Robotic extraperitoneal stoma closure with left hemicolectomy for descending colon cancer following abdominoperineal resection: A case report.

Extraperitoneal colostomy is often selected to reduce the risk of parastomal hernia. However, its closure surgery is rare and seldom reported. Here, we report our unique experience with robotic left hemicolectomy and extraperitoneal colostomy closure. An 83-year-old female was diagnosed with descending colon cancer with stenosis. She had previously undergone abdominoperineal resection with extraperitoneal colostomy. After improving the intestinal obstruction with a self-expanding stent, we performed robotic left hemicolectomy and extraperitoneal colostomy closure. Thanks to the multijoint function of the robot, which enables the forceps to be angled up to 90° in all directions, we could dissect the stoma from the abdominal wall up to just beneath the rectus abdominis in an intra-abdominal procedure without enlarging the skin incision. This case suggests that robotic surgery with the articulating function is beneficial for procedures near the abdominal wall ceiling and effective for extraperitoneal colostomy closure.

Visualization of cecal tumor by near-infrared laparoscopy and intraoperative colonoscopy.

BACKGROUND: In laparoscopic colorectal surgery, accurate localization of a tumor is essential for ensuring an adequate ablative margin. Therefore, a new method, near-infrared laparoscopy combined with intraoperative colonoscopy, was developed for visualizing the contour of a cecal tumor from outside of the bowel. The method was used after it was verified on a model that employed a silicone tube. CASE PRESENTATION: The patient was a 77-year-old man with a cecal tumor near the appendiceal orifice. Laparoscopy was used to clamp of the terminal ileum, and a colonoscope was then inserted through the anus to the cecum. The laparoscope in the normal light mode could not be used to identify the cecal tumor. However, a laparoscope in the near-infrared ray mode could clearly visualize the contour of the cecal tumor from outside of the bowel, and the tumor could be safely resected by a stapler. The histopathological diagnosis of the resected specimen was adenocarcinoma with an invasion depth of M and a clear negative margin. CONCLUSIONS: This is the first report of the laparoscopic detection of the contour of a cecal tumor from outside the bowel. This technique is useful and safe for contouring tumors in laparoscopic colorectal surgery and can be used in various surgeries that combine endoscopy and laparoscopy.

Development of aids to relieve vulvodynia during the postpartum period.

Postpartum women live with a low quality of life due to pain caused by episiotomy and perineal laceration. In particular, they endure pain when sitting for long periods of time to breastfeed. The purpose of this study is to develop a sitting aid to alleviate postpartum vulvodynia. This study was conducted in the following four phases from July 2017 to May 2019. They are: material selection and molding, cleaning and disinfection testing, pressure distribution measurement testing, and trial testing by postpartum women. The main material was a 100% polypropylene object with a three-dimensional reticular fiber spring structure and fiber density of 3.8 kg/m2. As a result, a sitting aid that withstands washing and disinfection well in the medical field and is breathable. It had moderate resilience and elasticity and reduced pressure on the seating surface for women weighing approximately 45 kg and 55 kg, but we were skeptical about its use for women weighing more than that. The completed sitting aid is noninvasively effective in improving the quality of life of many postpartum women, but the density and thickness of the main material should be reexamined to meet the needs of women in a wider weight range. In addition, a self-administered questionnaire survey of trial users revealed that some women did not experience relief from vulvodynia even after using the sitting aid. Such women also had physical problems such as discomfort in the lower back, difficulty breastfeeding, and difficulty standing up. For women with multiple physical problems, individual causes should be addressed.

Unanticipated pathological clearance in two cases of clinical T4b dMMR/MSI-h advanced colorectal cancer: the potential of immune checkpoint inhibitors despite positive positron-emission tomography results.

