Downregulation of ABCC3 activates MAPK signaling through accumulation of deoxycholic acid in colorectal cancer cells.

ABCC3 (also known as MRP3) is an ATP binding cassette transporter for bile acids, whose expression is downregulated in colorectal cancer through the Wnt/ß-catenin signaling pathway. However, it remained unclear how downregulation of ABCC3 expression contributes to colorectal carcinogenesis. We explored the role of ABCC3 in the progression of colorectal cancer-in particular, focusing on the regulation of bile acid export. Gene expression analysis of colorectal adenoma isolated from familial adenomatous polyposis patients revealed that genes related to bile acid secretion including ABCC3 were downregulated as early as at the stage of adenoma formation. Knockdown or overexpression of ABCC3 increased or decreased intracellular concentration of deoxycholic acid, a secondary bile acid, respectively, in colorectal cancer cells. Forced expression of ABCC3 suppressed deoxycholic acid-induced activation of MAPK signaling. Finally, we found that nonsteroidal anti-inflammatory drugs increased ABCC3 expression in colorectal cancer cells, suggesting that ABCC3 could be one of the targets for therapeutic intervention of familial adenomatous polyposis. Our data thus suggest that downregulation of ABCC3 expression contributes to colorectal carcinogenesis through the regulation of intracellular accumulation of bile acids and activity of MAPK signaling.

Long-term survival and functional outcomes of laparoscopic surgery for clinical stage I ultra-low rectal cancers located within 5 cm of the anal verge: A prospective phase II trial (Ultimate trial).

OBJECTIVE: To clarify the long-term oncological outcomes and postoperative anal, urinary, and sexual functions after laparoscopic surgery for clinical stage I very low rectal carcinoma located near the anal canal. SUMMARY BACKGROUND DATA: Laparoscopic surgery is widely applied for rectal cancer; however, concerns remain, with some studies showing poorer outcomes compared to open surgery. METHODS: This single-arm, phase II trial included patients registered preoperatively from 47 institutions in Japan. The planned sample size was 300. The primary endpoint was the 3-year local recurrence rate. Anal, urinary, and sexual functions were evaluated using a prospective questionnaire. RESULTS: Three-hundred patients were registered between January 2014 and March 2017. Anus-preserving surgery was performed in 278 (93%), including 172 who underwent intersphincteric resection (58%) and 106 (36%) who underwent low anterior resection. The 3-year cumulative local recurrence rate was 6.3%. At 3 years postoperatively, 87% of patients used their own anus, and the median incontinence score improved from 12 at 3 months to 8 at 3 years. Only 5% of patients had severe incontinence (incontinence score of 16 points). Postoperative urinary function evaluation showed that International Prostate Symptom Score and Overactive Bladder Symptom Score decreased 1 week after surgery, but recovered to preoperative level 1 month after surgery. International Consultation on Incontinence Questionnaire-Sort Form remained almost stable after surgery. Sexual function evaluation using the International Index of Erectile Function-5 and International Index of Erectile Function-15 revealed that the patients had deteriorated 3 months after surgery but had recovered only slightly by 6 months. CONCLUSIONS: Laparoscopic surgery achieves feasible long-term oncological outcomes and a high rate of anus preservation with moderate anal function, and an acceptable incontinence score. While urinary function recovered rapidly, sexual function showed poor recovery.

Prospective Multicenter Comprehensive Survey on Male Sexual Dysfunction following Laparoscopic, Robotic, and Transanal Approaches for Rectal Cancer (the LANDMARC Study).

OBJECTIVE: To investigate the incidence of male sexual dysfunction (SD) including erectile dysfunction (ErD) and ejaculatory dysfunction (EjD) after minimally invasive rectal cancer surgery. BACKGROUND: Male SD significantly affects post-rectal cancer surgery quality of life (QOL). Current assessments using the International Index of Erectile Function-5 are unsuitable for patients with reduced postoperative sexual activity, because it assumes sexual intercourse. This study addresses this gap using the Erection Hardness Score (EHS) and custom ejaculatory questionnaires. METHODS: This prospective multicenter open-label phase II trial enrolled 399 patients who underwent laparoscopic (Lap), robotic (Ro), or transanal (Ta) rectal cancer surgery. EHS and custom ejaculatory questionnaires assessed ErD, EjD, and potency impairment at 3, 6, and 12 months postoperatively. The rates were assessed in the full analysis set and compared between the Lap and Ro groups after propensity score matching. RESULTS: At 12 months, the overall incidences of ErD and EjD were 34.7% and 29.8%, respectively. The Ro group showed a significantly lower EjD rate (25.0%) than the Lap group (40.9%), with no significant difference in ErD. Potency impairment was lower in the Ro group at 6 months (32.7% vs. 22.3%) and 12 months (29.0% vs. 17.8%) postoperatively. The Ta group showed relatively high ErD and EjD at 3 months, with some recovery at 12 months. CONCLUSIONS: Minimally invasive rectal cancer surgery commonly results in ErD, EjD, and potency impairment. Robotic surgery provides lower EjD rates and less potency impairment. Comprehensive sexual function assessments are essential to inform patients and improve QOL outcomes.

