Primary Surgery Followed by Selective Chemoradiotherapy Versus Preoperative Chemoradiotherapy Followed by Surgery for Locally Advanced Rectal Cancer: A Randomized Clinical Trial

PURPOSE

The aim of this work was to determine whether locally advanced rectal cancer (LARC) with negative mesorectal fascia (MRF) predicted by magnetic resonance imaging (MRI) can be excluded from preoperative radiation therapy treatment.

METHODS AND MATERIALS

This multicenter, open-label, non-inferiority, randomized clinical trial enrolled patients with LARC within 6 to 12 cm from the anal verge and with negative MRI-predicted MRF. Participants were randomized to the intervention group (primary surgery, in which the patients with positive pathologic [CRM] circumferential margins were subjected to chemoradiotherapy [CRT] and those with negative CRM underwent adjuvant chemotherapy according to pathologic staging) or the control group (preoperative CRT, in which all patients underwent subsequent surgery and adjuvant chemotherapy). The primary endpoint was 3-year disease-free survival (DFS).

RESULTS

A total of 275 patients were randomly assigned to the intervention (n = 140) and control (n = 135) groups, in which 33.57% and 28.15% patients were at clinical T4 stage and 85.92% and 80.45% patients were at "bad" or "ugly" risk in the intervention and control groups, respectively. There were 2 patients (1.52%) and 1 patient (0.77%) with positive CRM in the intervention and control groups, respectively (P > .05). The non-adherence rates for the intervention and control groups were 3.6% and 23.7%, respectively. After a median follow-up of 34.6 months (IQR, 18.2-45.7), 43 patients had positive events (28 patients and 15 patients in the intervention and control groups, respectively). There were 6 patients (4.4%) with local recurrence in the intervention group and none in the control group, which led to the termination of the trial. The 3-year DFS rate was 81.82% in the intervention group (95% CI, 78.18%-85.46%) and 85.37% in the control group (95% CI, 81.75%-88.99%), with a difference of -3.55% (95% CI, -3.71% to -3.39%; hazard ratio, 1.76; 95% CI, 0.94-3.30). In the per-protocol data set, the difference between 3-year DFS rates was -5.44% (95% CI, -5.63% to -5.25%; hazard ratio, 2.02; 95% CI, 1.01-4.06).

CONCLUSIONS

Based on the outcomes of this trial, in patients with LARC and MRI-negative MRF, primary surgery could negatively influence their DFS rates. Therefore, primary surgery was an inferior strategy compared with preoperative CRT followed by surgery and cannot be recommended for patients with LARC.

[Development and validation of a prognostic prediction model for patients with stage Ⅰ to Ⅲ colon cancer incorporating high-risk pathological features]

Objective: To examine a predictive model that incorporating high risk pathological factors for the prognosis of stage Ⅰ to Ⅲ colon cancer. Methods: This study retrospectively collected clinicopathological information and survival outcomes of stage Ⅰ~Ⅲ colon cancer patients who underwent curative surgery in 7 tertiary hospitals in China from January 1, 2016 to December 31, 2017. A total of 1 650 patients were enrolled, aged (M(IQR)) 62 (18) years (range: 14 to 100). There were 963 males and 687 females. The median follow-up period was 51 months. The Cox proportional hazardous regression model was utilized to select high-risk pathological factors, establish the nomogram and scoring system. The Bootstrap resampling method was utilized for internal validation of the model, the concordance index (C-index) was used to assess discrimination and calibration curves were presented to assess model calibration. The Kaplan-Meier method was used to plot survival curves after risk grouping, and Cox regression was used to compare disease-free survival between subgroups. Results: Age (HR=1.020, 95%CI: 1.008 to 1.033, P=0.001), T stage (T3:HR=1.995,95%CI:1.062 to 3.750,P=0.032;T4:HR=4.196, 95%CI: 2.188 to 8.045, P<0.01), N stage (N1: HR=1.834, 95%CI: 1.307 to 2.574, P<0.01; N2: HR=3.970, 95%CI: 2.724 to 5.787, P<0.01) and number of lymph nodes examined (≥36: HR=0.438, 95%CI: 0.242 to 0.790, P=0.006) were independently associated with disease-free survival. The C-index of the scoring model (model 1) based on age, T stage, N stage, and dichotomous variables of the lymph nodes examined (<12 and ≥12) was 0.723, and the C-index of the scoring model (model 2) based on age, T stage, N stage, and multi-categorical variables of the lymph nodes examined (<12, 12 to <24, 24 to <36, and ≥36) was 0.726. A scoring system was established based on age, T stage, N stage, and multi-categorical variables of lymph nodes examined, the 3-year DFS of the low-risk (≤1), middle-risk (2 to 4) and high-risk (≥5) group were 96.3% (n=711), 89.0% (n=626) and 71.4% (n=313), respectively. Statistically significant difference was observed among groups (P<0.01). Conclusions: The number of lymph nodes examined was an independent prognostic factor for disease-free survival after curative surgery in patients with stage Ⅰ to Ⅲ colon cancer. Incorporating the number of lymph nodes examined as a multi-categorical variable into the T and N staging system could improve prognostic predictive validity.