BACKGROUND: The standard treatment for colorectal cancer consists of surgery and chemotherapy, which can be combined to improve outcomes. Immune checkpoint inhibitors (ICI) are a significant advancement in the standard treatment of metastatic, unresectable colorectal cancer with deficient mismatch repair (dMMR). However, limited data are available about the use of ICI in the neoadjuvant and conversion settings. Here, we present two cases treated with ICI. CASE PRESENTATION: Case 1: A 75-year-old male with a large, borderline resectable rectal cancer diagnosed as cT4bN1bM0 who underwent neoadjuvant chemotherapy, followed by combination ICI consisting of ipilimumab and nivolumab. After four courses of ICI, the tumor significantly shrank, but positron emission tomography still showed a positive result and R0 resection was performed. Pathological analysis revealed no residual cancer cells. The patient has been monitored without adjuvant chemotherapy, and no recurrences have occurred after one year. Case 2: A 60-year-old male with locally advanced sigmoid colon cancer who received neoadjuvant treatment with pembrolizumab. The tumor partially shrank after three courses, and continued pembrolizumab monotherapy resulted in further tumor shrinkage which still showed positive positron emission tomography. Curative sigmoidectomy with partial resection of the ileum and bladder was performed, and the pathological outcome was pCR. There was no viable tumor in the specimen. The patient has been monitored without adjuvant chemotherapy for six months, and no recurrence has been observed. CONCLUSIONS: The present study reports two cases, including a large, borderline resectable rectal cancer after failure of chemotherapy followed by combination treatment with nivolumab and ipilimumab and one case of sigmoid colon cancer after pembrolizumab treatment, which resulted in pathological complete response. However, it remains unknown whether ICI therapy can replace surgery or diminish the optimal extent of resection, or whether adjuvant chemotherapy is needed after surgery in the case of achieving pCR after ICI therapy. Overall, this case report suggests that ICI before colorectal surgery can be effective and potentially a 'watch-and-wait" strategy could be used for cases in which ICI is effective.

Suctionable Gauze Ball Operated by the Console Surgeon Overcomes Wet Scenes during Robotic Rectal Surgery.

Although robotic rectal resections are now widely performed, there are few robotic suction tools that can be easily used by console surgeons. It can therefore be difficult to maintain a clear visual field in the pelvis when there is effusion and bleeding from either a highly advanced cancer or from preoperative cancer treatment. In this report, we introduce our unique surgical technique that uses a soft catheter with a small gauze ball attached, inserted through the assistant port. This simple and inexpensive "instrument" can be used by the console surgeon as a retractor as well as a reliable suction device to secure their view of the operative field in the pelvis. This technique can be used in a narrow surgical field and does not rely on an assistant surgeon, making it potentially applicable to all types of surgery.

Factors Related to Satisfaction with Decision-making Regarding Human Papillomavirus Vaccination Behavior among Female University Students in Japan.

Introduction: Cervical cancer is the fourth most common cancer among women worldwide. Most cervical cancers are caused by persistent infection with human papillomavirus (HPV) acquired through sexual contact. Decision-making is the process of choosing among several options, and a better decision is one that the people engaged in the decision-making process express satisfaction with. Despite that HPV infection is associated with sexual behavior, no studies in Japan on HPV vaccination decision-making that include perspectives on sexuality exist. This study aimed to determine the factors that influence satisfaction with decision-making concerning HPV vaccination among female university students in Japan. Methods: The cross-sectional study was carried out by an anonymous self-administered questionnaire mail survey of 1988 female university students in Japan between April and July 2021. Of them, 301 agreed to participate in the survey. After the exclusion of those with missing data, the analysis included 252 (12.7%) students. We summarized descriptive statistics in terms of characteristics, satisfaction with decision-making regarding HPV vaccination, HPV vaccination behavior, knowledge, attitude about HPV vaccination, influencing factors, and perceptions and behaviors related to sexuality. Furthermore, we conducted multivariate analyses to investigate factors that influence satisfaction with decision-making regarding HPV vaccination. Results: Of the 252 participants, 102 (40.5%) were satisfied with their decisions regarding HPV vaccination. After adjustment for confounding factors, the multivariable-adjusted odds ratios (95% confidence intervals) for factors associated with satisfaction in decision-making regarding HPV vaccination were as follows: being vaccinated (vs. non-vaccinated) 5.46 (2.51-11.89), having high knowledge scores (vs. per 1 point) 1.09 (1.01-1.17), and having awareness about the risk of contracting sexually transmitted infections (STIs) via sexual intercourse (vs. per 1 point) 0.83 (0.72-0.96). Conclusions: Being vaccinated, having higher knowledge scores, and having lower awareness regarding the risk of STIs were associated with satisfied decision-making concerning HPV vaccination. Providing younger people with correct information about cervical cancer, HPV vaccines, and STI prevention contributes to increased satisfaction with their HPV vaccination decisions.