How Does Omitting Additional Surgery After Local Excision Affect the Prognostic Outcome of Patients With High-risk T1 Colorectal Cancer?

OBJECTIVE: To investigate how omitting additional surgery after local excision (LE) affects patient outcomes in high-risk T1 colorectal cancer (CRC). BACKGROUND: It is debatable whether additional surgery should be performed for all patients with high-risk T1 CRC regardless of the tolerability of invasive procedures. METHODS: Patients who had received LE for T1 CRC at the Japanese Society for Cancer of the Colon and Rectum institutions between 2009 and 2016 were analyzed. Those who had received additional surgical resection and those who did not were matched one-on-one by the propensity score-matching method. A total of 401 propensity score-matched pairs were extracted from 1975 patients at 27 Japanese Society for Cancer of the Colon and Rectum institutions and were compared. RESULTS: Regional lymph node metastasis was observed in 31 (7.7%) patients in the LE + surgery group. Comparatively, the incidence of oncologic adverse events was low in the LE-alone group, such as the 5-year cumulative risk of local recurrence (4.1%) or overall recurrence (5.5%). In addition, the difference in the 5-year cancer-specific survival between the LE + surgery and LE-alone groups was only 1.8% (99.7% and 97.9%, respectively), whereas the 5-year overall survival was significantly lower in the LE-alone group than in the LE + surgery group [88.5% vs 94.5%, respectively ( P = 0.002)]. CONCLUSIONS: Those who had decided to omit additional surgery at the dedicated center for CRC treatment presented a small number of oncologic events and a satisfactory cancer-specific survival, which may suggest an important role of risk assessment regarding nononcologic adverse events to achieve a best practice for each individual with high-risk T1 tumors.

Calreticulin exposure induced by anticancer drugs is associated with the p53 signaling pathway in colorectal cancer cells.

Immunogenic cell death (ICD) enhances immunogenicity and activates antitumor immune responses. ICD induction by anticancer drugs may be effective against microsatellite-stable colorectal cancers (CRCs) that are less responsive to immune checkpoint inhibitors. Calreticulin (CRT) is crucial in ICD, promoting dendritic cell phagocytosis and initiating antitumor immunity. This study investigated CRT exposure mechanisms in four CRC cell lines and three human CRC organoids. Flow cytometry and immunofluorescence showed that oxaliplatin and 5-fluorouracil caused CRT exposure in all models. Despite CRT's association with endoplasmic reticulum stress, Western blot analysis showed no increase in this stress. These findings suggest alternative pathways. RNA sequencing identified enrichment of p53 signaling pathway genes, including TP53I3, TP53INP1, and YPEL3, which were confirmed by RT-qPCR. These results suggest that the p53 signaling pathway plays an important role in CRT exposure induced by anticancer drugs.

Long-Term Outcomes of Additional Surgery After Endoscopic Resection Versus Primary Surgery for T1 Colorectal Cancer.

INTRODUCTION: There is considerable concern about whether endoscopic resection (ER) before additional surgery (AS) for T1 colorectal cancer (CRC) has oncologically potential adverse effects. Therefore, the aim of this study was to compare the long-term outcomes, including overall survival (OS), of patients treated with AS after ER vs primary surgery (PS) for T1 CRC using a propensity score-matched analysis from a large observational study. METHODS: This study investigated 6,105 patients with T1 CRC treated with either ER or surgical resection between 2009 and 2016 at 27 high-volume Japanese institutions, with those undergoing surgery alone included in the PS group and those undergoing AS after ER included in the AS group. Propensity score matching was used for long-term outcomes of mortality and recurrence analysis. RESULTS: After propensity score matching, 1,219 of 2,438 patients were identified in each group. The 5-year OS rates in the AS and PS groups were 97.1% and 96.0%, respectively (hazard ratio: 0.72, 95% confidence interval: 0.49-1.08), indicating the noninferiority of the AS group. Moreover, 32 patients (2.6%) in the AS group and 24 (2.0%) in the PS group had recurrences, with no significant difference between the 2 groups (odds ratio: 1.34, 95% confidence interval: 0.76-2.40, P = 0.344). DISCUSSION: ER before AS for T1 CRC had no adverse effect on patients' long-term outcomes, including the 5-year OS rate. ER is a viable first-line treatment option for endoscopically resectable T1 CRC.

