Serum microRNA Levels as a Biomarker for Diagnosing Non-Alcoholic Fatty Liver Disease in Chinese Colorectal Polyp Patients.

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases and its prevalence is increasing worldwide. It is reported that NAFLD is associated with colorectal polyps. Since identifying NAFLD in its early stages could prevent possible disease progression to cirrhosis and decrease the risk of HCC by early intervention, patients with colorectal polyp may thus be considered a target group for screening NAFLD. This study aimed to investigate the potential of serum microRNAs (miRNAs) in identifying NAFLD for colorectal polyp patients. Serum samples were collected from 141 colorectal polyp patients, of which 38 had NAFLD. The serum level of eight miRNAs was determined by quantitative PCR and delta Ct values of different miRNA pairs which were compared between NAFLD and control groups. A miRNA panel was formulated from candidate miRNA pairs by multiple linear regression model and ROC analysis was performed to evaluate its diagnostic potential for NAFLD. Compared to the control group, the NAFLD group showed significantly lower delta Ct values of miR-18a/miR-16 (6.141 vs. 7.374, p = 0.009), miR-25-3p/miR-16 (2.311 vs. 2.978, p = 0.003), miR-18a/miR-21-5p (4.367 vs. 5.081, p = 0.021) and miR-18a/miR-92a-3p (8.807 vs. 9.582, p = 0.020). A serum miRNA panel composed of these four miRNA pairs significantly identified NAFLD in colorectal polyp patients with an AUC value of 0.6584 (p = 0.004). The performance of the miRNA panel was further improved to an AUC value of 0.8337 (p < 0.0001) when polyp patients with other concurrent metabolic disorders were removed from the analysis. The serum miRNA panel is a potential diagnostic biomarker for screening NAFLD in colorectal polyp patients. This serum miRNA test could be performed for colorectal polyp patients for early diagnosis and for prevention of the disease from progressing into more advanced stages.

MiR-509-3p is oncogenic, targets the tumor suppressor PHLPP2, and functions as a novel tumor adjacent normal tissue based prognostic biomarker in colorectal cancer.

BACKGROUND: Recently the role of microRNAs has been explored immensely as novel regulators and potential biomarkers in several cancers. MiR-509-3p is one such miRNA that has been observed to show a mixed expression in different cancers, while it's expression and clinical relevance in colorectal cancer (CRC) has not yet been characterized. METHODS: We used quantitative PCR to evaluate the expression of miR-509-3p in fresh-frozen CRC tumor tissues and the corresponding tumor-adjacent normal (NAT) tissues from 103 patients. Subsequently, functional studies were performed to further interpret the role of the miRNA in CRC. RESULTS: MiR-509-3p was found to be overexpressed in CRC tissues in nearly 80% of cases and was associated with an aggressive disease presentation. Notably, a higher expression of the miRNA promoted cell proliferation, migration, and invasion of CRC cells in in vitro and in vivo models. Mechanistically, we confirmed that miR-509-3p directly binds the 3'UTR of the tumor suppressor PHLPP2 and inhibits its expression. Furthermore, within the previous 103 clinical tissue specimens, we observed an overexpression of miR-509-3p within the NAT tissue of patients associated with a poor disease prognosis. Using multivariate analysis, it was observed that the expression of miR-509-3p within the NAT tissue was an independent predictor of prognosis in CRC. At the cellular level, through indirect coculture experiments, miR-509-3p was observed to regulate the proliferative, migratory, and invasive behavior of normal colon cells. CONCLUSION: MiR-509-3p strongly contributes to the development and progression of CRC and can potentially function as a prognostic biomarker in the disease.

CD26 Induces Colorectal Cancer Angiogenesis and Metastasis through CAV1/MMP1 Signaling.

