyps had shrunk, and the inflammatory findings had improved. Biopsy of the white villi of the ileum revealed histiocytes. The patient resumed treatment with pazopanib at 400 mg/day and developed soft stool on the 7th day after resumption. Compared with other tyrosine-kinase inhibitor-induced enteritis cases, this case showed less bleeding and more extensive inflammatory findings. There are similarities as well as differences from cases of previously reported pazopanib-induced enteritis. The mechanisms and characteristics of this disease require further investigation.

Clinicopathological and genomic features of superficial esophageal squamous cell carcinomas in nondrinker, nonsmoker females

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is sometimes detected in non-drinker and non-smoker females who are considered to have very low risk of ESCC development in daily practice. This study examined the clinicopathological and genomic characteristics of ESCCs in females with no history of drinking and smoking.

METHODS

The sample comprised 118 ESCC lesions occurring in 95 female patients who underwent endoscopic submucosal dissection at our department between January 2008 and December 2019. The patients were categorized into two groups: 51 lesions in 49 patients with no history of drinking and smoking (nondrinker/nonsmoker [NDNS] group) and 69 lesions in 45 patients with a history of drinking or smoking (drinker/smoker [DS] group). We analyzed the differences in clinicopathological and cancerous genomic characteristics between the groups. Significant genomic alterations were validated using immunohistochemistry.

RESULTS

Multiple logistic regression revealed that older age, fewer multiple Lugol-voiding lesions (LVLs), and reflux esophagitis (RE) were independently associated with the occurrence of ESCCs in the NDNS group. ESCC lesions in the NDNS group were predominantly located in the mid-thoracic esophagus, posterior wall side, with 0-IIa, the aspect ratio of the lesion >2 (vertical/horizontal), and endoscopic keratinization. Genetic analysis showed that CDKN2A driver alterations were significantly more frequent and KMT2D alterations were significantly less frequent in the NDNS group than in the DS group. KMT2D alterations were strongly correlated with immunostaining.

CONCLUSION

Older nondrinker, nonsmoker females with RE and fewer multiple LVLs may develop longitudinal 0-IIa ESCC with keratinization of the posterior wall of the mid-thoracic esophagus. ESCCs in nondrinker, nonsmoker females had fewer KMT2D alterations and more CDKN2A alterations, which may be a biomarker for treatment.

Clinical factors associated with stable treatment of chronic constipation in Japanese patients

BACKGROUND/AIMS

Chronic constipation (CC) is one of the most common gastrointestinal disorders in the general population. Although there are many treatment options, achieving a stable treatment for CC remains one of the challenges in clinical practice. This study aimed to evaluate the clinical factors associated with stable treatment for CC in Japanese patients.

METHODS

A retrospective, cross-sectional, and multicenter study was carried out. Patients were eligible for inclusion if they fulfilled the Rome IV criteria for diagnosing CC and had been treated for at least one and a half years. Patients with up to two prescription modifications for CC in one year were defined as the stable treatment group, whereas those with three or more prescription changes were defined as the unstable treatment group. Univariate and multivariate analyses were carried out to identify factors associated with CC.

RESULTS

A total of 114 patients have been recruited. There were 82 patients (77.0%) in the stable treatment group and 32 patients (23.0%) in the unstable treatment group. Based on multivariate likelihood analysis, only using acid-suppressive drugs contributed to stability treatment in CC patients (odds ratio: 2.81, 95% confidence interval: 1.12-7.08, p = 0.03).

CONCLUSION

Administration of acid-suppressive drugs was the only factor related to the stability of CC treatment. Further studies are needed to validate the results as well as clarify the causes.

Predictive factors for esophageal stenosis in patients receiving prophylactic steroid therapy after endoscopic submucosal dissection for esophageal squamous cell carcinoma

BACKGROUND

Methods to prevent esophageal stenosis (ES) after endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC) have received increasing attention. Although steroid administration is a prophylactic treatment, the risk factors for ES during prophylactic steroid therapy remain unknown. Therefore, this study aimed to retrospectively evaluate the risk factors for refractory ES in patients administered prophylactic steroids after ESD for ESCC.

METHODS

Among 795 patients with ESCC (854 lesions), 180 patients (211 lesions) administered local triamcinolone acetonide (TrA) and/or oral prednisolone were recruited for this study. We compared the total number of endoscopic balloon dilatation (EBD) procedures performed for post-ESD ES and clinical findings (tumor size, ESD history or chemoradiation therapy [CRT], entire circumferential resection, muscle layer damage, supplemental oral prednisolone administration, EBD with TrA injection, and additional CRT) between patients with refractory and non-refractory ES. EBD was continued until dysphagia resolved. We categorized cases requiring ≥ 8 EBD procedures as refractory postoperative stenosis and divided the lesions into two groups.

RESULTS

Multivariate logistic regression analysis revealed that factors such as ESD history, CRT history, tumor size, and entire circumferential resection were independently associated with the development of refractory ES. The withdrawal rates of EBD at 3 years were 96.1% (52/53) and 58.5% (39/59) in the non-refractory and refractory groups, respectively.

CONCLUSIONS

Our data suggest that entire circumferential resection and CRT history are risk factors for refractory post-ESD ES in ESCC, even with prophylactic steroid administration.

Long-term outcomes of patients with obscure gastrointestinal bleeding after negative capsule endoscopy

BACKGROUND AND AIM

Although small-bowel capsule endoscopy (CE) is widely used for obscure gastrointestinal bleeding (OGIB), long-term outcomes for OGIB patients after negative CE remain unclear. Herein, we defined negative CE as P0 (no bleeding potential) or P1 (less likely to bleed), based on the P classification using CE. We aimed to clarify long-term outcomes of patients with OGIB after negative CE.

METHODS

This single-center observational study enrolled 461 consecutive patients with OGIB who underwent CE from March 2014 to October 2021 and were followed up for >1 year. We examined rebleeding rates and predictive factors.

RESULTS

Two hundred and twenty-four (49%) patients had P0, and 237 (51%) had P1 findings. Rebleeding occurred in 9% and 16% of patients in the P0 and P1 groups, respectively. Two patients in the P0 group and 15 in the P1 group showed rebleeding from the small bowel. The rate of small-bowel rebleeding was significantly lower in the P0 group than that in the P1 group (1% vs 6%, P = 0.002), as was the cumulative rebleeding rate (P = 0.004). In the multivariate analysis, history of endoscopic hemostasis (hazard ratio [HR] = 15.958, 95% confidence interval [CI]:4.950-51.447, P < 0.001) and P1 CE findings (HR = 9.989, 95% CI: 2.077-48.030, P = 0.004) were independently predicted small-bowel rebleeding.

CONCLUSIONS

OGIB with P0 CE findings rarely showed rebleeding from the small bowel. Rebleeding may occur in patients with OGIB. Patients with history of endoscopic hemostasis for small-bowel lesions or P1 CE findings should be followed up intensively.

Hybrid endoscopic submucosal dissection as a salvage option for difficult colorectal conventional endoscopic submucosal dissection

BACKGROUND

When total submucosal dissection is difficult to achieve during conventional colorectal endoscopic submucosal dissection (C-ESD), the lesion can be resected by final snaring through salvage hybrid ESD (SH-ESD). This study aimed to examine the outcomes of SH-ESD and identify its indications that could achieve en bloc resection.

METHODS

We recruited 1039 consecutive patients with colorectal lesions that underwent ESD at Hiroshima University Hospital between January 2015 and December 2020. C-ESD was attempted thoroughly in 924 lesions (C-ESD group, including 9 lesions in which ESD was discontinued), and SH-ESD was performed owing to some difficulties in 115 lesions (SH-ESD group). Risk factors for incomplete resection by SH-ESD and ESD discontinuation were evaluated using multivariate analysis. The outcomes were compared between cases with remaining undissected submucosa of < 20 mm in diameter in the SH-ESD and C-ESD groups, using propensity score matching.

RESULTS

Multivariate analysis revealed that a procedure time > 80 min and remaining undissected submucosa ≥ 20 mm in diameter were significant risk factors for incomplete resection after SH-ESD and ESD discontinuation. By propensity score matching analysis, procedure time was significantly shorter in the SH-ESD group with remaining undissected submucosa < 20 mm in diameter than in the C-ESD group (71 min vs. 90 min, p = 0.0053), although no significant difference was found in the en bloc resection rate (94% vs. 87%, p = 0.0914).

CONCLUSION

SH-ESD can be an alternative surgical method when conventional ESD is difficult to continue in cases in which the remaining undissected submucosa is < 20 mm in diameter.

Disease surveillance evaluation of primary small-bowel follicular lymphoma using capsule endoscopy images based on a deep convolutional neural network (with video)

BACKGROUND AND AIMS

Capsule endoscopy (CE) is useful in evaluating disease surveillance for primary small-bowel follicular lymphoma (FL), but some cases are difficult to evaluate objectively. This study evaluated the usefulness of a deep convolutional neural network (CNN) system using CE images for disease surveillance of primary small-bowel FL.