Treatment Decision for Locally Resected T1 Colorectal Carcinoma-Verification of the Japanese Guideline Criteria for Additional Surgery Based on Long-Term Clinical Outcomes.

INTRODUCTION: To verify the value of the pathological criteria for additional treatment in locally resected pT1 colorectal carcinoma (CRC) which have been used in the Japanese Society for Cancer of the Colon and Rectum (JSCCR) guidelines since 2009. METHODS: We enrolled 4,667 patients with pT1 CRC treated at 27 institutions between July 2009 and December 2016 (1,257 patients with local resection alone [group A], 1,512 patients with additional surgery after local resection [group B], and 1,898 patients with surgery alone [group C]). All 5 factors of the JSCCR guidelines (submucosal resection margin, tumor histologic grade, submucosal invasion depth, lymphovascular invasion, and tumor budding) for lymph node metastasis (LNM) had been diagnosed prospectively. RESULTS: Any of the risk factors were present in 3,751 patients. The LNM incidence was 10.4% (95% confidence interval 9.4-11.5) in group B/C patients with risk factors, whereas it was 1.8% (95% confidence interval 0.4-5.3) in those without risk factors ( P < 0.01). In group A, the incidence of recurrence was 3.6% in patients with risk factors, but it was only 0.4% in patients without risk factors ( P < 0.01). The disease-free survival rate of group A patients classified as risk positive was significantly worse than those of groups B and C patients. However, the 5-year disease-free survival rate in group A patients with no risk was 99.6%. DISCUSSION: Our large-scale real-world multicenter study demonstrated the validity of the JSCCR criteria for pT1 CRC after local resection, especially regarding favorable outcomes in patients with low risk of LNM.

Laparoscopic versus open colectomy for locally advanced colon cancer in obese patients: a nationwide, multicenter, propensity score-based analysis of short- and long-term outcomes.

OBJECTIVE: This study evaluated the short-and long-term outcomes of laparoscopic colectomy versus open surgery in obese patients (body mass index ≥25 kg/m2) with locally advanced colon cancer to ascertain the non-inferiority of laparoscopic surgery to open surgery. METHODS: In this large cohort study (UMIN-ID: UMIN000033529), we retrospectively reviewed prospectively collected data from consecutive patients who underwent laparoscopic or open surgery for pathological stage II-III colon cancer between 2009 and 2013. A comparative analysis was performed after propensity score matching between the laparoscopic and open surgery groups. The primary endpoint was the 3-year relapse-free survival (RFS). RESULTS: We identified 1575 eligible patients from 46 institutions. Each group comprised 526 propensity score-matched patients. Comparing the laparoscopic versus open surgery group, laparoscopic surgery was significantly associated with increased median operating time (225 vs. 192.5 min; P < .0001) and decreased median estimated blood loss (20 vs. 140 ml; P < .0001). Lymph node retrieval (20 vs. 19; P = 0.4392) and postoperative complications (4.6% vs. 5.7%; P = 0.4851) were similar, postoperative hospital stay was shorter (10 vs. 12 days; P < .0001), and the 3-year RFS rates were similar (82.8 vs. 81.2%). The hazard ratio (HR) for relapse-free survival for laparoscopic versus open surgery was 0.927 (90% confidence interval [CI], 0.747-1.150, one-sided P for non-inferiority = .001), indicating that for obese patients with colon cancer, laparoscopic surgery was non-inferior to open surgery. CONCLUSION: Laparoscopic surgery in obese patients with colon cancer offers advantages in terms of short-term outcomes and no disadvantages in terms of long-term outcomes.

Infliximab Inhibits Colitis Associated Cancer in Model Mice by Downregulating Genes Associated with Mast Cells and Decreasing Their Accumulation.