[A Case of Transverse Colon Cancer with Gastrointestinal Amyloidosis Prevented from Anastomotic Leakage by Multidimensional Approach].

The patient was a 68-year-old woman who was on hemodialysis due to systemic amyloidosis and nephrotic syndrome. Biopsy revealed amyloid deposition in the stomach, duodenum, and colon. A transverse colon tumor was found on a follow- up CT after the aortic dissection surgery. We performed lower gastrointestinal endoscopy and contrast-enhanced CT and diagnosed transverse colon cancer with gastric wall infiltration(cStage Ⅲc). We considered that transverse colon resection was oncologically sufficient. However, due to concurrent gastrointestinal amyloidosis, which increased the risk of anastomotic leakage we performed laparoscopic extended right hemicolectomy to avoid colon-colon anastomosis with partial gastrectomy. Additionally intraoperative indocyanine green(ICG)fluorescence imaging showed that the fluorescence signal in the small intestinal wall was satisfactory, while it was weak in the colon wall. As a result, we suspected of impaired blood flow of colon wall due to an amyloidosis, so we additionally created a loop ileostomy. It is said that gastrointestinal amyloidosis raises the risk of anastomotic leakage. A case of transverse colon cancer complicated by gastrointestinal amyloidosis in which we successfully prevented anastomotic leakage through a multidimensional evaluation and approach is reported, along with a literature review.

"Role-sharing surgery": a new surgical education system that gives beginner surgeons more chances to operate while ensuring the surgical quality of robotic surgery.

It has been pointed out that robotic surgery is more time-consuming than laparoscopic surgery, and a major challenge for the future is educating young surgeons while maintaining the surgical quality. To solve these problems, we report a role-sharing surgery (RSS) approach in which the surgery is divided into several areas and timetabled, with roles shared by several operators. We performed RSS for 19 standard colorectal cancer surgeries. The surgery was completed within + 28 min of the scheduled operation time, and a beginner robotic surgeon (BRS) was able to perform approximately 66% of the total surgery. There were no statistically significant differences in the short-term outcomes between the RSS and conventional surgery groups. Based on these findings, RSS has the potential to be the best practice for educating BRSs in robotic surgery, the use of which is expected to increase steadily in the future.

Hepatitis B Virus-related Membranous Nephropathy with Crescentic Formation in an Inactive Carrier of Positive Hepatitis B Surface Antigen with Undetectable DNA under Anti-viral Treatment.

A man who was an inactive hepatitis B virus (HBV) carrier with positive hepatitis B surface antigen (HBs antigen) and undetectable HBV-DNA under anti-viral treatment developed nephrotic syndrome at 52 years old, and a renal biopsy revealed advanced membranous nephropathy (MN) with focal cellular crescents, interstitial hemorrhaging, and peritubular capillaritis. Immunofluorescence studies demonstrated granular IgG deposition and HBs antigen-positivity along the capillaries. Glomeruli were negative for phospholipase A2 receptor 1. There were no clinical findings of systemic vasculitis. We considered MN combined with small-vessel vasculitis due to HBV infection. These results suggest that HBV-related kidney disease should be considered even in patients with an inactive HBV carrier status under treatment.