METHODS

We enrolled 26 consecutive patients with primary small-bowel FL diagnosed between January 2011 and January 2021 who underwent CE before and after a watch-and-wait strategy or chemotherapy. Disease surveillance by the CNN system was evaluated by the percentage of FL-detected images among all CE images of the small-bowel mucosa.

RESULTS

Eighteen cases (69%) were managed with a watch-and-wait approach, and 8 cases (31%) were treated with chemotherapy. Among the 18 cases managed with the watch-and-wait approach, the outcome of lesion evaluation by the CNN system was almost the same in 13 cases (72%), aggravation in 4 (22%), and improvement in 1 (6%). Among the 8 cases treated with chemotherapy, the outcome of lesion evaluation by the CNN system was improvement in 5 cases (63%), almost the same in 2 (25%), and aggravation in 1 (12%). The physician and CNN system reported similar results regarding disease surveillance evaluation in 23 of 26 cases (88%), whereas a discrepancy between the 2 was found in the remaining 3 cases (12%), attributed to poor small-bowel cleansing level.

CONCLUSIONS

Disease surveillance evaluation of primary small-bowel FL using CE images by the developed CNN system was useful under the condition of excellent small-bowel cleansing level.

No significant association between non-Helicobacter pylori Helicobacter infection with gastritis-related indices and gastric cancer

BACKGROUND

Non-Helicobacter pylori Helicobacter (NHPH) has recently been linked to various gastric diseases. However, the relationship between NHPH infection and gastric cancer remains controversial. This study aimed to identify the effect of NHPH infection on gastritis and gastric cancer development.

MATERIALS AND METHODS

Formalin-fixed paraffin-embedded tissues were obtained from 73 patients with gastric cancer, of whom 21 cases were Helicobacter pylori (Hp) current infection, 37 cases were Hp previous infection, and 15 cases were Hp naïve infection, and were screened for NPHPs using polymerase chain reaction. The results were compared with NHPH infection rates in the patients with gastritis-related diseases reported in the previous study. We evaluated the association of NHPH infection with gastritis and clinicopathological features of gastric cancer.

RESULTS

NHPH infection rates were 4/21 (19%) in "Hp current" patients, 4/37 (11%) in "Hp previous" infection patients, and 1/15 (7%) in "Hp naïve" patients, showing no significant difference in infection rates based on Hp infection status. NHPH infection rates in gastric cancer patients were similar to those in the patients with gastritis-related diseases reported in the previous study. A comparison of NHPH-positive and negative patients showed no significant differences in atrophic gastritis status, serum gastritis markers, or clinicopathological characteristics of gastric cancer, such as localization, size, gross type, differentiation, or depth.

CONCLUSIONS

The association between gastric cancer and NHPH infection would have important implications for gastric cancer prevention, diagnostics, and treatment, however, no significant association was found in this particular population.

Investigating the Role of Tumor-Infiltrating Lymphocytes as Predictors of Lymph Node Metastasis in Deep Submucosal Invasive Colorectal Cancer: A Retrospective Cross-Sectional Study

The role of tumor-infiltrating T cells (TILs) in colorectal cancer (CRC) and their significance in early-stage CRC remain unknown. We investigated the role of TILs in early-stage CRC, particularly in deep submucosal invasive (T1b) CRC. Sixty patients with CRC (20 each with intramucosal [IM group], submucosal invasive [SM group], and advanced cancer [AD group]) were randomly selected. We examined changes in TILs with tumor invasion and the relationship between TILs and LN metastasis risk. Eighty-four patients with T1b CRC who underwent initial surgical resection with LN dissection or additional surgical resection with LN dissection after endoscopic resection were then selected. TIL phenotype and number were evaluated using triple immunofluorescence for CD4, CD8, and Foxp3. All subtypes were more numerous according to the degree of CRC invasion and more abundant at the invasive front of the tumor (IF) than in the center of the tumor (CT) in the SM and AD groups. The increased Foxp3 cells at the IF and high ratios of Foxp3/CD4 and Foxp3/CD8 positively correlated with LN metastasis. In conclusion, tumor invasion positively correlated with the number of TILs in CRC. The number and ratio of Foxp3 cells at the IF may predict LN metastasis in T1b CRC.

Indications for Dental Floss Clip Traction During Gastric Endoscopic Submucosal Dissection by Less-Experienced Endoscopists

PURPOSE

Dental floss clip (DFC) traction-assisted endoscopic submucosal dissection (ESD) is widely performed owing to its simplicity. This study aimed to clarify the appropriate indications for the DFC traction method in early gastric cancer when ESD is performed by less-experienced endoscopists.

METHODS AND METHODS

We retrospectively analyzed 1,014 consecutive patients who had undergone gastric ESD performed by less-experienced endoscopists between January 2015 and December 2020. Gastric ESD was performed without DFC in all cases before December 2017 [DFC (-) group, 376 cases], and ESD was performed with DFC in all cases after January 2018 [DFC (+) group, 436 cases]. The procedure time and rates of en bloc resection, complete resection, and adverse events of the groups were compared.

RESULTS

The procedure time did not differ significantly between the 2 groups. However, when comparing lesions >20 mm, the procedure time in the DFC (+) group was significantly shorter than that in the DFC (-) group (95±46 vs. 75±31, P<0.01). The procedure time for lesions located in the greater curvature of the upper or middle stomach and lesions >20 mm located in the lesser curvature side of the stomach in the DFC (+) group was significantly shorter than that in the DFC (-) group.

CONCLUSIONS

The indications for DFC during gastric ESD by less-experienced endoscopists include lesions located in the greater curvature of the upper or middle stomach, and lesions >20 mm located in the lesser curvature of the stomach.

Usefulness and Educational Benefit of a Virtual Scale Endoscope in Measuring Colorectal Polyp Size

INTRODUCTION

The virtual scale endoscope (VSE) is a newly introduced endoscope that helps endoscopists in measuring colorectal polyp size (CPS) during colonoscopy by displaying a virtual scale. This study aimed to determine the usefulness of the VSE for CPS measurement and the educational benefit of using VSE images to improve CPS estimation accuracy.

METHODS

This study included 42 colorectal polyps in 26 patients treated at Hiroshima University Hospital. In study 1, CPS measured using a VSE before endoscopic mucosal resection was compared with CPS measured on resected specimens, and the agreement between the two measurement methods was evaluated via Bland-Altman analysis. In study 2, 14 endoscopists (5 beginners, 5 intermediates, and 4 experts) took a pre-test to determine the size of 42 polyps. After the pre-test, a lecture on CPS measurement using VSE images was given. One month later, the endoscopists took a post-test to compare CPS accuracy before and after the lecture.

RESULTS

In study 1, Bland-Altman analysis revealed no fixed or proportional errors. The mean bias ±95% limits of agreement (±1.96 standard deviations) of the measurement error was -0.05 ± 0.21 mm, indicating that the agreement between two measurement methods was sufficient. In study 2, the accuracy of CPS measurement was significantly higher among beginners (59.5% vs. 26.7%, p < 0.01) and intermediates (65.2% vs. 44.3%, p < 0.05) in the post-test than in the pre-test.

CONCLUSION

The VSE accurately measures CPS before resection, and its images are useful teaching tools for beginner and intermediate endoscopists.

Diagnostic performance of the normal range of gastrin calculated using strict criteria based on a combination of serum markers and pathological evaluation for detecting gastritis: a retrospective study

BACKGROUND

The ABC method, which combines the pepsinogen method and anti-Helicobacter pylori antibody titers, has been used for risk screening for gastric cancer in Japan. However, it has been reported that there are cases of gastritis and carcinogenesis risk even in group A, which is considered to be a low-risk group based on the ABC method. Currently, in group A, endoscopic examination is needed to strictly discriminate "patients without gastritis" (defined as true A patients) from those "with gastritis." A simple and minimally invasive diagnostic criterion for gastritis using serological markers is desirable. In this study, we aimed to identify the normal serum gastrin concentrations in normal stomach cases based on pathological diagnosis and investigate the usefulness of serum gastrin concentrations in diagnosing gastritis.

METHODS

Patients who underwent endoscopy and blood tests at Hiroshima University Hospital were enrolled in the study and categorized into the "pathologically-evaluated group" and "endoscopically-evaluated group," according to the evaluation method of atrophic gastritis. Initially, we measured serum gastrin concentrations in the normal stomach cases in the pathologically-evaluated group and calculated the normal range of serum gastrin concentrations. We used the upper limit of this normal range of serum gastrin concentrations and performed a validation study to determine its usefulness as a diagnostic marker for distinguishing between cases of gastritis and true A in the endoscopically-evaluated group.