Production improvement of FK506 in Streptomyces tsukubaensis by metabolic engineering strategy

AIMS

Study of the effect of isoleucine on the biosynthesis of FK506 and modification of its producing strain to improve the production of FK506.

METHODS AND RESULTS

Metabolomics analysis was conducted to explore key changes in the metabolic processes of Streptomyces tsukubaensis Δ68 in medium with and without isoleucine. In-depth analysis revealed that the shikimate pathway, methylmalonyl-CoA, and pyruvate might be the rate-limiting factors in FK506 biosynthesis. Overexpression of involved gene PCCB1 in S. tsukubaensis Δ68, a high-yielding strain Δ68-PCCB1 was generated. Additionally, the amino acids supplement was further optimized to improve FK506 biosynthesis. Finally, FK506 production was increased to 929.6 mg L-1, which was 56.6% higher than that in the starter strain, when supplemented isoleucine and valine at 9 and 4 g L-1, respectively.

CONCLUSIONS

Methylmalonyl-CoA might be the key rate-limiting factors in FK506 biosynthesis and overexpression of the gene PCCB1 and further addition of isoleucine and valine could increase the yield of FK506 by 56.6%.

Improvement of FK506 production via metabolic engineering-guided combinational strategies in Streptomyces tsukubaensis

Background

FK506, a macrolide mainly with immunosuppressive activity, can be produced by various Streptomyces strains. However, one of the major challenges in the fermentation of FK506 is its insufficient production, resulting in high fermentation costs and environmental burdens. Herein, we tried to improve its production via metabolic engineering-guided combinational strategies in Streptomyces tsukubaensis.

Results

First, basing on the genome sequencing and analysis, putative competitive pathways were deleted. A better parental strain L19-2 with increased FK506 production from 140.3 to 170.3 mg/L and a cleaner metabolic background was constructed. Subsequently, the FK506 biosynthetic gene cluster was refactored by in-situ promoter-substitution strategy basing on the regulatory circuits. This strategy enhanced transcription levels of the entire FK506 biosynthetic gene cluster in a fine-tuning manner and dramatically increased the FK506 production to 410.3 mg/mL, 1.41-fold higher than the parental strain L19-2 (170.3 mg/L). Finally, the FK506 production was further increased from 410.3 to 603 mg/L in shake-flask culture by adding L-isoleucine at a final concentration of 6 g/L. Moreover, the potential of FK506 production capacity was also evaluated in a 15-L fermenter, resulting in the FK506 production of 830.3 mg/L.

Conclusion

From the aspects of competitive pathways, refactoring of the FK506 biosynthetic gene cluster and nutrients-addition, a strategy for hyper-production and potentially industrial application of FK506 was developed and a hyper-production strain L19-9 was constructed. The strategy presented here can be generally applicable to other Streptomyces for improvement of FK506 production and streamline hyper-production of other valuable secondary metabolites.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12934-021-01660-w.