Spontaneous regression of advanced transverse colon cancer with deficient mismatch repair: a case report.

BACKGROUND: Spontaneous regression (SR) of cancer occurs in 1 in 60,000-100,000 patients. This phenomenon has been reported in almost all cancer types, most commonly neuroblastoma, renal cell carcinoma, malignant melanoma, and lymphoma/leukemia. However, SR in colorectal cancer (CRC) is extremely rare, particularly in advanced cases. Hence, this report describes a very rare case of spontaneous regression of advanced transverse colon cancer. CASE PRESENTATION: A 76-year-old female with anemia was diagnosed with a type II well-differentiated adenocarcinoma in the middle transverse colon. Two months later, a second colonoscopy examination was performed for preoperative marking, and it revealed tumor shrinkage and a shift to type 0-IIc morphology. Endoscopic tattooing was then performed, followed by a laparoscopic partial resection of the transverse colon with D3 lymph node dissection. However, the resected specimen contained no tumor, and colonoscopy showed no tumor remnants in the remaining colon. Histopathological examination revealed mucosal regeneration and a mucus nodule in between the submucosal and muscular layers, with no cancer cells detected. Immunohistochemical analysis revealed the loss of MutL homolog 1 (MLH1) and postmeiotic segregation increased 2 (PMS2) expression in the cancer cells of biopsied specimens, suggesting deficient mismatch repair (dMMR). The patient continues to be followed up until 6 years postoperatively, and no recurrence has been observed. In this study, we also reviewed similar reported cases of spontaneous regression of cancer involving dMMR. CONCLUSION: This study presents a rare case of spontaneous regression of advanced transverse colon cancer wherein dMMR is strongly involved. However, further accumulation of similar cases is needed to elucidate this phenomenon and to develop new treatment strategies for CRC.

Enhancement of Neprilysin Activity by Natural Polyphenolic Compounds and Their Derivatives in Cultured Neuroglioma Cells.

The onset of Alzheimer's disease (AD) is characterized by accumulation of amyloid ß peptide (Aß) in the brain. Neprilysin (NEP) is one of the major Aß-degrading enzymes. Given findings that NEP expression in the brain declines from the early stage of AD before apparent neuronal losses are observed, enhancement of NEP activity and expression may be a preventive and therapeutic strategy relevant to disease onset. We screened for compounds that could enhance the activity and expression of NEP using a polyphenol library previously constructed by our research group and investigated the structure-activity relationships of the identified polyphenols. We found that amentoflavone, apigenin, kaempferol, and chrysin enhanced the activity and expression of NEP, suggesting that chemical structures involving a double bond between positions 2 and 3 in the C ring of flavones are important for NEP enhancement, while catechol or pyrogallol structures, except for the galloyl group of catechins, abolished these effects. Moreover, natural compounds, such as quercetin, were not effective per se, but were changed to effective compounds by adding a lipophilic moiety. Using our study findings, we propose improvements for dietary habits with experimental evidence, and provide a basis for the development of novel small molecules as disease-modifying drugs for AD.

AZD6738 promotes the tumor suppressive effects of trifluridine in colorectal cancer cells.