RESULTS

The 95th percentile of serum gastrin concentrations in pathologically-evaluated normal stomach cases was 34.12-126.03 pg/mL. Using the upper limit of this normal range of serum gastrin concentrations, the sensitivity, specificity, positive predictive value, and negative predictive value for gastritis were 52.8%, 92.6%, 97.0%, and 31.0%, respectively. Additionally, the receiver operating characteristic (ROC) curve for the endoscopically-evaluated group showed an area under the ROC curve of 0.80.

CONCLUSION

The gastrin cut-off value of 126 pg/mL has a good positive predictive value (97.0%) for detecting gastritis positing its use as a marker for cases requiring endoscopy. However, the identification of patients with gastritis having normal serum gastrin concentrations due to insufficient sensitivity remains a challenge for the future.

Synchronous gastric MALT lymphoma and gastric adenocarcinoma of fundic gland type arising from a hamartomatous inverted polyp in a Helicobacter pylori naive patient

We present a rare case that showed the coexistence of gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma in Helicobacter pylori-naive stomach. A 72-year-old man was followed up after surgery for epithelial carcinoma of the glottis at the Department of Otolaryngology. He underwent an upper gastrointestinal endoscopy for an abnormal PET-CT accumulation, which revealed gastric adenocarcinoma of fundic gland type in the gastric fundus and MALT lymphoma in the upper gastric body. Hence, we performed an endoscopic submucosal dissection for gastric cancer and diagnosed gastric adenocarcinoma of fundic gland type derived from a hamartomatous-inverted polyp. Subsequently, Gastric MALT lymphoma was treated with radiation therapy because the API2-MALT1 gene was positive and the Helicobacter pylori infection was negative. A complete response was observed. Even in Hp-naive stomachs, cases such as the present case are complicated by special types of gastric cancer and MALT lymphoma, and endoscopic examination should be performed with these diseases in mind.

A case of ischemic stroke associated with protein-losing gastroenteropathy and protein S deficiency

Protein-losing gastroenteropathies are characterized by an excessive loss of serum proteins into the gastrointestinal tract, resulting in hypoalbuminemia. Some rare cases are complicated with ischemic stroke. We report a 24-year-old woman who developed acute dysarthria and right hemiplegia 4 months after delivering her first baby by cesarean section. Diffusion-weighted magnetic resonance imaging showed a high-intensity signal in the left anterior cerebral artery territory and middle cerebral artery territory. She had marked hypoalbuminemia and decreased protein S activity. We identified protein-losing gastroenteropathy as the cause of the hypoalbuminemia, and she had a missense mutation of the PROS 1 gene, which was associated with decreased protein S activity. We speculated that the development of protein-losing gastroenteropathy accelerated the decline in protein S activity and caused cerebral infarction.

Endoscopic findings suggestive of a high risk of non-radical cure after definitive chemoradiotherapy for cT1bN0M0 esophageal squamous cell carcinoma

BACKGROUND

Definitive chemoradiotherapy (DCRT) is a curative treatment option for cT1bN0M0 esophageal squamous cell carcinoma (ESCC); however, local residual disease and recurrence after complete remission may occur. We aimed to identify endoscopic findings associated with the risk of non-radical cure (local remnant or recurrence) after DCRT for cT1bN0M0 ESCC.

METHODS

We retrospectively analyzed 40 consecutive patients with cT1bN0M0 ESCC who had undergone DCRT between January 2007 and December 2017. We examined the endoscopic findings in patients with residual or recurrent (RR) disease (RR group) and those without RR disease [non-RR (NRR) group] after DCRT. We also evaluated outcomes after DCRT for each endoscopic finding.

RESULTS

There were 10 patients in the RR group and 30 patients in the NRR group. The RR group had a significantly larger tumor size and a higher proportion of lesions with type 0-I. The 5-year relapse-free survival rate was significantly lower in type 0-I and in the presence of B3 vessels. Endoscopic findings in 15 patients with cT1bN0M0 ESCC, type 0-I, who underwent DCRT revealed significantly more reddish lesions in the RR group compared to the NRR group.

CONCLUSIONS

cT1bN0M0 ESCC large size, with B3 vessels, and type 0-I has a high risk of non-radical cure after DCRT, especially the reddish type 0-I, which may need to be considered for treatment similar to advanced cancer, including surgery with preoperative DCRT.

Efficacy of the specialized scissor-type knife for gastric endoscopic submucosal dissection: a propensity score matched retrospective study

Background and study aims  Prevention of bleeding and perforation during gastric endoscopic submucosal dissection (ESD) is important. Scissor-type knives can accurately grasp and incise the targeted tissue using electrosurgical currents, thereby eliminating unexpected incisions. The SB Knife GX, a scissor-type knife specialized for gastric ESD, was released in June 2016 in Japan. The aim of the present study was to evaluate the efficacy and safety of gastric ESD using the SB Knife GX. Patients and methods  A total of 716 patients who underwent gastric ESD at Hiroshima University Hospital between July 2016 and December 2020 were retrospectively reviewed. From these, 671 patients underwent ESD using the IT Knife 2 (IT-2 group), while 45 underwent ESD using an SB Knife GX (SB-GX group). After propensity score matching, the procedure time, specimen size, en bloc and complete resection rates, and intraoperative bleeding, delayed bleeding, and perforation rates were evaluated. Results  No significant differences were observed in mean procedure time (SB-GX group: 115 ± 165 min; IT-2 group: 95 ± 61 min; P  = 0.82) and en bloc and complete resection rates between the two groups. Intraoperative bleeding rates were significantly lower in the SB-GX group than in the IT-2 group (18 % vs. 40 %; P  = 0.01), and there were no differences in delayed bleeding (4 % vs. 4 %) or perforation (0 % vs. 4 %) between the two groups. Conclusions  The SB Knife GX was proven to be useful for control of intraoperative bleeding during gastric ESD, although the procedure time tended to be longer.

The Anti-Tumor Effect of the Newly Developed LAT1 Inhibitor JPH203 in Colorectal Carcinoma, According to a Comprehensive Analysis

A novel large neutral amino acid transporter 1 (LAT1)-specific inhibitor, JPH203, is expected to cause cancer-specific starvation and possess anti-tumor effects; however, its anti-tumor mechanism for colorectal cancer (CRC) remains unclear. We analyzed LAT family gene expressions in public databases using UCSC Xena and evaluated LAT1 protein expression using immunohistochemistry in 154 cases of surgically resected CRC. We also evaluated mRNA expression using polymerase chain reaction in 10 CRC cell lines. Furthermore, JPH203 treatment experiments were conducted in vitro and in vivo using an allogeneic immune-responsive mouse model with abundant stroma created via the orthotopic transplantation of the mouse-derived CRC cell line CT26 and mesenchymal stem cells. The treatment experiments were followed by comprehensive gene expression analyses with RNA sequencing. Database analyses and immunohistochemistry research on clinical specimens revealed that LAT1 expression was cancer-dominant, and its increase was accompanied by tumor progression. In vitro, JPH203 was effective in an LAT1 expression-dependent manner. In vivo, JPH203 treatment considerably reduced tumor size and metastasis, and RNA sequencing-based pathway analysis showed that not only tumor growth and amino acid metabolism pathways, but also stromal activation-related pathways were suppressed. The results of the RNA sequencing were validated in the clinical specimens, as well as both in vitro and in vivo. LAT1 expression in CRC plays an important role in tumor progression. JPH203 may inhibit the progression of CRC and tumor stromal activity.

Anti-tumor necrosis factor-alpha monoclonal antibody suppresses colorectal cancer growth in an orthotopic transplant mouse model

The risk of malignant tumor progression has been a concern associated with the use of anti-tumor necrosis factor-alpha monoclonal antibody (anti-TNFα mAb). On the contrary, recent observational studies have reported negatively on this risk and instead suggested that anti-TNFα mAb acts as a tumor suppressor in inflammatory carcinogenesis models and subcutaneous transplant models of colorectal cancer. However, no consensus has been established regarding the actual effects of anti-TNFα mAb on malignant tumors. Here, we aimed to evaluate, for the first time, the effect of anti-TNFα mAb on the tumor microenvironment in the absence of intestinal inflammation in a colorectal cancer orthotopic transplant mouse model suitable for tumor microenvironment assessment. The orthotopic transplantation model was developed by transplanting CT26 cells into the cecum of BALB/c mice. Changes in tumor size and weight were recorded 3 weeks after transplantation, and the tumor microenvironment was assessed via RNA sequencing and immunohistological staining. In the orthotopic transplant model, the administration of anti-TNFα mAb led to a reduction in colorectal cancer. The RNA sequencing analysis showed upregulation of immune-related pathways and apoptosis and suppression of stromal- and tumor growth-related pathways. Additionally, Gene Ontology analysis showed inhibition of angiogenesis. Immunohistochemical staining showed inhibition of tumor growth, increase in apoptosis, suppression of stromal response, suppression of angiogenesis, enhancement of tumor immunity, and reduction in the number of tumor-associated macrophages. Anti-TNFα mAb acts as an inhibitor of tumor progression in the tumor microenvironment of a colorectal cancer orthotopic transplant mouse model.