CD26 has been reported as a marker for colorectal cancer stem cells endowed with tumor-initiating properties and capable of colorectal cancer (CRC) metastasis. In this study, we investigated the functional effect of CD26 on CRC angiogenesis and metastasis, and the potential underlying mechanism. The functional effects of CD26 overexpression or repression were determined by a wound healing experiment, and cell migration and invasion assays in vitro and in mouse models. Differentially expressed genes regulated by CD26 were identified by genome-wide mRNA expression array and validated by quantitative PCR. CD26 functionally regulated CRC cell migration and invasion in vitro and angiogenesis and metastasis in vivo. Genome-wide mRNA expression array and qPCR showed that MMP1 was up-regulated in CD26+ subpopulation, and a subsequent experiment demonstrated the regulatory effect of CD26 on MMP1 in CRC cell lines with CD26 repression or overexpression. Furthermore, overexpression of CAV1 abrogated the CD26-regulated MMP1 induction in CRC cell lines. This study demonstrated the functional roles of CD26 in inducing CRC migration, invasion, angiogenesis and metastasis and identified the potential involvement of MMP1 and CAV1 in such process. CD26 is an attractive therapeutic target for combating tumor progression to improve the prognosis of CRC patients.

Organoid cultures of early-onset colorectal cancers reveal distinct and rare genetic profiles.

OBJECTIVE: Sporadic early-onset colorectal cancer (EOCRC) has bad prognosis, yet is poorly represented by cell line models. We examine the key mutational and transcriptomic alterations in an organoid biobank enriched in EOCRCs. DESIGN: We established paired cancer (n=32) and normal organoids (n=18) from 20 patients enriched in microsatellite-stable EOCRC. Exome and transcriptome analysis was performed. RESULTS: We observed a striking diversity of molecular phenotypes, including PTPRK-RSPO3 fusions. Transcriptionally, RSPO fusion organoids resembled normal colon organoids and were distinct from APC mutant organoids, with high BMP2 and low PTK7 expression. Single cell transcriptome analysis confirmed the similarity between RSPO fusion organoids and normal organoids, with a propensity for maturation on Wnt withdrawal, whereas the APC mutant organoids were locked in progenitor stages. CRISPR/Cas9 engineered mutation of APC in normal human colon organoids led to upregulation of PTK7 protein and suppression of BMP2, but less so with an engineered RNF43 mutation. The frequent co-occurrence of RSPO fusions with SMAD4 or BMPR1A mutation was confirmed in TCGA database searches. RNF43 mutation was found in organoid from a leukaemia survivor with a novel mutational signature; and organoids with POLE proofreading mutation displayed ultramutation. The cancer organoid genomes were stable over long culture periods, while normal human colon organoids tended to be subject to clonal dominance over time. CONCLUSIONS: These organoid models enriched in EOCRCs with linked genomic data fill a gap in existing CRC models and reveal distinct genetic profiles and novel pathway cooperativity.

Predicting the level of difficulty of the double-stapling technique in laparoscopic total mesorectal excision.

BACKGROUND: The transection of rectum and fashioning of anastomosis is a crucial step in laparoscopic total mesorectal excision (TME) and the double-stapling technique (DST) is often employed. This study aimed to evaluate the factors that were associated with difficult DST. METHOD: Cases of laparoscopic TME were retrospectively reviewed. The clinico-anatomical parameters were retrieved from a prospectively maintained database. In addition, pelvic dimensions were taken by reviewing the magnetic resonance imaging scan. The number of stapler cartridges used for intracorporeal transection of rectum was used as a surrogate for the level of difficulty of DST and its relationship with various parameters were evaluated. RESULTS: There were a total of 121 consecutive cases analyzed. The mean number of stapler cartridges used was 2.1 ± 0.7. Pelvic inlet (p = 0.002) and tumor height (p = 0.015) were predictors of the number of cartridges used, R2 = 0.366. A model was developed to predict the likelihood of transecting the rectum with two or less stapler cartridges, which included the following parameters: gender, pelvic inlet, interspinous distance, intertuberous distance, and tumor height. The predicted probability also correlated with overall operation time (p = 0.009) and anastomotic leakage (p = 0.023). CONCLUSION: The difficulty of DST was associated with patient's clinico-anatomical factors. Surgeons can consider other feasible alternatives, like transanal anastomosis, when a technically challenging DST is anticipated.

How does lymph node yield affect survival outcomes of stage I and II colon cancer?