Ataxia telangiectasia and Rad3­related (ATR) is a kinase that repairs DNA damage. Although inhibitors that selectively target ATR have been developed, their effectiveness in colorectal cancer has not been widely reported. The present study hypothesized that anticancer agents that effectively act in the S phase before the G2/M checkpoint may be ideal agents for concomitant use with ATR inhibitors, which act at the G2/M checkpoint. Therefore, the present study examined the combined effects of AZD6738, an ATR inhibitor, and trifluridine (FTD), which acts in the S phase and has a high DNA uptake rate. In vitro cell viability assays, flow cytometry and western blotting were performed to evaluate cell viability, and changes in cell cycle localization and protein expression. The results revealed that in colorectal cancer cells, the combination of AZD6738 and FTD inhibited cell viability, cell cycle arrest at the G2/M checkpoint and Chk1 phosphorylation, and increased apoptotic protein expression levels more than that when treated with FTD alone. HT29, a BRAF­mutant cell line known to be resistant to anticancer drugs, was used to induce tumors in vivo. Since FTD does not have sufficient efficacy when administered orally, it was mixed with tipiracil to prevent degradation; this mixture is known as TAS­102. TAS­102 alone exerted minimal tumor suppressive effects; however, when used in combination with AZD6738, tumor suppression was observed, suggesting that AZD6738 may increase the effectiveness of a weakly effective drug. Although ATR inhibitors are effective against p53 mutants, the present study demonstrated that these inhibitors were also effective against the p53 wild­type HCT116 colorectal cancer cell line. In conclusion, combination therapy with AZD6738 and FTD enhanced the inhibition of tumor proliferation in vitro and in vivo. In the future, we aim to investigate the potentiating effect of AZD6738 on 5­fluouracil­resistant cell lines that are difficult to treat.

Alterations of ATG4A and LC3B in neurons derived from Alzheimer's disease patients.

We investigated the alterations in autophagy-related molecules in neurons differentiated from induced pluripotent stem cells obtained from patients with Alzheimer's disease (AD). Consistent with our previous microarray data, ATG4A protein was upregulated in the neurons derived from a familial AD patient with an APP-E693Δ mutation who showed accumulation of intracellular amyloid ß peptide (Aß). This upregulation was reversed by inhibiting Aß production, suggesting that the intracellular Aß may be responsible for the upregulation of ATG4A. The LC3B-II/LC3B-I ratio, an index of autophagosome formation, was lower in the neurons derived from the AD patient with APP-E693Δ as well as the neurons derived from other familial and sporadic AD patients. These findings indicate that dysregulation of autophagy-related molecules may accelerate the pathogenesis of AD.

Inter-organ Wingless/Ror/Akt signaling regulates nutrient-dependent hyperarborization of somatosensory neurons.

Nutrition in early life has profound effects on an organism, altering processes such as organogenesis. However, little is known about how specific nutrients affect neuronal development. Dendrites of class IV dendritic arborization neurons in Drosophila larvae become more complex when the larvae are reared on a low-yeast diet compared to a high-yeast diet. Our systematic search for key nutrients revealed that the neurons increase their dendritic terminal densities in response to a combined deficiency in vitamins, metal ions, and cholesterol. The deficiency of these nutrients upregulates Wingless in a closely located tissue, body wall muscle. Muscle-derived Wingless activates Akt in the neurons through the receptor tyrosine kinase Ror, which promotes the dendrite branching. In larval muscles, the expression of wingless is regulated not only in this key nutrient-dependent manner, but also by the JAK/STAT signaling pathway. Additionally, the low-yeast diet blunts neuronal light responsiveness and light avoidance behavior, which may help larvae optimize their survival strategies under low-nutritional conditions. Together, our studies illustrate how the availability of specific nutrients affects neuronal development through inter-organ signaling.

Evaluation of long-term chronic pain and outcomes for unilateral vs bilateral circular incision transabdominal preperitoneal inguinal hernia repair.