Inflammatory bowel diseases (IBDs), such as Crohn's disease or ulcerative colitis, can be treated with anti TNF-alpha (TNF-α) antibodies (Abs), but they also put patients with IBDs at risk of cancer. We aimed to determine whether the anti TNF-α Ab induces colon cancer development in vitro and in vivo, and to identify the genes involved in colitis-associated cancer. We found that TNF-α (50 ng/mL) inhibited the proliferation, migration, and invasion of HCT8 and COLO205 colon cancer cell lines and that anti TNF-α Ab neutralized TNF-α inhibition in vitro. The effects of anti TNF-α Ab, infliximab (10 mg/kg) were investigated in mouse models of colitis-associated cancer induced by intraperitoneally injected azoxymethane (AOM: 10 mg/kg)/orally administered dextran sodium sulfate (DSS: 2.5%) (AOM/DSS) in vivo. Infliximab significantly attenuated the development of colon cancer in these mice. Microarray analyses and RT-qPCR revealed that mast cell protease 1, mast cell protease 2, and chymase 1 were up-regulated in cancer tissue of AOM/DSS mice; however, those mast cell related genes were downregulated in cancer tissue of AOM/DSS mice with infliximab. These results suggested that mast cells play a pivotal role in the development of cancer associated with colitis in AOM/DSS mice.

Enhanced Clinical Utility of Molecular Budding Signature as a Recurrence Risk Determinant in Stage II and III Colon Cancer Patients.

BACKGROUND: A molecular budding signature (MBS), which consists of seven tumor budding-related genes, was recently presented as a prominent prognostic indicator in colon cancer (CC) using microarray data acquired from frozen specimens. This study aimed to confirm the predictive power of MBS for recurrence risk based on formalin-fixed, paraffin-embedded (FFPE) materials. METHODS: This research utilized the same microarray data from a prior multicenter study using FFPE whole tissue sections, which retrospectively reviewed 232 stage II CC patients without adjuvant chemotherapy and 302 stage III CC patients with adjuvant chemotherapy. All patients underwent upfront curative surgery without neoadjuvant therapy between 2009 and 2012. An MBS score was calculated using the mean of log2 [each signal] of seven genes (MSLN, SLC4A11, WNT11, SCEL, RUNX2, MGAT3, and FOXC1) as described before. RESULTS: The MBS-low group exhibited a better relapse-free survival (RFS) than the MBS-high group in stage II (P = 0.0077) and in stage III CC patients (P = 0.0003). Multivariate analyses revealed that the MBS score was an independent prognostic factor in both stage II (P = 0.0257) and stage III patients (P = 0.0022). Especially among T4, N2, or both (high-risk) stage III patients, the MBS-low group demonstrated markedly better RFS compared with the MBS-high group (P = 0.0013). CONCLUSIONS: This study confirmed the predictive power of the MBS for recurrence risk by employing FFPE materials in stage II/III CC patients.

Nomogram as a novel predictive tool for lymph node metastasis in T1 colorectal cancer treated with endoscopic resection: a nationwide, multicenter study.

BACKGROUND AND AIMS: Since 2009, the Japanese Society for Cancer of the Colon and Rectum guidelines have recommended that tumor budding and submucosal invasion depth, in addition to lymphovascular invasion and tumor grade, be included as risk factors for lymph node metastasis (LNM) in patients with T1 colorectal cancer (CRC). In this study, a novel nomogram was developed and validated by usirge-scale, real-world data, including the Japanese Society for Cancer of the Colon and Rectum risk factors, to accurately evaluate the risk of LNM in T1 CRC. METHODS: Data from 4673 patients with T1 CRC treated at 27 high-volume institutions between 2009 and 2016 were analyzed for LNM risk. To prepare a nonrandom split sample, the total cohort was divided into development and validation cohorts. Pathologic findings were extracted from the medical records of each participating institution. The discrimination ability was measured by using the concordance index, and the variability in each prediction was evaluated by using calibration curves. RESULTS: Six independent risk factors for LNM, including submucosal invasion depth and tumor budding, were identified in the development cohort and entered into a nomogram. The concordance index was .784 for the clinical calculator in the development cohort and .790 in the validation cohort. The calibration curve approached the 45-degree diagonal in the validation cohort. CONCLUSIONS: This is the first nomogram to include submucosal invasion depth and tumor budding for use in routine pathologic diagnosis based on data from a nationwide multi-institutional study. This nomogram, developed with real-world data, should improve decision-making for an appropriate treatment strategy for T1 CRC.