BACKGROUND: According to the American Joint Committee on Cancer staging for cancer of the colon, a minimum of 12 lymph nodes (LN) has to be sampled for accurate staging. This has bearing on the long-term prognosis and the need for adjuvant chemotherapy. The aim of this study was to revisit the association of lymph node yield and the long-term survival in patients with stages I and II, i.e. node-negative, colon cancer. METHOD: Consecutive patients who underwent elective or emergency curative resections for cancer of colon between the years 2003 and 2012 were retrospectively reviewed. Only patients with stage I or II diseases (AJCC 8th edition) were included. They were analysed in three groups, LN<12, LN12-19 and LN≥20. Their clinic-pathological characteristics were compared. The disease-free (DFS) and overall survival (OS) were estimated with the Kaplan-Meier method and compared with the log-rank test. RESULTS: There was a total of 659 patients included in the analysis. Twelve or more LN were found in 65.6% of the specimens. The mean follow-up was 83.9 months. LN≥20 had significantly better DFS (p = 0.015) and OS (p = 0.036), whereas LN<12 had similar DFS and OS when compared to LN12-19. The advantage in DFS and OS were mainly seen in those with stage II diseases. A lymph node yield of greater than 20 was one of the predictors of favourable DFS, hazard ratio 0.358; 95% CI 0.170-.756, p = 0.007. CONCLUSION: The lymph node yield had a significant association with survival outcomes. A lymph node yield of 20 or more was associated with better survival outcomes. On the other hand, lymph node yield less than 12 was not shown to have inferior survival outcomes when compared to those between 12 and 19.

Colonic perfusion assessment with indocyanine-green fluorescence imaging in anterior resections: a propensity score-matched analysis.

BACKGROUND: Colonic perfusion is crucial for anastomotic healing and this could be evaluated intraoperatively using indocyanine-green fluorescence imaging (ICG FI). The aim of this study was to ascertain whether the use of ICG FI resulted in the reduction of anastomotic complications, i.e. AL and anastomotic stricture. METHODS: Consecutive patients who underwent anterior resections or low anterior resections at our institution in the period from January 1st 2013 to December 31st 2018 were retrospectively reviewed. Surgery performed during the period from January 1st 2013 to December 31st 2015 did not involve the use of ICG FI (ICG-) while surgery during the period from January 1st 2016 to December 31st 2018 was performed with the use of ICG FI (ICG+). The anastomotic leakage rates of the two groups were compared after propensity score matching, taking into account the height of the anastomosis and any history of pelvic irradiation. RESULTS: There was a total of 258 and 317 patients who had surgery with and without ICG FI, respectively. There were 253 patients in each group after propensity score matching. The overall anastomotic leakage rate was 3.6% and 7.9% for ICG+ and ICG-, respectively, (p = 0.035). Subgroup analysis showed that the use of ICG FI was significantly associated with a lower anastomotic leakage rate in total mesorectal excision (TME), 4.7% versus 11.6%, p = 0.043, but not in non-TME resections, 3.5% versus 2.4%, (p = 0.612). ICG FI, together with sex and anastomotic height, were independent predictors of anastomotic leakage. CONCLUSIONS: The routine use of ICG FI was associated with a lower anastomotic leakage rate in anterior resections. The reduction in anastomotic leakage rate was mainly seen in TME.

Overexpression of Pin1 and rho signaling partners correlates with metastatic behavior and poor recurrence-free survival of hepatocellular carcinoma patients.