Aim: This study has two aims: to evaluate long-term chronic pain and complications after circular incision transabdominal preperitoneal inguinal hernia repair (C-TAPP) and compare outcomes of unilateral and bilateral inguinal hernia cases. Methods: A postoperative patient questionnaire was used to evaluate pain and complications in 1546 patients who underwent C-TAPP for simple inguinal hernia. Questions concerned satisfaction with surgery, pain at rest, pain at movement, mesh discomfort on a 10-point scale, and complications, such as recurrence. Patients were classified into unilateral (U Group) and bilateral (B Group) groups, and propensity score matching was performed to compare long-term chronic pain and complications. Results: The questionnaire return rates were 77.5% (1034 cases) and 79.9% (135 cases) in unilateral and bilateral cases. The frequency of moderate-to-severe (≥4 points) pain at rest, pain at movement, and mesh discomfort were 3.2%, 3.6%, and 4.5%, respectively. After propensity score matching, no significant differences in pain at rest (P = .726), at movement (P = .712), or mesh discomfort (P = .981) were detected between the U and B groups. Postoperative complications occurred in 2.1% of all patients, and the recurrence rate was 0.3%. In the post-match comparison, no differences in complications with Clavian-Dindo classification ≥III (U Group 0.7%, B Group 2.1%, P = .622) were detected. Conclusion: C-TAPP, which focuses on the layered structure, showed acceptable results for long-term chronic pain. Bilateral cases did not have worse pain or complications compared to unilateral cases.

Difficulty in predicting intra-abdominal adhesion before cesarean section: A case report.

Severe adhesions between the bladder and uterus necessitated an atypical incision in the cesarean section of a woman with endometriosis. This could not be predicted with pre-surgery MRI. No methods in the literature are able to predict adhesions with true certainty; it is therefore still difficult to diagnose intra-abdominal adhesions.

Robot-assisted laparoscopic abdominoperineal resection with en bloc prostatectomy using the Retzius-sparing robot-assisted radical prostatectomy technique.

INTRODUCTION: The best surgical technique for rectal cancer invading the prostate remains controversial. Rectal resection with en bloc prostatectomy using a standard retropubic approach is an option but has disadvantages. We report a new surgical procedure applying Retzius-sparing robot-assisted radical prostatectomy. MATERIALS AND SURGICAL TECHNIQUE: First, the rectum was mobilized mainly at its dorsal side. Next, the prostate was separated from the bladder and urethra via the pouch of Douglas approach without opening the Retzius cavity, after which the surgical specimen was extracted through the perineal wound. Lateral pelvic lymph node dissection was performed after vesicourethral anastomosis. DISCUSSION: This new robotic procedure minimizes surgical trauma and preserves normal pelvic anatomy. Furthermore, this approach makes it easy to perform subsequent lateral pelvic lymph node dissection.

ATR inhibitor AZD6738 increases the sensitivity of colorectal cancer cells to 5­fluorouracil by inhibiting repair of DNA damage.

The repair of DNA damage caused by chemotherapy in cancer cells occurs mainly at two cell cycle checkpoints (G1 and G2) and is a factor contributing to chemoresistance. Most colorectal cancers harbor mutations in p53, the main pathway involved in the G1 checkpoint, and thus, are particularly dependent on the G2 checkpoint for DNA repair. The present study examined the effect of AZD6738, a specific inhibitor of ataxia telangiectasia mutated and rad3­related (ATR) involved in the G2 checkpoint, combined with 5­fluorouracil (5­FU), a central chemotherapeutic agent, on colorectal cancer cells. Since 5­FU has a DNA­damaging effect, its combination with AZD6738 is likely to enhance the therapeutic effect. The effects of the AZD6738/5­FU combination were evaluated in various colorectal cancer cells (HT29, SW480, HCT116 and DLD­1 cells) by flow cytometry (HT29 cells), western blotting (HT29 cells) and water­soluble tetrazolium 1 assays (HT29, SW480, HCT116 and DLD­1 cells), as well as in an experimental animal model (HT29 cells). In vitro, the AZD6738/5­FU combination increased the number of mitotic cells according to flow cytometry, decreased the checkpoint kinase 1 phosphorylation levels and increased cleaved caspase­3 and phosphorylated form of H2A.X variant histone levels according to western blotting, and decreased the proliferation rate of four colon cancer cell lines according to cell viability experiments. In vivo, xenografted colorectal cancer cells treated with the AZD6738/5­FU combination exhibited a marked decrease in proliferation compared with the 5­FU alone group. The present results suggested that AZD6738 enhanced the effect of 5­FU in p53­mutated colorectal cancer.