Activation and discovery of tsukubarubicin from Streptomyces tsukubaensis through overexpressing SARPs

Genome sequencing has revealed that each Streptomyces contains a wide range of biosynthetic gene clusters (BGCs) and has the capability to produce more novel natural products than what is expected. However, most gene clusters for secondary metabolite biosynthesis are cryptic under normal growth conditions. In Streptomyces tsukubaensis, combining overexpression of the putative SARPs (Streptomyces antibiotic regulatory proteins) and bioactivity-guided screening, the silent gene cluster (tsu) was successfully activated and a novel bioactive anthracycline tsukubarubicin was further isolated and identified. Biological activity assays demonstrated that tsukubarubicin possessed much better antitumor bioactivities against various human cancer cell lines (especially the breast cancer cell lines) than clinically used doxorubicin. Moreover, the previously unreported gene cluster (tsu) for biosynthesis of tsukubarubicin was first characterized and detailed annotations of this gene cluster were also conducted. Our strategy presented in this work is broadly applicable in other Streptomyces and will assist in enriching the natural products for potential drug leads. KEY POINTS: • Generally scalable strategy to activate silent gene clusters by manipulating SARPs. • The novel anthracycline tsukubarubicin with potent antitumor bioactivities. • Identification and annotation of the previously uncharacterized tsu gene cluster.

A meta-analysis of dietary carbohydrate intake and inflammatory bowel disease risk: evidence from 15 epidemiology studies

BACKGROUND AND PURPOSE

epidemiological studies that assess the association of dietary total carbohydrate intake and inflammatory bowel disease risk (IBD) have yielded controversial results. Therefore, this study of various epidemiological studies was conducted in order to explore this relationship.

METHODS

a systematic literature search of the PubMed, Embase, Web of Science and Medline databases was performed up to September 2017. Cohort, case-control or cross-sectional design studies were included that reported the association of dietary carbohydrate intake and IBD risk. Summary odds ratio (OR) and the corresponding 95% CI were calculated using the random effects model.

RESULTS

a total of eight articles with 15 individual studies that included 1,361 cases were eligible according to the inclusion criteria. Dietary carbohydrate intake had a non-significant relationship with the risk of IBD (OR = 1.091, 95% CI = 0.817-1.455, I2 = 31.6%, pfor heterogeneity = 0.116). The pooled OR and 95% CI for ulcerative colitis (UC) and Crohn's disease (CD) with regard to dietary carbohydrate intake was 1.167 (0.777-1.752) and 1.010 (0.630-1.618), respectively. These associations were also non-significant in both European and Asia populations.

CONCLUSIONS

a higher dietary total carbohydrate intake had a non-significant relationship with IBD risk. Further studies with large populations are needed to verify this relationship.

Short-Term and Long-Term Outcomes of Laparoscopic Versus Open Surgery for Low Rectal Cancer

AIM

To compare the short-term and long-term outcomes of laparoscopic versus open surgery for low rectal cancer.

METHODS

Patients with low rectal cancer who underwent laparoscopic or open surgery at our department from January 2009 to December 2013 were enrolled in this retrospective study. The primary end points were 3-year local recurrence and overall and disease-free survival (DFS) rates. Secondary end points were intraoperative and postoperative outcomes.

RESULTS

Laparoscopic group had longer operative time (165.0 versus 140.0, P < .001), less blood loss (20.0 versus 40.0, P < .001), shorter length of incision (5.0 versus 18.0, P < .001), and more lymph node harvested (11.0 versus 9.0, P = .002). However, time to first flatus (P = .941), postoperative hospital stay (P = .095), postoperative complications (P = .155), and 30-day mortality (P = .683) was similar between two groups. With the median follow-up period of 65 months, the 3-year local recurrence rate was 4.3% in laparoscopic group and 7.5% in open group (P = .077); the 3-year overall and DFS rates were similar in two groups (85.9% versus 88.8%, P = .229 and 76.9% versus 79.2%, P = .448, respectively); and the overall and DFS curves were comparable between two groups (hazard ratio [HR] = 0.858, 95% confidence intervals [CI] 0.709-1.037, P = .112 and HR = 1.076, 95% CI 0.834-1.389, P = .275, respectively).

CONCLUSIONS

Laparoscopic surgery is safe and has equivalent long-term oncologic outcomes for low rectal cancer when compared to open surgery. Furthermore, large-scale, prospective randomized clinical trials are needed to confirm the present findings.