BACKGROUND: Identification of molecular markers for early detection or prediction of metastasis is crucial for both management of HCC patient postoperative treatment and identify new therapeutic targets to inhibit HCC progression and metastasis. In the current study, we investigated the clinical correlation between Pin1, RhoA and RhoC and their association with HCC metastasis. METHODS: Using a randomized study design of primary HCC samples from 139 patients, we determined messenger RNA expression of Pin1, RhoA and RhoC and their prognostic value. RESULTS: Our findings demonstrated for the first time the clinical correlation of Pin1 in HCC metastasis. Pin1, RhoA and RhoC transcript levels were significantly higher in HCC specimens when compared with the paired adjacent non-tumorous liver. Pin1 overexpression was closely correlated with that of RhoA (R = 0.562, p < 0.001) and RhoC (R = 0.529, p < 0.001), and their co-overexpressions correlated with metastatic HCC (p = 0.000012) and poor recurrence-free survival of HCC patients (p < 0.00001), which showed better prognostic significance than either Pin1, RhoA or RhoC overexpression alone. Co-overexpressions of Pin1 + RhoA/RhoC were also an independent factor for predicting development of metastasis after curative resection in our multivariate regression model (p < 0.001). CONCLUSION: Pin1, RhoA and RhoC co-overexpressions are prognostic factor for metastatic HCC and predict poor recurrence-free survival.

Comparison of early experience of robotic and transanal total mesorectal excision using propensity score matching.

BACKGROUND: Robotic surgery and transanal minimally invasive surgery are the two recently developed techniques, which can overcome the difficult pelvic dissection in conventional laparoscopy. This study aimed to compare the early cases of robotic and transanal total mesorectal excision (taTME) using propensity score matching. METHODS: The first 40 cases of taTME and the first 80 sphincter-saving robotic total mesorectal resection for rectal cancer were selected from the prospectively collected database. Using propensity score matching, the outcomes of 40 matched cases of robotic TME were compared with the 40 cases of taTME. RESULTS: Before matching, patients in the taTME group were significantly younger. The tumors were smaller but more distally located. Significantly more patients in the taTME group received preoperative chemoradiation. After matching, the two groups did not show any differences in gender, age, comorbidity, the level of tumors, and incidences of preoperative chemoradiation. The operating time was significantly shorter (254 vs. 170 min, p < 0.05) and the blood loss was less (50 vs. 150 ml, p = 0.002) in the taTME group. Conversion rate was 5% in both groups. There was no difference in the hospital stay, overall morbidity, the anastomotic leakage rate, and the urinary complication rate between the two groups. More patients in the taTME group did not require a separate abdominal incision. The distal margin, the number of lymph nodes examined, and the rate positive circumferential margin (0 vs. 5%, p = 0.494) were also similar between the two groups. CONCLUSIONS: Both taTME and robotic surgery can achieve favorable outcomes in the rectal cancer resection. Comparison of the early experience of the two procedures with propensity score matching showed the taTME was associated with a shorter operating time, less blood loss, and a higher rate of transanal extraction of the specimen. Further evaluation by randomized trials is warranted.

Is bridge to surgery stenting a safe alternative to emergency surgery in malignant colonic obstruction: a meta-analysis of randomized control trials.

BACKGROUND: Despite studies showing superior results in terms of reduced stoma rate and higher primary anastomosis rate, the safety of bridge to surgery stenting (BTS stent) for left-sided malignant colonic obstruction, especially in oncological terms, remains a concern. AIM: The aim of this meta-analysis was to evaluate whether BTS stent is a safe alternative to emergency surgery (EmS). METHODS: Randomized control trials (RCTs) comparing BTS stent and EmS for left-sided colonic obstruction caused by primary cancer of the colon, up to Sep 2018, were retrieved from the Pubmed, Embase database, clinical trials registry of U. S. National Library of Medicine and BMJ and Google Search. RESULTS: There were seven eligible RCTs, involving a total of 448 patients. Compared to EmS, BTS stent had a significantly lower risk of overall complications (RR = 0.605; 95% CI 0.382-0.958; p = 0.032). However, the overall recurrence rate was higher in the BTS stent group (37.0% vs. 25.9%; RR = 1.425; 95% CI 1.002-2.028; p = 0.049). BTS stent significantly increased the risk of systemic recurrence (RR = 1.627; 95% CI 1.009-2.621; p = 0.046). This did not translate into a significant difference in terms of 3-year disease-free survival or 3-year overall survival. CONCLUSION: BTS stent is associated with a lower rate of overall morbidities than EmS. However, BTS stent was associated with a greater chance of recurrence, especially systemic recurrence. Clinicians ought to be aware of the pros and cons of different interventions and tailor treatments for patients suffering from left-sided obstructing cancer of the colon.

