The deficiency of 5-methylcytosine (5mC) and its ramification in the occurrence and prognosis of colon cancer

The incidence and mortality of colon cancer are increasing, and effective biomarkers for its diagnosis are limited. 5-methylcytosine (5mC), a vital DNA methylation marker, plays important roles in gene expression, genomic imprinting, and transposon inhibition. This study aimed to identify the predictors of colon cancer prognosis and lay the foundation for research on therapeutic targets by detecting the levels of 5mC, 5-hydroxymethylcytosine (5hmC), 5-formyl cytosine (5fC), and 5-carboxylcytosine (5caC) in colon cancer and adjacent non-tumor tissues. A tissue microarray including 100 colon cancer tissue samples and 60 adjacent non-tumor tissue samples was used. The expression levels of 5mC and its ramifications were assessed by immunohistochemistry. According to the expression levels, patients were divided into moderately positive and strongly positive groups, and the correlation between clinicopathological characteristics and methylation marks was assessed using 2-sided chi-square tests. The prognostic values of 5mC, 5hmC, 5fC, and 5caC were tested using Kaplan-Meier analyses. Compared with adjacent non-tumor tissues, the overall levels of DNA methylation were lower in colon carcinoma lesions. However, the clinical parameters were not significantly associated with these methylation markers, except for 5hmC, which was associated with the age of cancer patients (P value = .043). Kaplan-Meier analysis disclosed that moderate positive group had a significantly shorter disease specific survival than strong positive group for patients with different levels of 5mC (65.2 vs 95.2 months, P = .014) and 5hmC (71.2 vs 97.5 months, P = .045). 5mC and its ramifications (5hmC, 5fC, and 5caC) can serve as biomarkers for colon cancer. 5mC and 5hmC are stable predictors and therapeutic targets in colon cancer. However, further understanding of its function will help to reveal the complex tumorigenic process and identify new therapeutic strategies.

Serum and peritoneal biomarkers for the early prediction of symptomatic anastomotic leakage in patients following laparoscopic low anterior resection: A single-center prospective cohort study

BACKGROUND

Anastomotic leakage (AL) is one of the common complications after rectal cancer surgery. This study aimed to evaluate the combination of biomarkers for the early prediction of symptomatic AL after surgery.

METHODS

A prospective cohort study evaluated the serum and peritoneal biomarkers of patients who underwent laparoscopic low anterior resection (Lap LAR) from November 1, 2021, to May 1, 2022. Multivariate-penalized logistic regression was performed to explore the independent biomarker with a P-value <.1, and receiver operating characteristic (ROC) curve was used to analyze the area under the curve (AUC), sensitivity, and specificity of the independent biomarkers. A predictive model for symptomatic AL was built based on the independent biomarkers and was visualized with a nomogram. The calibration curve with the concordance index (c-index) was further applied to evaluate the efficacy of the predictive model.

RESULTS

A total of 157 patients were included in this study, and 7 (4.5%) were diagnosed with symptomatic AL. C-reactive protein/album ratio (CAR) on postoperative day 1 and systemic immune-inflammation index (SII) and peritoneal interleukin-6 (IL-6) on postoperative day 3 were proven to be independent predictors for the early prediction of symptomatic AL. The optimal cutoff values of CAR, SII, and peritoneal IL-6 were 1.04, 916.99, and 26430.09 pg/ml, respectively. Finally, the nomogram, including these predictors, was established, and the c-index of this nomogram was 0.812, indicating that the nomogram could be used for potential clinical reference.

CONCLUSION

The combination of CAR, SII, and peritoneal IL-6 might contribute to the early prediction of symptomatic AL in patients following Lap LAR. Given the limitations of this study and the emergence of other novel biomarkers, multicenter prospective studies are worthy of further exploration.

Effect of the transanal drainage tube on preventing anastomotic leakage after laparoscopic surgery for rectal cancer: a systematic review and meta-analysis

PURPOSE

Anastomotic leakage (AL) is a common postoperative complication of rectal cancer, and transanal drainage tube (TDT) efficacy is still contentious. This study aimed to evaluate the TDT effect on AL prevention.

METHODS

All relevant papers were searched by using a predefined search strategy (two randomized controlled trials (RCTs), one prospective study, and four retrospective studies). Meta-analysis was conducted to estimate AL and re-operation pooled rates.