[A Case of an Elderly Patient Who Underwent Conversion Resection for Pancreatic Cancer with Positive Peritoneal Cytology].

We report a case of an elderly patient, 82 years-old, with initially-unresectable pancreatic head cancer, who successfully underwent complete resection of the primary lesion after systemic chemotherapy for 6 months. The patient had a history of pancreatic body-tail resection for intraductal papillary mucinous carcinoma in 2005. In 2020, a routine examination revealed an increased CA19-9 value of 1,958 U/mL and showed a pancreatic head tumor of 35 mm on CT images. Finally, the tumor was pathologically diagnosed as pancreatic cancer by a biopsied sample. Although CT images showed no distant metastasis, peritoneal lavage cytology was indicated as positivity(H0P0CY1)in the staging laparoscopy. We implanted a peritoneal port and introduced systemic chemotherapy of gemcitabine and nab-paclitaxel combination therapy. This treatment for 6 months induced tumor shrinkage to 30 mm on the CT image, normalized CA19-9 value to 22.6 U/mL, and negative cytology in the collected lavage fluid from the peritoneal port. The patient's general condition was maintained even after the chemotherapy and the lavage cytology was pathologically diagnosed as negative(H0P0CY0)in the repeated staging laparoscopy, therefore we decided to perform pancreaticoduodenectomy as a conversion surgery. The patient was discharged on the 21st postoperative day with an uneventful course and underwent adjuvant chemotherapy of S-1 for 6 months. No recurrence was found in 8 months after the surgery. In such a case of the selected elderly patient with a maintained general condition, it is feasible to undergo multimodal treatments including conversion surgery for an initially-unresectable pancreatic cancer with positive peritoneal cytology.

The Mucus Binding Factor Is Not Necessary for Lacticaseibacillus rhamnosus CRL1505 to Exert Its Immunomodulatory Activities in Local and Distal Mucosal Sites.

Both viable and non-viable orally administered Lacticaseibacillus rhamnosus CRL1505 modulate immunity in local (intestine) and distal (respiratory) mucosal sites. So, intestinal adhesion and colonization are not necessary for this probiotic strain to exert its immunomodulatory effects. In this work, a mucus-binding factor knockout CRL1505 strain (ΔmbfCRL1505) was obtained and the lack of binding ability to both intestinal epithelial cells and mucin was demonstrated in vitro. In addition, two sets of in vivo experiments in 6-week-old Balb/c mice were performed to evaluate ΔmbfCRL1505 immunomodulatory activities. (A) Orally administered ΔmbfCRL1505 prior to intraperitoneal injection of the Toll-like receptor 3 (TLR3) agonist poly(I:C) significantly reduced intraepithelial lymphocytes (CD3+NK1.1+CD8αα+) and pro-inflammatory mediators (TNF-α, IL-6 and IL-15) in the intestinal mucosa. (B) Orally administered ΔmbfCRL1505 prior to nasal stimulation with poly(I:C) significantly decreased the levels of the biochemical markers of lung tissue damage. In addition, reduced recruitment of neutrophils and levels of pro-inflammatory mediators (TNF-α, IL-6 and IL-8) as well as increased IFN-ß and IFN-γ in the respiratory mucosa were observed in ΔmbfCRL1505-treated mice when compared to untreated control mice. The immunological changes induced by the ΔmbfCRL1505 strain were not different from those observed for the wild-type CRL1505 strain. Although it is generally accepted that the expression of adhesion factors is necessary for immunobiotics to induce their beneficial effects, it was demonstrated here that the mbf protein is not required for L. rhamnosus CRL1505 to exert its immunomodulatory activities in local and distal mucosal sites. These results are a step forward towards understanding the mechanisms involved in the immunomodulatory capabilities of L. rhamnosus CRL1505.

[A Case of Laparoscopic Abdominoperineal Resection and Perineal Reconstruction for Signet-Ring Cell Carcinoma with Skin Invasion Derived from the Anal Gland].