Dietary changes adopted by Chinese colorectal cancer patients: A qualitative study.

OBJECTIVE: To explore influences on post-diagnosis dietary decision-making in colorectal cancer survivors (CRC) for future intervention development. METHODS: Individual semi-structured interviews were conducted with 30 CRC survivors. All interviews were recorded and transcribed verbatim for grounded theory analysis. RESULTS: Most CRC survivors interviewed reported making both short- and long-term changes post-diagnosis, influenced by physical symptoms and personal beliefs: short-term treatment-driven changes to facilitate recovery, manage treatment side-effects and avoid disruption in treatment; short-term 'patient role' driven changes heavily influenced by family members and cultural beliefs; long-term changes driven by residual symptoms and illness beliefs, including cancer causal attributions and beliefs about preventing future recurrences. Traditional Chinese medicinal (TCM) beliefs were influential in both short- and long-term dietary decision-making, which may explain why survivors focused on specific food items rather than food patterns. CONCLUSION: While our findings suggested that the majority of CRC survivors made dietary changes post-diagnosis, their dietary pattern and motivation may change over the course of their illness trajectory. Also, the types of changes made are often not consistent with existing dietary recommendations. It is necessary to consider illness perception and cultural beliefs when delivering dietary care or developing interventions for this population.

Outcomes of colorectal cancer surgery in the nonagenarians: 20-year result from a tertiary center.

BACKGROUND: There is a foreseeable trend that life expectancy is on the rise in many parts of the world. More and more patients will present with colorectal cancer at extreme old age and advanced age is a well-known risk factor for adverse outcomes after surgery. The aim of this study is to evaluate the outcomes of colorectal cancer surgery in patients aged 90 or above. METHOD: A retrospective analysis of consecutive patients aged 90 or above who underwent operations for colorectal cancer between January 1996 and December 2015 was performed. The primary outcomes were the complications rate, 30-day and 180-day mortality rates. RESULTS: A total of 57 patients were included in the analysis. The majority of them were women (64.9%). The median age was 92 years. Most of the surgery was of curative intent (77.2%), performed under elective setting (57.9%) and with open approach (78.9%). 36.8% of patients had postoperative complications, with pneumonia being the commonest. The 30-day and 180-day mortality rate was 7 and 31.6% respectively. History of ischemic heart disease and surgery under emergency setting were predictors of postoperative complications. Pneumonia, preoperative leukocytosis and Charlson comorbidity score ≥ 9 were predictors of 180-day mortality. The one and two-year survival rate for elective surgery was 69.7 and 54.5% respectively. CONCLUSION: The outcomes of colorectal cancer surgery for nonagenarians could be favorable in a selected group of patients. Future study on better risk profiling and ways to improve outcomes is warranted.

The impact of indocyanine-green fluorescence angiogram on colorectal resection.

BACKGROUND: Perfusion plays an important role in anastomotic healing. Indocyanine-green fluorescence angiogram allows objective bowel perfusion assessment. This study aimed to investigate the impact of perfusion assessment on intraoperative decision during left-sided colorectal resections. METHOD: This was a prospective, single-centre, observational study recruiting patients with left-sided colorectal resections. Perfusion of bowel segment was assessed with ICG fluorescence angiogram prior to resection and anastomosis intra-operatively. The planned transection site and the actual transection site after perfusion assessment were compared. The decision for diversion stoma was also evaluated. RESULTS: 110 patients with cancer of the sigmoid colon (29.1%) and rectum (70.9%) were recruited. Total mesorectal excision was performed in 51.8% of patients. The transection site was revised in 34.5% of cases: 30.9% more proximally and 3.6% more distally. The median distance between the intended and actual transection sites was 2 cm (range 1-17 cm). A proximal revision in the transection site was more likely seen in rectal cancers (p = 0.036, OR 3.58, 95% CI 1.09-11.78) and relatively under-perfused left colon (p = 0.036, OR 1.01, 95% CI 1.01-1.02). Three (2.7%) patients were spared from a diversion stoma. The overall anastomotic leakage rate was 5.5%. CONCLUSION: ICG fluorescence angiogram altered operative decisions in a significant proportion of cases. The impact on transection site was more pronounced in patients with rectal cancers and those with relatively under-perfused colon.