RESULTS

A total of 7 studies (1556 patients) were included: No significant statistic difference was found between two groups on AL rate (odds ratio (OR) 0.61, P = 0.11) and re-operation rate (OR 0.52, P = 0.10). For subgroup analysis, significant statistic difference was found between two groups on AL rate (OR 0.29, P = 0.002) and re-operation rate (OR 0.15, P = 0.04) in patients without neoadjuvant therapy. As for patients without diverting stoma, the AL rate (OR 0.35, P = 0.002) was significantly lower than that in patients without TDT.

CONCLUSIONS

TDT may reduce AL morbidity and re-operation rate for patients without high risk of AL, but may be useless for those in high-risk situations.

Peritoneal Cytokines as Early Biomarkers of Colorectal Anastomotic Leakage Following Surgery for Colorectal Cancer: A Meta-Analysis

Background

Postoperative colorectal anastomotic leakage (CAL) is a devastating complication following colorectal resection. However, the diagnosis of anastomotic leakage is often delayed because the current methods of identification are unable to achieve 100% clinical sensitivity and specificity. This meta-analysis aimed to evaluate the predictive value of peritoneal fluid cytokines in the detection of CAL following colorectal surgery.

Methods

A comprehensive search was conducted on PubMed, Embase, Cochrane Library, and Web of Science before June 2021 to retrieve studies regarding peritoneal fluid cytokines as early markers of CAL. Pooled analyses of interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF) were performed. The means (MD) and standard deviations (SD) of the peritoneal fluid cytokines were extracted from the included studies. Review Manager Software 5.3 was used for data analysis.

Results

We included eight studies with 580 patients, among which 85 (14.7%) and 522 (44.5%) were evaluated as the CAL and non-CAL groups, respectively. Compared to the non-CAL group, the CAL group had significantly higher peritoneal IL-6 levels on postoperative day (POD) 1–3 (P = 0.0006, 0.0002, and 0.002, respectively) and slightly higher TNF levels on POD 4 (P = 0.0002). Peritoneal levels of IL-1β and IL-10 were not significantly different between the two groups in this study.

Conclusion

Peritoneal IL-6 levels can be a diagnostic marker for CAL following colorectal surgery, whereas the value of TNF needs further exploration in the future.

Systematic Review Registration

[https://www.crd.york.ac.uk/prospero/#myprospero], PROSPERO (CRD42021274973)

D2 dissection in laparoscopic and open gastrectomy for gastric cancer

AIM: To evaluate the radicalness and safety of laparoscopic D2 dissection for gastric cancer.

METHODS: Clinicopathological data from 209 patients with gastric cancer, who underwent radical gastrectomy with D2 dissection between January 2007 and February 2011, were analyzed retrospectively. Among these patients, 131 patients underwent laparoscopy-assisted gastrectomy (LAG) and 78 underwent open gastrectomy (OG). The parameters analyzed included operative time, blood loss, blood transfusion, morbidity, mortality, the number of harvested lymph nodes (HLNs), and pathological stage.

RESULTS: There were no significant differences in sex, age, types of radical resection [radical proximal gastrectomy (PG + D2), radical distal gastrectomy (DG + D2) and radical total gastrectomy (TG + D2)], and stages between the LAG and OG groups (P > 0.05). Among the two groups, 127 cases (96.9%) and 76 cases (97.4%) had 15 or more HLNs, respectively. The average number of HLNs was 26.1 ± 11.4 in the LAG group and 24.2 ± 9.3 in the OG group (P = 0.233). In the same type of radical resection, there were no significant differences in the number of HLNs between the two groups (PG + D2: 21.7 ± 7.5 vs 22.4 ± 9.3; DG + D2: 25.7 ± 11.0 vs 22.3 ± 7.9; TG + D2: 30.9 ± 13.4 vs 29.3 ± 10.4; P > 0.05 for all comparisons). Tumor free margins were obtained in all cases. Compared with OG group, the LAG group had significantly less blood loss, but a longer operation time (P < 0.001). The morbidity of the LAG group was 9.9%, which was not significantly different from the OG group (7.7%) (P = 0.587). The mortality was zero in both groups.

CONCLUSION: Laparoscopic D2 dissection is equivalent to OG in the number of HLNs, regardless of tumor location. Thus, this procedure can achieve the same radicalness as OG.