Outcomes of endoscopic submucosal dissection in patients who develop metachronous superficial esophageal squamous cell carcinoma close to a post-endoscopic submucosal dissection scar

BACKGROUND

The presence of post-endoscopic submucosal dissection (ESD) scars renders complete metachronous superficial esophageal squamous cell carcinoma resection difficult. We aimed to identify the risk factors for incomplete resection of metachronous esophageal squamous cell carcinoma close to the post-ESD scar by ESD.

METHODS

We enrolled patients who developed post-ESD superficial esophageal squamous cell carcinoma at Hiroshima University Hospital between January 2006 and March 2020. We analyzed the outcomes and risk factors of incomplete resection between patients whose lesions were close to (close-to group) and away from (away-from group) the post-ESD scar.

RESULTS

We included 111 patients with 212 lesions. The close-to group had a significantly lower complete resection rate (88.6% [62/70] vs. 98.6% [69/70], p = 0.033), longer procedure time (80.2 ± 47.2 min vs. 60.4 ± 29.3 min, p < 0.01), higher proportion of lesions with severe fibrosis (72.9% [51/70] vs. 5.7% [4/70], p < 0.01), and higher intraoperative bleeding rate (78.6% [55/70] vs. 60.0% [42/70], p = 0.027) than the away-from group. There was no significant difference in the rate of local recurrence, muscle injury, perforation, and stenosis as well as the pathological tumor depth between the groups. Of the 92 lesions in the close-to group, the proportion of lesions located on the oral side of the post-ESD scar significantly affected the incidence of incomplete resection (91.7% [11/12] vs. 53.8% [43/80], p = 0.013).

CONCLUSIONS

Complete resection was more difficult for lesions located on the oral side of the post-ESD scar.

Anti-Programmed Cell Death-1 Antibody and Dasatinib Combination Therapy Exhibits Efficacy in Metastatic Colorectal Cancer Mouse Models

In this study, we investigated the in vivo metastasis suppression effects of the platelet-derived growth factor receptor inhibitor dasatinib, which targets cancer-associated fibroblasts (CAFs), in combination with an anti-programmed cell death-1 (PD-1) antibody. We classified clinical CRC cases as inflamed, excluded, or desert using immunohistochemical analysis and evaluated the tumor stroma. The excluded type was the most common, and cases with high-volume stroma in the primary lesions also had a high stromal volume in the liver metastatic lesions. Liver-metastasis mouse models with different stromal volumes were established and treatment-induced changes in the tumor immune microenvironment were evaluated. The anti-PD-1 antibody alone exhibited a therapeutic effect for the liver metastases with low stromal volumes but not for the liver metastases with high stromal volumes. In contrast, antitumor effects were observed with anti-PD-1 antibody/dasatinib combination therapy even in the liver metastases with high stromal volumes. Combination therapy reduced the stromal volume, promoted immune cell infiltration, induced antitumor cytotoxic T-cell responses, activated antitumor immunity, and promoted tumor regression. These results suggest that CAFs play an important role in the immune evasion of CRC and that anti-PD-1 antibody/dasatinib combination therapy has potential as a treatment option for patients with metastatic CRC for whom immunotherapy alone is ineffective.

Predictive factors for the progression of primary localized stage small-bowel follicular lymphoma

BACKGROUND

Primary small-bowel follicular lymphoma (FL) is mainly diagnosed as a duodenal lesion during esophagogastroduodenoscopy. Recently, with the widespread use of small-bowel endoscopy, FL in the jejunum and ileum has been detected. Most patients with small-bowel FL are diagnosed at the localized stage, and a watch-and-wait policy is used. However, the predictive factors for the progression of small-bowel FL have not been clarified. This study retrospectively examined the predictive factors for the progression of primary localized stage small-bowel FL based on clinicopathological and endoscopic findings.

METHODS

We enrolled 60 consecutive patients with primary small-bowel FL diagnosed at two tertiary hospitals between January 2005 and December 2020, with localized stage, low grade, and low tumor burden with the watch-and-wait policy. We examined the predictive factors for progression according to the clinicopathological and endoscopic findings. Endoscopic findings were focused on the color tone, circumferential location of follicular lesions (circumference ≥ 1/2 or < 1/2), fusion of follicular lesions (fusion [ +] or [ -]), and protruded lesions (≥ 6 mm or < 6 mm).

RESULTS

Progressive disease was observed in 12 (20%) patients (mean observation period, 76.4 ± 55.4 months). In the multivariate analysis, "circumference ≥ 1/2" and "fusion (+)" were significant predictive factors for progression. According to the Kaplan-Meier analysis, progression-free survival was significantly shorter in the "circumference ≥ 1/2" and/or "fusion (+)" group than in the "circumference < 1/2" and "fusion ( -)" group.

CONCLUSIONS

Endoscopic findings of "circumference ≥ 1/2" and "fusion (+)" were significant predictive factors for the progression of primary localized stage small-bowel FL.

Diagnostic yield of proximal jejunal lesions with third-generation capsule endoscopy

Objectives

Capsule endoscopy (CE) has been shown to have poor diagnostic performance when the capsule passes quickly through the small bowel, especially the proximal jejunum. This study aimed to evaluate the diagnostic yield of proximal jejunal lesions with third-generation CE technology.

Methods

We retrospectively examined 138 consecutive patients, 76 (55.0%) of whom were men. The patients' median age was 70 years, and proximal jejunal lesions were detected by CE and/or double-balloon endoscopy at Hiroshima University Hospital between January 2011 and June 2021. We analyzed the diagnostic accuracy of CE for proximal jejunal lesions and compared the characteristics of the discrepancy between the use of CE and double-balloon endoscopy with Pillcam SB 2 (SB2) and Pillcam SB 3 (SB3).

Results

SB2 and SB3 were used in 48 (35%) and 90 (65%) patients, respectively. There was no difference in baseline characteristics between these groups. Small-bowel lesions in the proximal jejunum comprised 75 tumors (54%), 50 vascular lesions (36%), and 13 inflammatory lesions (9%). The diagnostic rate was significantly higher in the SB3 group than in the SB2 group for tumors (91% vs. 72%, p < 0.05) and vascular lesions (97% vs. 69%, p < 0.01). For vascular lesions, in particular, the diagnostic rate of angioectasia improved in the SB3 group (100%) compared with that in the SB2 group (69%).

Conclusions

SB3 use improved the detection of proximal jejunal tumors and vascular lesions compared with SB2 use.

Investigation of endoscopic findings in nine cases of Helicobacter suis-infected gastritis complicated by gastric mucosa-associated lymphoid tissue lymphoma

BACKGROUND

We have previously reported that eradication therapy was more effective against Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma in non-Helicobacter pylori Helicobacter (NHPH)-positive cases than in NHPH-negative cases and that the infection status of NHPH could be a predictive marker for the efficacy of eradication therapy for H. pylori negative gastric MALT lymphoma. However, a diagnostic test for NHPH infection has not yet been clinically established. In this study, we investigated the endoscopic findings in cases of H. suis-infected gastritis associated with gastric MALT lymphoma reported at our institution.

MATERIALS AND METHODS

Participants were selected from cases of gastric MALT lymphoma who underwent esophagogastroduodenoscopy at Hiroshima University Hospital, who were negative for the API2-MALT1 gene, and who received eradication therapy as a first-line treatment. We examined the endoscopic findings in nine cases from this group in which H. suis infection was confirmed by polymerase chain reaction.

RESULTS

Endoscopic findings, such as cracked mucosa, spotty redness, nodular gastritis-like appearance, and white marbled appearance, which have been reported as characteristics of NHPH gastritis, were observed in multiple cases. The most common endoscopic findings in this study were cracked mucosa (7/9 cases), followed by spotty redness (6/9 cases), nodular gastritis-like appearance (5/9 cases), and white marbled appearance (2/9 cases).

CONCLUSIONS

Our study may serve as a reference for re-evaluation of the diagnostic criteria for H. suis infection and indications for eradication therapy, particularly for cases of H. pylori negative gastric MALT lymphoma, where endoscopic findings such as those seen in this study were observed in the background mucosa.