Prognostic role of the lymphocyte-to-monocyte ratio in patients undergoing resection for nonmetastatic rectal cancer

Lymphocyte-to-monocyte ratio (LMR) was associated with survival benefit in some types of cancer. The relationship between LMR and rectal cancer has not been investigated. We conducted a retrospective cohort study to assess the prognostic significance of LMR in patients with nonmetastatic rectal cancer. Patients with rectal cancer who underwent potentially curative resection between January 2009 and December 2013 were enrolled. The LMR was calculated from preoperative blood test by dividing the absolute lymphocyte counts by the absolute monocyte counts. The optimal cut-off value for LMR was calculated as the median value. On the basis of the cut-off value, patients were divided into 2 groups: low group and high group. A total of 543 patients with rectal cancer were eligible for this study. The median follow-up time for all patients was 55 months (range 6-85 months). The cut-off value of LMR was 5.13 and patients were divided into 2 groups: low group (LMR < 5.13) and high group (LMR ≥ 5.13). In the univariate and multivariate analysis, the LMR was not significantly associated with overall survival (OS) [hazard ratio (HR): 1.034, 95% confidence intervals (CIs): 0.682-1.566, P = 0.876]. When disease-free survival (DFS) was compared, univariate and multivariate analysis also indicated that the LMR was not significantly associated with DFS (HR: 0.988, 95% CI: 0.671-1.453, P = 0.950). In addition, in the subgroup analysis by tumor-node-metastasis stage, there existed no significance between LMR and OS and DFS. Although as an easy access and highly efficient laboratorial inflammatory marker, LMR cannot predict the prognosis of nonmetastatic rectal cancer patients.

Clinicopathological characteristics and prognosis of schistosomal colorectal cancer

AIM

The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors of schistosomal colorectal cancer.

METHOD

A total of 74 consecutive schistosomal colorectal cancer patients who underwent curative surgery from July 2009 to July 2012 were included in this study. The clinical and pathological characteristics of all 74 patients were analysed and univariate and multivariate analyses were performed. This study demonstrated positive correlations between the site of deposition of schistosomal eggs and certain essential variables.

RESULTS

Depositional site of schistosome eggs, carcinoembryonic antigen (CEA) level and the pathological N and T stages were statistically significantly correlated with overall survival (OS). The pathological T stage and the CEA level were independent prognostic factors for OS. The site of deposition of schistosome eggs was positively correlated with the T and N stages, tumour size, the CEA level and the resection margins.

CONCLUSIONS

Schistosome eggs might be associated with tumorigenesis. The site of deposition of schistosome eggs was statistically significantly correlated with OS but it was not an independent prognostic factor for OS. It was, however, correlated with the depth of the tumour. The presence of schistosoma eggs at the margin did not affect the patient's prognosis or anastomotic healing. The existing standard surgical approach was equally applicable to schistosomal colorectal cancer. It was not necessary to expand the scope of surgical resection.

Molecular epidemiology of genogroup II norovirus infection among hospitalized children with acute gastroenteritis in Suzhou (Jiangsu, China) from 2010 to 2013

Noroviruses (NoVs) are the most common cause of acute gastroenteritis in both sporadic and outbreak cases. Genotyping and recombination analyses were performed in order to help getting more knowledge of the distribution and genetic diversity of NoVs in Suzhou, located in Jiangsu province of China. All stool samples were collected from hospitalized children younger than 5 years old with acute gastroenteritis. For genotyping, the open reading frame (ORF) 1 and ORF2 were partially amplified and sequenced. 26.9% of stool samples were positive for genogroup II NoVs. The most common genotype was GII.4 and its variants included Den Haag-2006b, New Orleans-2009, and Sydney-2012. The Den Haag-2006b variants predominated during 2010-2012. In 2013, it was replaced by the Sydney-2012 variant. The second most common genotype was GII.12/GII.3. NoVs could be detected throughout the year, with GII.4 and GII.12/GII.3 coexisting during the cold months, and GII.4 was the main genotype during the warm months. The highest prevalence of NoV was detected in young children aged <24 months. Patients infected with GII.4 had a higher chance of getting moderate fever than other NoV-positive patients, while those infected with GII.12/GII.3 tended to have a mild degree of fever. NoV is an important pathogen responsible for viral gastroenteritis among children in Suzhou. Analyses of NoV circulating between 2010 and 2013 revealed a change of predominant variant of NoV GII.4 in each epidemic season and intergenotype recombinant strains represented an important part.