The Interaction Between Cancer-associated Fibroblasts and Cancer Cells Enhances Bcl-xL and Mcl-1 in Colorectal Cancer.

BACKGROUND/AIM: The acquisition of resistance to apoptosis is one of the biggest problems in colorectal cancer (CRC) treatment. This study aimed to elucidate the mechanisms of resistance to apoptosis with a focus on interleukin (IL)-6 produced by the interaction between cancer cells and cancer-associated fibroblasts (CAFs). MATERIALS AND METHODS: DLD-1 and HCT116 cell lines were treated with IL-6 and furthermore co-cultured with CAFs. The expression levels of Bcl-xL, Mcl-1 and phosphorylation of STAT3 were evaluated by western blotting. We also performed immunostaining for CRC specimens and evaluated the correlation between CAFs invasion and Bcl-xL/Mcl-1 expression. RESULTS: Both IL-6 and co-culturing enhanced Bcl-xL, Mcl-1 and the phosphorylation of STAT3. Immunohistochemistry showed a positive correlation between CAFs and Bcl-xL/Mcl-1. These results showed that the interaction between CAFs and cancer cells enhances Bcl-xL and Mcl-1 through the IL-6/STAT3 signaling pathway. CONCLUSION: Our findings provide new potential therapeutic targets and strategies for CRC treatment.

Chitinase 3-like 1 secreted from cancer-associated fibroblasts promotes tumor angiogenesis via interleukin-8 secretion in colorectal cancer.

The cancer­stromal interaction has been demonstrated to promote tumor progression, and cancer-associated fibroblasts (CAFs), which are the main components of stromal cells, have attracted attention as novel treatment targets. Chitinase 3-like 1 (CHI3L1) is a chitinase-like protein, which affects cell proliferation and angiogenesis. However, the mechanisms through which cells secrete CHI3L1 and through which CHI3L1 mediates tumor progression in the cancer microenvironment are still unclear. Accordingly, the present study assessed the secretion of CHI3L1 in the microenvironment of colorectal cancer and evaluated how CHI3L1 affects tumor angiogenesis. CAFs and normal fibroblasts (NFs) established from colorectal cancer tissue, and human colon cancer cell lines were evaluated using immunostaining, cytokine antibody array, RNA interference, reverse transcription-quantitative PCR (RT-qPCR), ELISA, western blotting and angiogenesis assays. The expression and secretion of CHI3L1 in CAFs were stronger than those in NFs and colorectal cancer cell lines. In addition, interleukin-13 receptor α2 (IL-13Rα2), a receptor for CHI3L1, was not expressed in colorectal cancer cell lines, but was expressed in fibroblasts, particularly CAFs. Furthermore, the expression and secretion of IL-8 in CAFs was stronger than that in NFs and cancer cell lines, and recombinant CHI3L1 addition increased IL-8 expression in CAFs, whereas knockdown of CHI3L1 suppressed IL-8 expression. Furthermore, IL-13Rα2 knockdown suppressed the enhancement of IL-8 expression induced by CHI3L1 treatment in CAFs. For vascular endothelial growth factor-A (VEGFA), similar results to IL-8 were observed in an ELISA for comparison of secretion between CAFs and NFs and for changes in secretion after CHI3L1 treatment in CAFs; however, no significant differences were observed for changes in expression after CHI3L1 treatment or IL-13Rα2 knockdown in CAFs assessed using RT-qPCR assays. Angiogenesis assays revealed that tube formation in vascular endothelial cells was suppressed by conditioned medium from CAFs with the addition of human CHI3L1 neutralizing antibodies compared with control IgG, and also suppressed by conditioned medium from CAFs transfected with CHI3L1, IL-8 or VEGFA small interfering RNA compared with negative control small interfering RNA. Overall, the present findings indicated that CHI3L1 secreted from CAFs acted on CAFs to increase the secretion of IL-8, thereby affecting tumor angiogenesis in colorectal cancer.