Clinical outcomes of endoscopic resection for rectal neuroendocrine tumors: Advantages of endoscopic submucosal resection with a ligation device compared to conventional EMR and ESD

Objectives

Methods

Results

Conclusions

Characteristics and Treatment Outcomes of Small-bowel Angioectasia in Systemic Sclerosis Patients: A Retrospective Observational Study

Objective Systemic sclerosis (SSc) is defined as an autoimmune disease presenting with fibrosis of various organs and vascular endothelial damage. Vascular lesions, including small-bowel angioectasias, are also frequently detected in SSc patients. Polidocanol injection (PDI) is a safe and effective hemostatic treatment for gastrointestinal bleeding. We evaluated the outcomes of PDI for small-bowel angioectasia in SSc patients. Methods We retrospectively evaluated 65 consecutive SSc patients (61 women; mean age, 64.3 years old) who underwent capsule endoscopy (CE) and/or double-balloon endoscopy at Hiroshima University Hospital between April 2012 and December 2019. Patients Patients were stratified according to the presence of small-bowel angioectasia. Among patients who underwent CE during the same period, those with small-bowel angioectasia without concomitant diseases were compared with SSc patients with small-bowel angioectasia. Clinical and endoscopic characteristics, treatment outcomes, and the incidence of metachronous small-bowel angioectasia after PDI were evaluated. Results SSc patients with small-bowel angioectasia exhibited significantly lower hemoglobin levels and a significantly higher incidence of skin telangiectasia than those without small-bowel angioectasia. On a multivariate analysis of the presence of small-bowel angioectasia, anemia and skin telangiectasia were significant independent factors. SSc patients with small-bowel angioectasia included a higher proportion of women and exhibited a significantly higher incidence of metachronous small-bowel angioectasia than X. The characteristics of small-bowel angioectasia and outcomes of PDI were not significantly different between the two groups. No post-treatment rebleeding cases or adverse events were noted. Conclusion CE should be performed for SSc patients with anemia and/or skin telangiectasia. PDI is effective for SSc patients with small-bowel angioectasia.

Vertical tumor margin of endoscopic resection for T1 colorectal carcinoma affects the prognosis of patients undergoing additional surgery

BACKGROUND

Vertical tumor margin-negative T1 colorectal carcinoma (CRC) is an absolute curative condition following complete endoscopic resection (ER). However, the influence on prognosis in relation to vertical tumor margin is unclear. Therefore, we evaluated the influence of the distance from vertical tumor margin to resected specimen edge (vertical margin distance) of ER for T1b (submucosal invasion depth > 1000 μm) CRC on the prognosis of patients undergoing additional surgery after ER.

METHODS

In total, 215 consecutive patients with T1b CRC who underwent additional surgery after ER at Hiroshima University Hospital between February 1992 and June 2019 were enrolled. We assessed 191 patients without lymph node metastases at the additional surgery. The specimens resected by ER were classified into three groups based on the vertical margin distance: patients with a vertical margin distance of ≥ 500 μm (Group A); patients with a vertical margin distance of < 500 μm (Group B); and patients with a positive vertical tumor margin (Group C). Subsequently, we evaluated the prognosis of the patients in relation to the clinicopathological characteristics among the three groups.

RESULTS

There were no significant differences in clinicopathological characteristics among the three groups. Group A had a significantly higher recurrence-free 5-year survival rate than Groups B and C (100%, 84.5%, and 81.8%, respectively). Similarly, Group A had a significantly higher disease-specific 5-year survival rate than Group C (100% vs. 95.5%).

CONCLUSIONS

Complete en bloc resection with sufficient submucosal layer from the invasive front (vertical margin distance > 500 μm) by ER for T1 CRC reduces the risk of metastatic recurrence after additional surgery.

Involvement of non-Helicobacter pylori helicobacter infections in Helicobacter pylori-negative gastric MALT lymphoma pathogenesis and efficacy of eradication therapy

BACKGROUND

Eradication therapy is known to be effective against Helicobacter pylori-positive gastric MALT lymphoma but predicting the efficacy of eradication therapy against Helicobacter pylori-negative gastric MALT lymphoma is difficult. Recent reports have shown that non-Helicobacter pylori helicobacter infections induce gastric MALT lymphoma, and we aimed to clarify whether non-Helicobacter pylori helicobacter infections are associated with the efficacy of eradication therapy.

METHODS

We analyzed eradication therapy as a first-line treatment for 182 cases of gastric MALT lymphoma, classified according to Helicobacter pylori infection and API2-MALT1 mutation status. We also evaluated the non-Helicobacter pylori helicobacter infection status in 29 Helicobacter pylori-negative cases via PCR with DNA extracted from paraffin-embedded biopsy tissues. Finally, we analyzed the relationship between non-Helicobacter pylori helicobacter infection status and eradication therapy outcome.

RESULTS

The API2-MALT1 mutation was observed in 13/182 patients (7.1%), none of whom were cured by eradication therapy. Helicobacter pylori-negative cases had a significantly higher non-Helicobacter pylori helicobacter infection rate than Helicobacter pylori-positive cases (16/29, 55% vs. 3/29, 10%; P < 0.05). Among the Helicobacter pylori-negative cases, non-Helicobacter pylori helicobacter-positive cases had a significantly higher complete response rate than non-Helicobacter pylori helicobacter-negative cases (12/16, 75% vs. 3/13, 23%; P < 0.05).

CONCLUSION

Helicobacter pylori-negative and API2-MALT1-negative gastric MALT lymphoma cases exhibited a high rate of non-Helicobacter pylori helicobacter infections, which may have contributed to the success of eradication therapy. Therefore, we recommend eradication therapy as a first-line treatment for non-Helicobacter pylori helicobacter-positive gastric MALT lymphoma.

Role of tumor-associated macrophages at the invasive front in human colorectal cancer progression

Macrophages are an essential component of antitumor activity; however, the role of tumor‐associated macrophages (TAMs) in colorectal cancer (CRC) remains controversial. Here, we elucidated the role of TAMs in CRC progression, especially at the early stage. We assessed the TAM number, phenotype, and distribution in 53 patients with colorectal neoplasia, including intramucosal neoplasia, submucosal invasive colorectal cancer (SM‐CRC), and advanced cancer, using double immunofluorescence for CD68 and CD163. Next, we focused on the invasive front in SM‐CRC and association between TAMs and clinicopathological features including lymph node metastasis, which were evaluated in 87 SM‐CRC clinical specimens. The number of M2 macrophages increased with tumor progression and dynamic changes were observed with respect to the number and phenotype of TAMs at the invasive front, especially at the stage of submucosal invasion. A high M2 macrophage count at the invasive front was correlated with lymphovascular invasion, low histological differentiation, and lymph node metastasis; a low M1 macrophage count at the invasive front was correlated with lymph node metastasis. Furthermore, receiver operating characteristic curve analysis revealed that the M2/M1 ratio was a better predictor of the risk of lymph node metastasis than the pan‐, M1, or M2 macrophage counts at the invasive front. These results suggested that TAMs at the invasive front might play a role in CRC progression, especially at the early stages. Therefore, evaluating the TAM phenotype, number, and distribution may be a potential predictor of metastasis, including lymph node metastasis, and TAMs may be a potential CRC therapeutic target.

Mesenchymal stem cells induce tumor stroma formation and epithelial‑mesenchymal transition through SPARC expression in colorectal cancer

Tumor-stroma interactions serve a crucial role in the development of colorectal cancer (CRC), in which secreted protein acidic and rich in cysteine (SPARC) has been implicated. Due to interactions between cancer and stromal cells [mesenchymal stem cells (MSCs)], SPARC gene expression is markedly upregulated in CRC cells. The present study investigated the role of SPARC in CRC development and its potential as a biomarker. Specifically, the present study examined the association between SPARC expression and clinicopathological characteristics in 42 cases of CRC. SPARC expression in cancer cells was associated with T grade, N grade (TNM classification), stage and poor prognosis. Furthermore, the area of fibroblast-activating protein-positive staining around the cancer cells was increased in SPARC-positive compared with SPARC-negative cases. Proliferation and wound healing assays in SPARC-silenced KM12SM cells [short hairpin RNA SPARC (shSPARC)], the reduced SPARC expression of which was demonstrated by reverse transcription-quantitative PCR, revealed that the proliferative and migratory capacity of shSPARC cells did not differ from that of wild-type (WT) cells. However, it was markedly reduced when co-cultured with MSCs. Furthermore, in vivo, immunohistological analysis and RNA sequencing were conducted in an orthotopic implanted mouse model. Tumor growth and lymph node metastasis were markedly suppressed in shSPARC-transplanted tumors compared with WT-transplanted tumors, with a more marked suppression observed following shSPARC co-transplantation with MSCs. Immunohistological examination further revealed that the stromal reaction and epithelial-mesenchymal transition (EMT) were markedly suppressed in tumors co-transplanted with shSPARC and MSCs, and these results were consistent with RNA sequencing using RNA extracted from orthotopic tumors. Overall, these results suggested that SPARC expression in CRC cells is dependent on the interaction between cancer cells and stromal cells to induce EMT and promote stromal formation in the tumor microenvironment, suggesting its suitability as a novel target molecule for CRC treatment.

Genomic Landscape of Early-stage Colorectal Neoplasia Developing From the Ulcerative Colitis Mucosa in the Japanese Population

BACKGROUNDS

Colorectal neoplasias (CRN)s developing from the ulcerative colitis (UC) mucosa include both colitic and sporadic neoplasias. Although several genomic analyses of advanced colitis-associated cancer are available, such studies do not distinguish between colitic and sporadic cases, and the early-stage genomic alterations involved in the onset of colitic cancer remain unclear. To address this, we performed a genomic analysis of early-stage CRN developing from the UC mucosa (CRNUC).