Identification of smut-responsive genes in sugarcane using cDNA-SRAP

Sugarcane smut, caused by the fungus Sporisorium scitamineum, is one of the main diseases that affect sugarcane worldwide. In the present study, the cDNA-SRAP technique was used to identify genes that are likely to be involved in the response of sugarcane to S. scitamineum infection. In total, 21 bands with significant differential expression during cDNA-SRAP analysis were cloned and sequenced. Real-time qPCR confirmation demonstrated that expression of 19 of these 21 differential bands was consistent with the expression observed during cDNA-SRAP analysis, with a deduced false positive rate of 9.5%. Sequence alignment indicated that 18 of 19 differentially expressed genes showed homologies from 19% to 100% to certain genes in GenBank, including the following genes: topoisomerase (EU048780), ethylene insensitive (EU048778), and tetraspanin (EU048770). A real-time qPCR assay showed that during 0-72 h after pathogen infection, expression of the topoisomerase and the ethylene insensitive genes was upregulated, whereas expression of the tetraspanin gene was downregulated, identical to the expression patterns observed under salicylic acid treatment. Therefore, all three genes are thought to play a role during S. scitamineum challenge, but with different functions. To our knowledge, this is the first report on the application of cDNA-SRAP in differential gene expression analysis of sugarcane during a sugarcane-S. scitamineum interaction. The results obtained also contribute to a better understanding of the molecular mechanisms associated with sugarcane-S. scitamineum interactions.

Hospital-Based Surveillance of Rotavirus Diarrhea in the People's Republic of China, August 2003-July 2007

Rotaviruses cause acute diarrhea worldwide. Previous studies of rotavirus diarrhea in China found that rotavirus infection is the most common cause of severe diarrhea in young children. In the present study, surveillance of rotavirus diarrhea was conducted involving 9549 children aged <5 years who were admitted for treatment of diarrhea at 11 sentinel hospitals in China from August 2003 through July 2007. Group A rotavirus was detected in 3749 (47.8%) of the 7846 fecal specimens by using enzyme-linked immunosorbent assay. Rotavirus isolates were characterized by reverse-transcriptase polymerase chain reaction to determine G and P genotypes. All the strains that are common worldwide were detected; G3P[8] was the most common. An unusual G5 strain was detected in 2 specimens. Of all episodes of rotavirus diarrhea, 94% occurred during the first 2 years of life, peaking at 6-23 months of age. Our findings indicate that globally common rotavirus strains continue to be a major cause of severe childhood diarrhea in China. Introduction of routine immunization with effective rotavirus vaccines would substantially reduce this burden.

[Distribution signature analysis between intussusception and rotavirus diarrhea in young children]

OBJECTIVE

To investigate the annual incidence rate of intussusception over a 5-year period in Suzhou and to determine whether there was a potential link between intussusception rotavirus diarrhea.

METHODS

Outpatient and inpatient data from 1999 through 2003 retrospectively were reviewed for young children (< 2 year old) whose diagnosis was confirmed by ultrasonography or radiography and patients were reduced by air enema or surgery. From September 2001, to August 2003, inpatients with diarrhea (< 2 year old) were detected rotavirus antigen in the stool by ELISA technology.

RESULTS

From 1999 through 2003, 1101 cases were reported in children below 2 years old. The incidence rate of intussusception under 1 year age each year was 275.3, 338.2, 547.0, 515.3, and 425.4 per 100,000 child years respectively (the average annual incidence was 418.1 per 100,000 child years), and the incidence of intussusception increased over time from 1999 to 2003. A peak age distribution of intussusception was infants 4 to 10 months old (692/1101, 62.85%) and mean age was 9.62 +/- 5.65 months, which were greatly different from those of patients with rotavirus diarrhea, whose peak age distribution was 5 to 16 months old (252/331, 76.13%), and mean age was 11.42 +/- 5.14 months (Z = 6.90, P < 0.01). The peak month distribution of intussusception was from April to August (595/1101, 54.04%), which was distinct from that of patient with rotavirus diarrhea, whose peak month distribution was between October and January (232/331, 70.09%). Test: chi2 = 226.06, P < 0.001.

CONCLUSION

The annual incidence rate of intussusception for < 1 year of age was 418.1 per 100,000 child years in Suzhou. We found no epidemiologic evidence for an association between intussusception and rotavirus diarrhea.