Robotic-Assisted Transrectal Cholecystectomy in a Porcine Model.

Background. With increasing experience and technological advancement in surgical instruments, surgeons have explored the feasibility of single-incision laparoscopic surgery and natural orifice transluminal endoscopic surgery (NOTES). These techniques aim to further reduce surgical trauma, but are not popular due to their inherent pitfalls including clashing of instruments, lack of counter traction, lengthy operating time, and so on. A novel surgical robotic system was designed to overcome the limitations of the existing technologies. Animal trials were conducted to demonstrate its feasibility in performing robotic-assisted transrectal cholecystectomy in a porcine model. Method. The Novel surgical robotic system is a high dexterity, single access port surgical robotic system that enables surgeons to carry out single-port surgical procedure or NOTES. The proposed system's main features include the ability to perform intraabdominal and pelvic surgeries via natural orifices like the vagina or rectum. The system is equipped with multiple miniaturized (16 mm diameter) internally motorized robotic arms, each with a minimum of 7 degrees of freedom, a dual in vivo camera system, a cannula, and an external swivel system. Results. Robotic-assisted transrectal cholecystectomy was successfully performed in 3 adult male pigs. The estimated blood loss was <10 mL in all 3 cases. There were no intraoperative complications. The system provided good dexterity and clear vision. Conclusions. The trial demonstrated that the system can provide the surgeon a stable platform with adequate spacing for the transrectal insertion of robotic arms, 3-dimensional vision, and enhanced dexterity in performing NOTES cholecystectomy.

Suppression of Slit3 induces tumor proliferation and chemoresistance in hepatocellular carcinoma through activation of GSK3ß/ß-catenin pathway.

BACKGROUND: It is essential to understand the mechanisms responsible for hepatocellular carcinoma (HCC) progression and chemoresistance in order to identify prognostic biomarkers as well as potential therapeutic avenues. Recent findings have shown that SLIT3 appears to function as a novel tumor suppressor gene in various types of cancers, yet its clinical correlation and role in HCC has not been understood clearly. METHODS: We determined the transcript levels of Slit3 in tumor and adjacent normal tissues within two cohorts (N = 40 and 25) of HCC patients, and correlated the gene expression with the clinicopathological data. Subsequently, the functional effects and underlying molecular mechanisms of Slit3 overexpression and/or repression were studied using cell-line and mouse models. RESULTS: Our results demonstrated a repression in Slit3 expression in nearly 50% of the HCC patients, while the overall expression of Slit3 inversely correlated with the size of the tumor in both cohorts of patients. Stable down-regulation of Slit3 in HCC cell-lines induced cell proliferation in vitro and tumor growth in vivo, while stable Slit3 overexpression repressed these effects. Molecular investigations showed that the stable Slit3 repression-induced cell proliferation was associated with a higher expression of ß-catenin and a repressed GSK3ß activity. Moreover, Slit3-repression induced chemoresistance to sorafenib, oxaliplatin and 5-FU through impairment of ß-catenin degradation and induction of cyclin D3 and survivin levels. The effects induced by stable Slit3-repression were diminished by transient repression of ß-catenin by siRNA approach. CONCLUSION: This study suggests that Slit3 acts as a tumor suppressor in HCC by repressing the tumor growth and thus tumor progression. Low Slit3 level indicates a poor response of HCC cells to chemotherapy. Restoration or overexpression of Slit3 is a potential therapeutic approach to repress the tumor growth and enhance the efficacy of chemotherapeutic agents.

Does advancement in stapling technology with triple-row and enhanced staple configurations confer additional safety? A matched comparison of 340 stapled ileocolic anastomoses.