METHODS

We extracted DNA from 36 early-stage CRNUCs (T1 cancer, 10; dysplasia, 26) from 32 UC patients and performed targeted sequencing of 43 genes commonly associated with colitis-associated cancer and compared the results with sequencing data from the Japanese invasive colitis-associated cancer.

RESULTS

The most frequently mutated gene in the CRNUC cohort was APC (mutated in 47.2% of the cases), followed by TP53 (44.4%), KRAS (27.8%), and PRKDC (27.8%). None of the TP53 mutations occurred at any of the hotspot codons. Although the TP53 mutations in The Cancer Genome Atlas of Colorectal Cancer were dispersed throughout the gene, those detected here in CRNUC cases were concentrated in the amino terminal part of the DNA-binding domain. Interestingly, the mutations in KRAS and TP53 were mutually exclusive in CRNUC, and CRNUCs with KRAS mutations had histologically serrated lesions in the gland duct. Mayo endoscopic subscore was higher in TP53-mutated CRNUCs and lower in KRAS-mutated CRNUCs.

CONCLUSIONS

Our findings suggest that early-stage CRNUC can be classified into 2 groups: those developing through the carcinogenic pathway via TP53 mutations and those developing through the carcinogenic pathway via KRAS mutations.

Clinical usefulness of combination therapy with polidocanol injection and argon plasma coagulation for gastric antral vascular ectasia

Background and Aim

Gastric antral vascular ectasia (GAVE) causes gastrointestinal bleeding. The initial treatment for GAVE bleeding is endoscopic hemostasis, and currently, the most performed technique to achieve hemostasis is argon plasma coagulation (APC). However, APC is associated with a high recurrence rate. To overcome this limitation, we examined the outcomes of the combination therapy of APC and polidocanol injection (PDI) for treating GAVE.

Methods

We retrospectively analyzed the outcomes of 15 consecutive GAVE patients treated with PDI + APC at Hiroshima University Hospital between November 2011 and September 2019 with respect to clinical characteristics, hemostatic efficacy, complications related to treatment, and recurrence rate.

Results

The mean age of patients (4 men and 11 women) was 74 ± 8.4 years. Patients had comorbidities of liver cirrhosis (seven patients, 47%), chronic renal failure (seven patients, 47%), and autoimmune diseases (seven patients, 47%). Endoscopic hemostasis with PDI + APC was performed in all patients (n = 15). The mean number of PDIs attempted to stop bleeding was 1.5 ± 0.8 (1–4), and the mean number of APCs attempted was 2.1 ± 1.2 (1–5). Complications related to treatment occurred in two patients (14%): ulceration in one patient and hematoma in another patient, both of whom were treated conservatively. Two patients (13%) had recurrences during the follow‐up period (average period, 42 months). Both were cured with additional treatment of PDI only.

Conclusion

The combination therapy of PDI and APC is effective for GAVE with a low recurrence rate.

Gastric mucosa-associated lymphoid tissue lymphoma in conjunction with multiple lymphomatous polyposis in the context of Helicobacter pylori and Helicobacter suis superinfection

A 53-year-old woman visited a doctor and complained of chest discomfort after meals. Esophagogastroduodenoscopy showed multiple granular elevations in the gastric body. After biopsies from the elevations, she was diagnosed with mucosa-associated lymphoid tissue (MALT) lymphoma. Polymerase chain reaction also detected Helicobacter pylori and H. suis. Treatment to eradicate H. pylori and H. suis was successful. Endoscopic examination after the bacterial eradication treatment showed that multiple granular elevations remained in the gastric body; however, no lymphoma cells were found during histopathological examination. Thus, we reported a case of H. pylori-positive gastric MALT lymphoma with a unique morphology associated with H. suis superinfection.

Stromal reaction inhibitor and immune-checkpoint inhibitor combination therapy attenuates excluded-type colorectal cancer in a mouse model

Despite recent advances in cancer immunotherapy, the efficacy of colorectal cancer (CRC) immunotherapy regimens is limited. This study evaluated the combined effect of an anti-PD-1 antibody and a platelet-derived growth factor receptor inhibitor (imatinib) on CRC progression using an orthotopic transplanted mouse model that reproduced the three histological phenotypes of CRC (inflamed-, excluded-, and desert-type). The frequency of each of these phenotypes in 196 human CRC tissue samples was also evaluated. Excluded-type CRC had the highest frequency in human tissue samples. In the mouse model, imatinib suppressed stromal reaction and increased sensitivity to anti-PD-1 treatment in excluded-type CRC. Antitumor effect was observed in mice with excluded-type tumors only after concomitant administration of anti-PD-1 antibody and imatinib. Immunohistological analysis revealed a reduction in stromal volume and an increase in the number of CD8-positive T cells in the tumor nest following combination therapy. RNA sequencing revealed significant activation of immune-related pathways and suppression of stromal-related pathways in transplanted tumors treated with combination therapy compared with tumors treated with anti-PD-1 antibody monotherapy. This combination therapy may prove effective for CRC cases that are unresponsive to anti-PD-1 antibody monotherapy.

Helicobacter suis infection is associated with nodular gastritis-like appearance of gastric mucosa-associated lymphoid tissue lymphoma

Most patients with gastric mucosa‐associated lymphoid tissue (MALT) lymphoma are infected with Helicobacter pylori, and eradication therapy is the first‐line treatment for localized disease with H pylori infection. However, there were several reports showing effectiveness of eradication therapy in even H pylori negative cases. Gastric MALT lymphomas are endoscopically classified into three common types: superficial, ulcerative, and elevated types. For the past 20 years, we have encountered 200 cases of localized gastric MALT lymphoma. Among them, only 4 cases (2%) showed similar macroscopic findings to those of nodular gastritis (gastric MALT lymphoma with nodular gastritis‐like appearance; M‐NGA). Here, we compared clinicopathological characteristics and prevalence of non‐H pylori Helicobacter (NHPH) infection between M‐NGA and other common types of gastric MALT lymphoma. To examine the prevalence of NHPH infection, DNA was extracted from formalin‐fixed paraffin‐embedded biopsy tissues from four cases of M‐NGA, 20 cases of common endoscopic types of gastric MALT lymphoma, and 10 cases of nodular gastritis. We used a highly sensitive polymerase chain reaction assay to detect the presence of five species of NHPH (Helicobacter suis, H felis, H bizzozeronii, H salomonis, and H heilmannii). H suis infection was detected in 4, 2, and 0 of the 4, 20, and 10 cases of M‐NGA, other types of gastric MALT lymphoma, and nodular gastritis, respectively. Other NHPH species were not detected in any cases. Complete response rate by eradication therapy was 4/4 in M‐NGA cases. Therefore, nodular gastritis‐like MALT lymphoma, which shows a very rare phenotype, is closely associated with NHPH infection, and eradication therapy may be the first‐choice treatment.

A Questionnaire Survey on the Sequence of Events Prior to Undergoing Colonoscopy: The Influence of the Behavioral Response after a Fecal Occult Blood Test on the Early Detection of Colorectal Cancer

Objective The fecal occult blood (FOB) test is commonly used for colorectal cancer screening; however, it is uncertain if further diagnostic interventions, such as a colonoscopy, should be performed based on its results. Method To better understand patient behavior following the FOB test, 6,414 patients (3,807 men and 2,607 women) who underwent colonoscopy between August 2015 and March 2016 at any of the 26 medical institutions throughout Hiroshima Prefecture were invited to participate in the study. All patients provided their written consent, after which they completed a questionnaire, and their colonoscopy results were obtained. These datasets were analyzed in a blinded manner, and the unique codes linking the records were revealed at the end of the analysis. Results Of the total study population, 4,749 patients (74.0%) had previously undergone FOB testing. After classification of common behavioral responses that the patients displayed following their FOB test, the group who had undergone the test several times, who had not had positive test results in the past, and whose latest FOB test results were positive had a significantly higher diagnosis rate of both early- and advanced-stage cancer than the other groups. Furthermore, patients in whom several previous FOB test results had been negative whose previous colonoscopy was positive were associated with a higher diagnosis rate of early-stage cancer than other groups. Conclusion These results suggested that colonoscopy should be performed immediately for patients with positive FOB test results due to their association with colorectal cancer and the possible detection of cancer at an early stage.

