Background: This meta-analysis was aimed to quantitatively assess the associations of metabolic syndrome (MetS) and its components with colorectal cancer (CRC). Methods: PubMed, EMBASE and Web of Science databases were systematically searched for eligible studies. A total of 18 studies for CRC incidence and 12 studies for CRC mortality were identified. Results: MetS was associated with an increased risk of CRC incidence and mortality in male (RR: 1.28, 95 % CI 1.16-1.39, and 1.24, 1.18-1.31, respectively) and correlated with an increased risk of CRC incidence in female (RR: 1.21, 1.13-1.30), but not with CRC mortality in female. MetS increased the risk of cancer-specific mortality (RR: 1.72, 1.03-2.42), but not overall mortality. The risk estimates of CRC incidence changed little depending on age, sex, cancer site, the type of studies, ethnicity, publication year, or definition of MetS. As for CRC mortality, further stratified analyses indicated statistical significance in studies with assessing cancer-specific survival outcome, in male, a cohort design, ethnicity of non-Chinese or with definition of MetS as ≥ 3 metabolic abnormalities. Obesity and hyperglycemia are risk factors of CRC incidence in both male and female. Only dysglycemia is the risk factor for CRC mortality. Conclusions: MetS is associated with an increased risk of CRC incidence and cancer-specific mortality, but not overall mortality. In addition, MetS may increase the CRC mortality in male rather than in female. However, since most of the studies on CRC mortality were conducted in Chinese, further studies are needed to clarify this connection.

Growing evidences demonstrate that long noncoding RNAs (lncRNAs) participate in various cancers including colorectal cancer (CRC). In the current study, we found that the expression of DSCAM-AS1 in CRC tissues and cell lines was significantly upregulated, and was positively correlated with metastasis status and advanced stage of CRC. In addition, Kaplan-Meier assays also indicated that the expression of DSCAM-AS1 was correlated with poor prognosis in patients with CRC. Silence of DSCAM-AS1 inhibited proliferation and migration of CRC cells. Subcellular fractionation and FISH analyses suggested that DSCAM-AS1 was majorly distributed in cytoplasm of HT29 and LOVO cells. Thus, DSCAM-AS1 might act as a competing endogenous RNA (ceRNA). Subsequently, RT-qPCR results displayed that the expression of miR-137 in CRC tissues was relatively lower than that in the neighboring normal tissues. The interaction between miR-137 and DSCAM-AS1 was demonstrated by luciferase reporter assay. Functionally, miR-137 reversed the pro-proliferation and-metastasis effect of DSCAM-AS1 on CRC cells. Collectively, DSCAM-AS1 promotes CRC progression via sponging miR-137. MiR-137 can suppress the expression of Notch-1, a novel signaling regulating cell proliferation and EMT, by working on the 3'UTR of Notch-1. At last, Notch-1 overexpression or miR-137 inhibition could restore the DSCAM-AS1 silencing-mediated repressive function on cell proliferation and migration. The above data suggested that, DSCAM-AS1 may contribute to CRC cell proliferation and migration by targeting miR-137/Notch-1 axis.

Epidemiological studies have suggested inconclusive associations between 25-hydroxyvitamin D (25(OH)D) and survival in patients with colorectal cancer (CRC). The aim of this study was to quantitatively assess these associations. PubMed, EMBASE and Web of Science databases were systematically searched for eligible studies. Subgroup analyses based on study geographic location, publication year, length of follow-up time, sample size, and stage were conducted to explore potential sources of heterogeneity. Dose-response relationships and pooled hazard ratios (HR) for overall and CRC-specific survival comparing the highest versus the lowest categories of circulating 25(OH)D concentrations were assessed. Overall, 17 original studies with a total of 17770 CRC patients were included. Pooled HR (95% confidence intervals) comparing highest versus lowest categories were 0.64 (0.55-0.72) and 0.65 (0.56-0.73) for overall and CRC-specific survival, respectively. Studies conducted in the USA, with median follow-up time ≥ 8 years, larger sample size, and including stage I-III patients showed a more prominent association between 25(OH)D concentrations and overall survival. The dose-response analysis showed that the risk of all-cause mortality was reduced by 7% (HR = 0.93; 95% CI: 0.90, 0.95), and the risk of CRC-specific mortality was reduced by 12% (HR = 0.88; 95% CI: 0.84, 0.93) for each 20 nmol/L increment of 25(OH)D concentration. This meta-analysis provides evidences that a higher 25(OH)D concentration is associated with lower overall mortality and CRC-specific mortality.

Evidence shows that long noncoding RNAs (lncRNAs) play key roles in various cancers, including colorectal cancer. In this current study, we found that the expression of ZEB1-AS1 in colorectal cancer tissues and cell lines was significantly upregulated, and positively correlated with advanced stage of colorectal cancer. Kaplan-Meier assays also indicated that the expression of ZEB1-AS1 was correlated with poor prognosis in patients with colorectal cancer. Knocking down of ZEB1-AS1 inhibited the proliferation of colorectal cancer cells. Subcellular fractionation analyses suggested that ZEB1-AS1 was majorly distributed in cytoplasm of SW480 and LOVO cells. Thus, ZEB1-AS1 might act as a competing endogenous RNA. MicroRNA array analysis suggested that miR-141-3p was significantly downregulated in CRC tissues, which was further verified by RT-qPCR. The results of luciferase reporter assay proved that miR-141-3p was a target of ZEB1-AS1. Functionally, miR-141-3p inhibitor reversed the anti-proliferation effect of sh-ZEB1-AS1 on colorectal cancer cells. Collectively, ZEB1-AS1 may contribute to colorectal cancer cell proliferation by sponging miR-141-3p.

Background: The surgical management of left-sided malignant large bowel obstruction (MLBO) is associated with high morbidity and mortality. Recently, self-expandable metallic colonic stent (SEMS) and transanal decompression tube (TDT) used as a 'bridge to surgery' (BTS) have been widely used. This study aims to compare the clinical outcomes and oncological safety of SEMS and TDT as BTS to transform MLBO into elective surgery. Methods: Between February 2013 and March 2019, 62 patients with MLBO received SEMS (n = 32) or TDT (n = 30), and elective one-stage surgery later. We evaluated decompression efficiency and oncological safety in selective operation in TDT and SEMS groups, including preoperative preparation time, surgical approach, number of lymphatic dissection and vascular invasion, ulcer formation and histopathological findings of resected specimens. Results: The preoperative preparation time in the SEMS group was shorter than that of the TDT group (P < 0.05). However, there was no significant difference between the groups in postoperative length of hospital stay (P > 0.05). The number of vascular invasions in the TDT group was less than that in the SEMS group (P < 0.05). Furthermore, the risk of wound abscess and ulcer formation in the TDT group was significantly lower than that in the SEMS group (P < 0.05). Conclusion: Our findings suggest that SEMS is associated with a relatively poor oncological outcome and the placement of TDT as BTS in MLBO patients may be a better alternation.