BACKGROUND: Over the past few decades, studies have focused on the safety of stapled anastomosis, especially when compared to that of the handsewn technique. However, studies on the improvement of stapling technology are limited. This study aimed to investigate whether linear triple-row staples (tri-staples) had any advantage over double-row staples. METHODS: This is a retrospective review of all cases of functional end-to-end anastomoses with linear staplers performed at two centers between 2005 and 2015. Data were retrieved from a prospectively maintained database. Cases of anastomoses performed with double-row (DS) and triple-row (TS) staples were matched according to propensity scores. The rates of anastomotic leakage, bleeding, reoperation, and 30-day mortality were compared. RESULTS: Functional end-to-end ileocolic anastomoses were performed in 563 consecutive patients during the study period. Double- and triple-row stapling devices were used in 389 and 174 anastomoses, respectively. With propensity score matching, 170 cases were chosen from each group. Both groups showed comparable baseline characteristics. The anastomotic leakage, anastomotic bleeding, and intra-abdominal collection rates were 2.4 and 0% (p = 0.123), 1.2 and 0% (p = 0.499), and 3.5 and 1.2% (p = 0.283) for DS and TS, respectively. The reoperation and 30-day mortality rates were 5.9 and 1.8% (p = 0.048) and 0.6 and 1.2% (p = 1.000) for DS and TS, respectively. The median lengths of stay were 5 and 6 days (p = 0.072) for DS and TS, respectively. CONCLUSION: Anastomoses with triple-row staples tended to have a lower morbidity rate, but a significant advantage over double-row staples was not demonstrated in this study.

RNF43 germline and somatic mutation in serrated neoplasia pathway and its association with BRAF mutation.

OBJECTIVE: Serrated polyps (hyperplastic polyps, sessile or traditional serrated adenomas), which can arise in a sporadic or polyposis setting, predispose to colorectal cancer (CRC), especially those with microsatellite instability (MSI) due to MLH1 promoter methylation (MLH1me+). We investigate genetic alterations in the serrated polyposis pathway. DESIGN: We used a combination of exome sequencing and target gene Sanger sequencing to study serrated polyposis families, sporadic serrated polyps and CRCs, with validation by analysis of The Cancer Genome Atlas (TCGA) cohort, followed by organoid-based functional studies. RESULTS: In one out of four serrated polyposis families, we identified a germline RNF43 mutation that displayed autosomal dominant cosegregation with the serrated polyposis phenotype, along with second-hit inactivation through loss of heterozygosity or somatic mutations in all serrated polyps (16), adenomas (5) and cancer (1) examined, as well as coincidental BRAF mutation in 62.5% of the serrated polyps. Concurrently, somatic RNF43 mutations were identified in 34% of sporadic sessile/traditional serrated adenomas, but 0% of hyperplastic polyps (p=0.013). Lastly, in MSI CRCs, we found significantly more frequent RNF43 mutations in the MLH1me+ (85%) versus MLH1me- (33.3%) group (p<0.001). These findings were validated in the TCGA MSI CRCs (p=0.005), which further delineated a significant differential involvement of three Wnt pathway genes between these two groups (RNF43 in MLH1me+; APC and CTNNB1 in MLH1me-); and identified significant co-occurrence of BRAF and RNF43 mutations in the MSI (p<0.001), microsatellite stable (MSS) (p=0.002) and MLH1me+ MSI CRCs (p=0.042). Functionally, organoid culture of serrated adenoma or mouse colon with CRISPR-induced RNF43 mutations had reduced dependency on R-spondin1. CONCLUSIONS: These results illustrate the importance of RNF43, along with BRAF mutation in the serrated neoplasia pathway (both the sporadic and familial forms), inform genetic diagnosis protocol and raise therapeutic opportunities through Wnt inhibition in different stages of evolution of serrated polyps.

Comparison of short-term and oncologic outcomes of robotic and laparoscopic resection for mid- and distal rectal cancer.