A 56-year-old man was referred to our hospital with an awareness of anal tumor. The tumor extended from the anal verge to the back of left testicle. Colonoscopy showed no tumor in the rectum and the anal canal. Biopsy showed mucus- producing adenocarcinoma(sig), and we diagnosed anal canal adenocarcinoma with immunostaining. Laparoscopic abdominoperineal rectal resection and perineal reconstruction with the V-Y fasciocutaneous flap closure technique. The patient had no major postoperative complications, and was discharged on 23rd postoperative day. Pathological examination revealed that the tumor was pT3N0M0, pStage ⅡB. The patient received adjuvant chemotherapy with CAPOX and has survived 12 months without recurrence. Immunostaining may be used to diagnose the signet-ring cell carcinoma without tumor of anal canal. In addition, reconstruction of the perineum for large anal tumors is useful.

[Successful R0 Resection of Two Metachronous Krukenberg Tumors from Gastric Cancer-A Case Report].

A 50s woman with a stomachache was referred to our hospital with diagnosed gastric cancer. Upper endoscopy showed a type 3 tumor in the lower gastric body, and CT demonstrated a pelvic tumor 10 cm in size. Laparoscopic surgery was performed; since the pelvic tumor was found to derive from the left ovary, left oophorectomy and total gastrectomy were performed. Pathological examination revealed that the ovarian tumor was a gastric cancer metastasis. Adjuvant chemotherapy with S-1 monotherapy was introduced. Four months after the operation, metastasis was suspected due to right ovary tumor edema. Due to the possibility of obtaining R0 resection and adverse events of chemotherapy, we chose right oophorectomy. Pathological examination demonstrated signet-ring cell cancer. Fourteen months after the first operation, the patient is alive with no recurrence or metastasis.

[A Case of Multiple Gastric GIST with Lymph Nodes Metastases in a Young Woman].

A 21-year-old woman with bloody stool was referred to our hospital with multiple submucosal tumors at the posterior and anterior wall of the gastric angle under upper gastrointestinal endoscopy. Both of the tumors were diagnosed with gastric gastrointestinal stromal tumor(GIST)by EUS-FNA, then laparoscopic distal gastrectomy with D1 lymph node dissection was performed. The size of those tumors were 47 mm and 15 mm respectively, and pathological examination revealed multiple lymph nodes metastases. Neither KIT nor PDGFRA mutation was found. She had received postoperative adjuvant chemotherapy with imatinib mesylate for 3 years. No sign of recurrence has been confirmed thereafter. GISTs in young adults are rare and their oncological features are considered to be different from common type of GIST.

Alternative microexon splicing by RBFOX2 and PTBP1 is associated with metastasis in colorectal cancer.

The splicing of microexons (very small exons) is frequently dysregulated in the brain of individuals with autism spectrum disorder. However, little is known of the patterns, regulatory mechanisms and roles of microexon splicing in cancer. We here examined the transcriptome-wide profile of microexon splicing in matched colorectal cancer (CRC) and normal tissue specimens. Out of 1492 microexons comprising 3 to 15 nucleotides, 21 (1%) manifested differential splicing between CRC and normal tissue. The 21 genes harboring the differentially spliced microexons were enriched in gene ontology terms related to cell adhesion and migration. RNA interference-mediated knockdown experiments identified two splicing factors, RBFOX2 and PTBP1, as regulators of microexon splicing in CRC cells. RBFOX2 and PTBP1 were found to directly bind to microexon-containing pre-mRNAs and to control their splicing in such cells. Differential microexon splicing was shown to be due, at least in part, to altered expression of RBFOX2 and PTBP1 in CRC tissue compared to matched normal tissue. Finally, we found that changes in the pattern of microexon splicing were associated with CRC metastasis. Our data thus suggest that altered expression of RBFOX2 and PTBP1 might influence CRC metastasis through the regulation of microexon splicing.

Wnt5a in cancer-associated fibroblasts promotes colorectal cancer progression.

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment and have been shown to promote cancer aggressiveness. In our previous study, analysis of expression profiles obtained from paired CAFs and normal fibroblasts from colorectal cancer (CRC) tissue revealed that gene sets related to the Wnt signaling pathway were highly enriched in colorectal CAFs. Furthermore, among the components of the ß-catenin-independent Wnt pathway, Wnt5a was highly expressed in CAFs. Since Wnt5a is considered to be a regulator of CRC progression in CAFs, we performed immunohistochemical analysis on Wnt5a in 171 patients who underwent surgery for CRC. Positive staining for Wnt5a was often found in cancer stroma, particularly in fibromatous areas, although the immunoreactivity for Wnt5a was weak in cancer cells. Wnt5a status in CAFs was significantly associated with tumor size, depth of invasion, lymphatic and vascular invasion, lymph node metastasis, TNM stage, and recurrence. Subsequent in vitro analyses using human recombinant Wnt5a protein revealed that cancer cell proliferation and migration were significantly increased by stimulation with Wnt5a. Our findings suggest that Wnt5a-derived CAFs play a crucial role in CRC progression and have potential as a target of anti-cancer therapies.