Early-stage serrated adenocarcinomas are divided into several molecularly distinct subtypes

Serrated adenocarcinoma (SAC) is considered the end stage of the serrated neoplasia pathway. Although SAC prognosis is not widely recognized, the serrated pathway-associated subtype consistently exhibits unfavorable prognosis in genetic studies. Herein, we classified molecularly distinct subtypes of serrated adenocarcinomas and clarified their associated clinicopathological characteristics and genetic changes. We examined 38 early-stage colorectal SACs. Of these, 24 were classified into three molecularly distinct groups by colon cancer subtyping (CCS). The clinicopathological characteristics, Ki 67 labeling index (LI), and SAC epithelial serration were assessed. The DNA from carcinomas and normal tissue/adenoma was extracted by laser microdissection and sequenced by next-generation sequencing, and mutation numbers and patterns of a 15-oncogene panel were determined. The CCS groups included CCS1 (CDX2+, HTR2B-, FRMD6-, ZEB1-, and microsatellite instable-low [MSI-L]/microsatellite stable [MSS]; 14 cases), CCS2 (microsatellite instable-high [MSI-H], 5 cases), and CCS3 (CDX2-, HTR2B+, FRMD6+, ZEB1+, and MSI-L/MSS; 5 cases). Invasive cancer was significantly more frequent in CCS3 than in CCS1 (5/5 versus 3/14, respectively). Ki67 LI and epithelial serration were higher in CCS3 than in CCS1 (83.0 ± 5.8 versus 65.4 ± 4.0 and 5/5 versus 3/14, respectively; p = 0.031 and 0.0048). CCS2 showed the highest mutation number, whereas KRAS and BRAF mutation numbers were higher in CCS3 than in CCS1. Early-stage SACs were classified into three molecularly distinct subtypes with different clinicopathological and genetic characteristics.

Silencing of Discoidin Domain Receptor-1 (DDR1) Concurrently Inhibits Multiple Steps of Metastasis Cascade in Gastric Cancer

Accumulating evidence suggests that a unique set of receptor tyrosine kinases, known as discoidin domain receptors (DDRs), plays a role in cancer progression by interacting with the surrounding collagen matrix. In this study, we investigated the expression and role of DDR1 in human gastric cancer metastasis. Proliferation, migration, invasion, and tube formation assays were conducted in DDR1-expressing MKN74 gastric cancer cells and corresponding DDR1-silenced cells. The effects of DDR1 on tumor growth and metastasis were examined in orthotopically implanted and experimental liver metastasis models in nude mice. The expression of DDR1 in surgical specimens was analyzed by immunohistochemistry. DDR1 was expressed in human gastric cancer cell lines, and its expression in human gastric tumors was associated with poor prognosis. Among seven gastric cancer cell lines, MKN74 expressed the highest levels of DDR1. DDR1-silenced MKN74 cells showed unaltered proliferation activity. In contrast, migration, invasion, and tube formation were significantly reduced. When examined in an orthotopic nude mouse model, DDR1-silenced implanted tumors significantly reduced angiogenesis and lymphangiogenesis, thereby leading to reductions in lymph node metastasis and liver metastasis. In a model of experimental liver metastasis, DDR1-silenced cells almost completely inhibited liver colonization and metastasis. DDR1 deficiency led to reduced expression of the genes encoding vascular endothelial growth factor (VEGF)-A, VEGF-C, and platelet-derived growth factor-B. These results suggest that DDR1 is involved in gastric cancer tumor progression and that silencing of DDR1 inhibits multiple steps of the gastric cancer metastasis process.

Combination therapy using molecular-targeted drugs modulates tumor microenvironment and impairs tumor growth in renal cell carcinoma

Tumor growth and metastasis are determined not by cancer cells alone but also by a variety of stromal cells, various populations of which overexpress platelet‐derived growth factor receptors (PDGF‐Rs). In addition, activation of PI3K‐AKT‐mammalian target of rapamycin (mTOR) signaling is frequently observed in many cancer types as well. mTOR comprises a serine/threonine kinase that increases the production of proteins that stimulate key cellular processes such as cell growth and proliferation, cell metabolism, and angiogenesis. In this study, we investigated the impact of molecular‐targeting agents including PDGF‐R and mTOR inhibitors on the tumor stroma of human kidney cancer and examined the efficacy of combination therapy with these agents against this disease. Treatment with sunitinib did not suppress tumor growth, but significantly decreased stromal reactivity, microvessel density, and pericyte coverage of tumor microvessels in an orthotopic mouse model. In contrast, treatment with everolimus decreased tumor growth and microvessel density but not stromal reactivity. However, sunitinib and everolimus in combination reduced both the growth rate and stromal reaction. These findings suggest that target molecule‐based inhibition of the cancer–stromal cell interaction appears promising as an effective antitumor therapy.

Abstract 1987: Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces gastric cancer cell motility and metastasis

Accumulating evidences suggest that a unique set of receptor tyrosine kinases, known as discoidin domain receptors (DDRs), play a role in cancer progression by interaction with their surrounding collagen matrix. Although abnormal expression of DDRs is reported in some human cancers, little is known about the expression and function of DDRs in gastric cancer progression. In this study, we investigated expression and the role of DDR1 in the tumor progression of human gastric cancer. The expression and distribution of DDR1 was analyzed by immunohistochemistry in 127 human gastric cancer cases, and the expression level of DDR1 in 7 human gastric cancer cell lines was analyzed by RT-PCR and western blotting. Proliferation, migration, invasion, and tube formation assays were conducted in DDR1 silenced gastric cancer cells. The effect of DDR1 on the tumor growth and metastasis were examined in orthotopically implanted nude mice model and a model of liver metastasis. DDR1 was expressed in human gastric cancer cell lines, and expression of DDR1 in human gastric tumor was associated with poor prognosis. Among 7 gastric cancer cell lines, MKN74 expressed DDR1 at highest level. DDR1-silenced MKN74 cells showed unaltered proliferation activity. In contrast, migration, invasion, and tube formation were significantly reduced. When examined in an orthotopic nude mouse model, DDR1-silenced implanted tumor significantly decreased angiogenesis and lymphangiogensesis, thereby leading to reduction of lymph node metastasis and liver metastasis. We showed that treatment of DDR1 inhibitor also inhibited lymph node metastasis in an orthotopic nude mouse model These results suggest that DDR1 is involved in GC tumor progression and metastasis. DDR1 could be not only an independent prognostic classifier, but also a promising therapeutic target in patients with GC.

Citation Format: Ryo Yuge, Yasuhiko Kitadai, Hidehiko Takigawa, Shinji Tanaka, Kazuaki Chayama, Wataru Yasui. Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces gastric cancer cell motility and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1987. doi:10.1158/1538-7445.AM2017-1987

Abstract 4341: Mesenchymal stem cells promote epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact

We previously reported that in an orthotopic nude mouse model of human colon cancer, bone marrow-derived mesenchymal stem cells (MSCs) migrated to tumor stroma and promoted tumor growth and metastasis. We evaluated the proliferation and migration ability in directly and indirectly co-culture assay to clarify the mechanism of interaction between cancer cells and MSCs. Proliferation and migration ability of cancer cells were increased by direct co-culture with MSCs but not by indirect co-culture of MSCs. Thus, we thought that direct contact between cancer cells and MSCs is important to their interaction. We performed microarray analysis of gene expression in KM12SM colon cancer cells directly co-cultured with MSCs. Expression of epithelial-mesenchymal transition (EMT) related genes such as fibronectin (FN), SPARC and Galectin 1 was increased by direct co-culture with MSCs. We also confirmed the upregulation of these genes with real time PCR, and these genes were not increased in cancer cells indirectly co-cultured with MSCs. Among these EMT related genes upregulated by direct co-culture with MSCs, we examined immune localization of FN, well-known EMT marker. In co-culture assay in chamber slides, expression of FN in cancer cluster was seen only at the edge where cancer cells directly contacted with MSCs. FN expression by cancer cells was increased at the tumor periphery and invasive edge in orthotopic nude mice tumors and human colon cancer tissues, respectively. These results suggest that mesenchymal stem cells induce epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact and may play an important role of colon cancer metastasis.

Citation Format: Hidehiko Takigawa, Yasuhiko Kitadai, Toshio Kuwai, Ryo Yuge, Shinji Tanaka, Kazuaki Chayama. Mesenchymal stem cells promote epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4341. doi:10.1158/1538-7445.AM2017-4341

Mesenchymal Stem Cells Induce Epithelial to Mesenchymal Transition in Colon Cancer Cells through Direct Cell-to-Cell Contact

We previously reported that in an orthotopic nude mouse model of human colon cancer, bone marrow-derived mesenchymal stem cells (MSCs) migrated to the tumor stroma and promoted tumor growth and metastasis. Here, we evaluated the proliferation and migration ability of cancer cells cocultured with MSCs to elucidate the mechanism of interaction between cancer cells and MSCs. Proliferation and migration of cancer cells increased following direct coculture with MSCs but not following indirect coculture. Thus, we hypothesized that direct contact between cancer cells and MSCs was important. We performed a microarray analysis of gene expression in KM12SM colon cancer cells directly cocultured with MSCs. Expression of epithelial-mesenchymal transition (EMT)-related genes such as fibronectin (FN), SPARC, and galectin 1 was increased by direct coculture with MSCs. We also confirmed the upregulation of these genes with real-time polymerase chain reaction. Gene expression was not elevated in cancer cells indirectly cocultured with MSCs. Among the EMT-related genes upregulated by direct coculture with MSCs, we examined the immune localization of FN, a well-known EMT marker. In coculture assay in chamber slides, expression of FN was seen only at the edges of cancer clusters where cancer cells directly contacted MSCs. FN expression in cancer cells increased at the tumor periphery and invasive edge in orthotopic nude mouse tumors and human colon cancer tissues. These results suggest that MSCs induce EMT in colon cancer cells via direct cell-to-cell contact and may play an important role in colon cancer metastasis.