PURPOSE: Laparoscopic rectal resection with total mesorectal excision is a technically challenging procedure, and there are limitations in conventional laparoscopy. A surgical robotic system may help to overcome some of the limitations. This study aimed to compare the short-term operative as well as oncologic outcomes of laparoscopic and robotic rectal resection. METHODS: This study was based on a prospectively collected database of patients with mid- to distal rectal cancer (up to 12 cm from the anal verge) undergoing either laparoscopic or robotic low anterior resection from January 2008 to June 2015. Data on patient demographics, intraoperative parameters and short-term outcomes were analyzed. Patient survival and recurrence were also compared. RESULTS: During the study period, 171 and 220 consecutive patients underwent laparoscopic and robotic rectal resection, respectively. The median age was 65 years (range 23-96). The median tumor distance was 8 and 7 cm from the anal verge in the laparoscopic and robotic groups, respectively (p = 0.06). Significantly more male patients and more patients with comorbidities and preoperative radiation underwent robotic surgery. The median operating time for robotic resection was significantly longer, 260 versus 225 min (p < 0.001). Conversion rates of laparoscopic and robotic resection were 3.5 and 0.8 %, respectively (p = 0.308). The median hospital stay was 6 days in both groups (p = 0.29). There was no difference in the overall complication rate, but the incidence of urinary retention was significantly less in the robotic group (4.1 vs. 10.5 %, p = 0.024). With a median follow-up of 31 months, there was no difference in local recurrence, overall survival and disease-specific survival between the two groups. CONCLUSIONS: In the treatment of mid- to low rectal cancer, robotic resection can achieve operative results and oncologic outcomes comparable to laparoscopic resection. The postoperative urinary retention rate is lower following robotic surgery.

Sphincter-Preserving Surgery for Low Rectal Cancers: Incidence and Risk Factors for Permanent Stoma.

BACKGROUND: Advances in surgical techniques and paradigm changes in rectal cancer treatment have led to a drastic decline in the abdominoperineal resection rate, and sphincter-preserving operation is possible in distal rectal cancer. OBJECTIVE: The aim of this study is to evaluate the long-term incidence of permanent stoma after sphincter-preserving surgery for low rectal cancer and its corresponding risk factors. METHOD: From 2000 to 2014, patients who underwent sphincter-preserving low anterior resection for low rectal cancer (within 5 cm from the anal verge) were included. The occurrence of permanent stoma over time and its risk factors were investigated by using a Cox proportional hazards regression model. RESULTS: This study included 194 patients who underwent ultra-low anterior resection for distal rectal cancer, and the median follow-up period was 77 months for the surviving patients. Forty-six (23.7%) patients required a permanent stoma eventfully. Anastomotic-related complications and disease progression were the main reasons for permanent stoma. Clinical anastomotic leakage (HR 5.72; 95% CI 2.31-14.12; p < 0.001) and neoadjuvant chemoradiation (HR 2.34; 95% CI 1.12-4.90; p = 0.024) were predictors for permanent primary stoma. Local recurrence (HR 16.09; 95% CI 5.88-44.03; p < 0.001) and T4 disease (HR 11.28; 95% CI 2.99-42.49; p < 0.001) were predictors for permanent secondary stoma. The 5- and 10-year cumulative incidence for permanent stoma was 24.1 and 28.0%, respectively. CONCLUSION: Advanced disease, prior chemoradiation, anastomotic leakage and local recurrence predispose patients to permanent stoma should be taken into consideration when contemplating sphincter-preserving surgery.

Emergence of CD26+ Cancer Stem Cells with Metastatic Properties in Colorectal Carcinogenesis.

Colorectal cancer results from genetic aberrations which accumulate over a long period of time, with malignant and metastatic properties acquired at a relatively late stage. A subpopulation of CD26+ colorectal cancer stem cells are known to be implicated in metastasis. We quantified CD26+ cancer cells in 11 primary tumor samples by flow cytometry, and showed that tumors having confirmed or suspected metastases harbored a relatively high CD26+ level in these samples. We hypothesized that this subpopulation of cancer stem cells arises in the late stage of carcinogenesis from the bulk of tumor daughter cells which are CD26-. The manipulation of PIK3CA and TP53, two genes commonly deregulated in the late stage, had an effect on the maintenance of the CD26+ cell population. When CD26- tumor daughter cells were sorted and cultured, the emergence of tumor spheres containing CD26+ cells occurred. These findings shed light to the origin of colorectal cancer stem cells with metastatic properties, which has an implication on conventional treatments by surgery or adjuvant chemotherapy for tumor debulking.