The association between ERK inhibitor sensitivity and molecular characteristics in colorectal cancer.

The mitogen-activated protein kinase (MAPK) pathway plays an important role in the colorectal cancer (CRC) progression, being supposed to be activated by the gene mutations, such as BRAF or KRAS. Although the inhibitors of extracellular signal-regulated kinase (ERK) have demonstrated efficacy in the cells with the BRAF or KRAS mutations, a clinical response is not always associated with the molecular signature. The patient-derived organoids (PDO) have emerged as a powerful in vitro model system to study cancer, and it has been widely applied for the drug screening. The present study aims to analyze the association between the molecular characteristics which analyzed by next-generation sequencing (NGS) and sensitivity to the ERK inhibitor (i.e., SCH772984) in PDO derived from CRC specimens. A drug sensitivity test for the SCH772984 was conducted using 14 CRC cell lines, and the results demonstrated that the sensitivity was in agreement with the BRAF mutation, but was not completely consistent with the KRAS status. In the drug sensitivity test for PDO, 6 out of 7 cases with either BRAF or KRAS mutations showed sensitivity to the SCH772984, while 5 out of 6 cases of both BRAF and KRAS wild-types were resistant. The results of this study suggested that the molecular status of the clinical specimens are likely to represent the sensitivity in the PDOs but is not necessarily absolutely overlapping. PDO might be able to complement the limitations of the gene panel and have the potential to provide a novel precision medicine.

Evaluation of a 55-gene classifier as a prognostic biomarker for adjuvant chemotherapy in stage III colon cancer patients.

BACKGROUND: Adjuvant chemotherapy reduces the risk of recurrence of stage III colon cancer (CC). However, more effective prognostic and predictive biomarkers are needed for better treatment stratification of affected patients. Here, we constructed a 55-gene classifier (55GC) and investigated its utility for classifying patients with stage III CC. METHODS: We retrospectively identified patients aged 20-79 years, with stage III CC, who received adjuvant chemotherapy with or without oxaliplatin, between the years 2009 and 2012. RESULTS: Among 938 eligible patients, 203 and 201 patients who received adjuvant chemotherapy with and without oxaliplatin, respectively, were selected by propensity score matching. Of these, 95 patients from each group were analyzed, and their 5-year relapse-free survival (RFS) rates with and without oxaliplatin were 73.7 and 77.1%, respectively. The hazard ratios for 5-year RFS following adjuvant chemotherapy (fluoropyrimidine), with and without oxaliplatin, were 1.241 (95% CI, 0.465-3.308; P = 0.67) and 0.791 (95% CI, 0.329-1.901; P = 0.60), respectively. Stratification using the 55GC revealed that 52 (27.3%), 78 (41.1%), and 60 (31.6%) patients had microsatellite instability (MSI)-like, chromosomal instability (CIN)-like, and stromal subtypes, respectively. The 5-year RFS rates were 84.3 and 72.0% in patients treated with and without oxaliplatin, respectively, for the MSI-like subtype (HR, 0.495; 95% CI, 0.145-1.692; P = 0.25). No differences in RFS rates were noted in the CIN-like or stromal subtypes. Stratification by cancer sidedness for each subtype showed improved RFS only in patients with left-sided primary cancer treated with oxaliplatin for the MSI-like subtype (P = 0.007). The 5-year RFS rates of the MSI-like subtype in left-sided cancer patients were 100 and 53.9% with and without oxaliplatin, respectively. CONCLUSIONS: Subclassification using 55GC and tumor sidedness revealed increased RFS in patients within the MSI-like subtype with stage III left-sided CC treated with fluoropyrimidine and oxaliplatin compared to those treated without oxaliplatin. However, the predictive power of 55GC subtyping alone did not reach statistical significance in this cohort, warranting larger prospective studies. TRIAL REGISTRATION: The study protocol was registered in the University Hospital Medical Education Network (UMIN) clinical trial registry (UMIN study ID: 000023879 ).