Multikinase inhibitor regorafenib inhibits the growth and metastasis of colon cancer with abundant stroma

Interaction between tumor cells and stromal cells plays an important role in the growth and metastasis of colon cancer. We previously found that carcinoma-associated fibroblasts (CAFs) expressed platelet-derived growth factor receptor-β (PDGFR-β) and that PDGFR targeted therapy using imatinib or nilotinib inhibited stromal reaction. Bone marrow-derived mesenchymal stem cells (MSCs) migrate to tumor stroma and differentiate into CAFs. A novel oral multikinase inhibitor regorafenib inhibits receptor tyrosine kinases expressed on stromal cells (vascular endothelial growth factor receptor 1-3, TIE2, PDGFR-β, and fibroblast growth factors) and tumor cells (c-KIT, RET, and BRAF). These molecules are involved in tumor growth, angiogenesis, lymphangiogenesis, and stromal activation. Therefore, we examined whether regorafenib impaired the tumor-promoting effect of CAFs/MSCs. KM12SM human colon cancer cells alone or KM12SM cells with MSCs were transplanted into the cecal wall of nude mice. Co-implantation of KM12SM cells with MSCs into the cecal wall of nude mice produced tumors with abundant stromal component and promoted tumor growth and lymph node metastasis. Single treatment with regorafenib inhibited tumor growth and metastasis by inhibiting both tumor cells and stromal reaction. This tumor-inhibitory effect of regorafenib was more obvious in tumors developed by co-implanting KM12SM cells with MSCs. Our data suggested that targeting of the tumor microenvironment with regorafenib affected tumor cell-MSC interaction, which in turn inhibited the growth and metastasis of colon cancer.

Regression of Cecal MALT Lymphoma after Antibiotic Treatment in a Patient with Helicobacter pylori Infection

A 63-year-old man with abdominal discomfort was referred to our hospital. Colonoscopy revealed a hemispherical-shaped protruding cecal mass of approximately 10 mm in size with a normal mucosal surface. Biopsy specimens showed nodules consisting of the proliferation of atypical lymphoid cells. Mucosa-associated lymphoid tissue (MALT) lymphoma was diagnosed based on the histological and immunohistochemical findings. Since upper gastrointestinal endoscopy demonstrated Helicobacter pylori-associated atrophic gastritis, eradication therapy was administered. The cecal mass disappeared completely within three months after triple therapy. Therefore, H. pylori eradication therapy may be a useful treatment option for cecal MALT lymphoma.

Abstract 5070: Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces colon cancer cell migration and metastasis

Accumulating evidence suggests that a unique set of receptor tyrosine kinases, known as discoidin domain receptors (DDRs), plays a role in cancer progression by regulating the interactions of tumor cells with their surrounding collagen matrix. We investigated the role of DDR1 in the tumor progression of colorectal cancer.

We examined the DDR1 mRNA and protein expression levels in a series of human colorectal cancer cell lines by RT-PCR and Western blotting. We also analyzed the DDR1 protein expression in 27 surgical specimens of colorectal cancer by immunohistochemistry. Migration, invasion, and proliferation assays were conducted with a high-content time-lapse assay system in a series of colon cancer cell lines. Nilotinib, a well-known DDR1 inhibitor, and DDR1-silenced colon cancer cells were used for inhibition of DDR1 tyrosine kinase activity. In an in vivo study, we orthotopically implanted KM12SM human colon cancer cells into the cecum of nude mice and administered nilotinib (100 mg/kg/day) by daily oral gavage. After 4 weeks of treatment, primary tumors and metastatic lesions were resected, and specimens were analyzed histologically.

DDR1 mRNA and protein expression was observed in the human colon cancer cell lines and in cancer cells of most of the surgical specimens. Colon cancer cell lines KM12SM, KM12c, LoVo, and HT29 exposed to nilotinib (20 μM) showed reduced migration. When incubated with type I collagen, however, these cells showed increased migratory activity. Nilotinib treatment significantly inhibited this effect. The migratory activity of DDR1-silenced cells was not affected by nilotinib treatment. The orthotopic xenografts grew invasively as aggressive tumors with a stromal reaction, but under nilotinib treatment, the stromal reaction was reduced, and tumors grew expansively. In addition, the numbers of lymph node metastases were significantly reduced.

Disruption of DDR1 attenuated colon cancer cell migration and led to altered primary tumor morphology and to impaired lymph node metastasis. DDR1 may be a promising therapeutic target in patients with colon cancer.

Citation Format: Ryo Yuge, Yasuhiko Kitadai, Kei Shinagawa, Mieko Onoyama, Shinji Tanaka, Wataru Yasui, Kazuaki Chayama. Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces colon cancer cell migration and metastasis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5070. doi:10.1158/1538-7445.AM2015-5070

mTOR and PDGF pathway blockade inhibits liver metastasis of colorectal cancer by modulating the tumor microenvironment

Tumor growth and metastasis are not determined by cancer cells alone but also by a variety of stromal cells, and platelet-derived growth factor receptors (PDGF-Rs) are overexpressed by various stromal cell populations. Activation of PI3K-AKT-mTOR signaling is frequently observed in many cancer types. We investigated whether the mTOR inhibitor everolimus, alone or in combination with the PDGF-R tyrosine kinase inhibitor nilotinib, can inhibit growth and metastasis of human colon cancer. The effects of nilotinib and everolimus on tumor growth and metastasis were examined in an orthotopic mouse model of human colon cancer and a model of liver metastasis. After treatment with nilotinib (versus distilled water), the stromal reaction of xenografts growing in the cecal wall and liver was significantly decreased. After treatment with everolimus, the stromal reaction did not decrease, but tumor cell proliferation and microvessel density decreased. With the two drugs in combination, both stromal reaction and tumor cell proliferation decreased and apoptosis of tumor cells increased, resulting in remarkable inhibition of tumor growth at both the orthotopic and the metastatic site. Concurrent inhibition of tumor cells and activated stromal cells by a PDGF-R tyrosine kinase inhibitor and an mTOR inhibitor used in combination may represent a novel therapeutic approach for colorectal cancer.

Abstract 146: Combining molecular targeted drugs to inhibit both cancer cells and activated stromal cells in colon cancer

Recent studies have shown that tumor growth and metastasis are not determined by cancer cells alone but also by a variety of stromal cells. We have shown previously that platelet-derived growth factor receptors (PDGF-Rs) are overexpressed by various stromal cell populations, but not by cancer cells themselves in human colon cancer tissues. Blockade of PDGF-R signaling pathways in tumor-associated stromal cells has been shown to inhibit the stromal reaction. Activation of phosphoinositide 3-kinase (PI3K)/Akt/ mammalian target of rapamycin (mTOR) signaling is frequently observed in many cancer types and has been implicated in the pathogenesis of various diseases. mTOR is a central regulatory kinase that increases the production of proteins that stimulate key cellular processes such as cell proliferation, metabolism, survival, and angiogenesis. However, the effects of mTOR inhibitors on the stromal component of tumor tissues have not been studied.

In the present study, the effects of nilotinib (PDGF-R tyrosine kinase inhibitor) and everolimus (mTOR inhibitor) on tumor development and metastasis, were examined using orthotopic and experimental liver metastatic models of human colon cancer, whereby KM12SM cells were implanted into the cecum and spleen of nude mice, respectively. Groups of mice received saline (control), nilotinib (100mg/kg/day) or everolimus (1mg/kg/day), or a combination of nilotinib (100mg/kg/day) and everolimus (1mg/kg/day) by daily oral gavage. After 4 weeks of treatment, primary tumors and metastatic lesions were resected, and specimens were analyzed histologically and immunohistochemically for comparison between the treatment group and control group.

After treatment with nilotinib, the stromal reaction was significantly decreased. After treatment with everolimus, the stromal reaction was not decreased, but tumor cell proliferation and microvessel density were decreased. With the combination therapy, both tumor cell proliferation and the stromal reaction were decreased and apoptosis of tumor cells was increased, resulting in a remarkable decrease in tumor size and the number of metastatic liver lesions.

Therefore, concurrent inhibition of tumor cells and activated stromal cells by combination therapy may represent a novel molecular-targeted approach for patients with colon cancer.

Citation Format: Ryo Yuge, Yasuhiko Kitadai, Kei Shinagawa, Mieko Onoyama, Yuichiro Tanaka, Shinji Tanaka, Wataru Yasui, Kazuaki Chayama. Combining molecular targeted drugs to inhibit both cancer cells and activated stromal cells in colon cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 146. doi:10.1158/1538-7445.AM2014-146