MiR-7-5p/KLF4 signaling inhibits stemness and radioresistance in colorectal cancer

Resistance to radiotherapy remains a major unmet clinical obstacle in the treatment of locally advanced rectal cancer. Cancer stem cells (CSCs) are considered to mediate tumor development and radioresistance. However, the role of CSCs in regulating resistance to radiotherapy in colorectal cancer (CRC) remains largely unknown. We established two radioresistant CRC cell lines, HCT116-R and RKO-R, using fractionated irradiation. Analysis using miRNA sequencing and quantitative real-time PCR confirmed lower levels of miR-7-5p in both of the radioresistant cells compared to their parental cells. Subsequently, we validated that miR-7-5p expression was decreased in cancerous tissues from radiotherapy-resistant rectal cancer patients. The Cancer Genome Atlas (TCGA) database analyses revealed that low miR-7-5p expression was significantly correlated with poor prognosis in CRC patients. Overexpression of miR-7-5p led to a rescue of radioresistance and an increase in radiation-induced apoptosis, and attenuated the stem cell-like properties in HCT116-R and RKO-R cells. Conversely, knocking down miR-7-5p in parental HCT116 and RKO cells suppressed the sensitivity to radiation treatment and enhance cancer cell stemness. Stemness-associated transcription factor KLF4 was demonstrated as a target of miR-7-5p. Rescue experiments revealed that miR-7-5p/KLF4 axis could induce radiosensitivity by regulating CSCs in colorectal cancer cells. Furthermore, we used CRC tumor tissues which exhibited resistance to neoadjuvant radiotherapy to establish a patient-derived xenograft (PDX) mouse model. Tail vein injection of magnetic nanoparticles carrying miR-7-5p mimics into the PDX mice significantly inhibited tumor growth with or without irradiation treatment in vivo. Our current studies not only demonstrate an anti-cancer function of miR-7-5p in regulating CSC properties and radiosensitivity in colorectal cancer, but also provide a novel potential strategy for delaying or reverse radiation resistance in preoperative radiotherapy of CRC patients.

Survival outcomes analysis according to mismatch repair status in locally advanced rectal cancer patients treated with neoadjuvant chemoradiotherapy

Background

The predictive role of mismatch repair (MMR) status for survival outcomes and sensitivity in neoadjuvant chemoradiotherapy settings for patients with locally advanced rectal cancer (LARC) has been inconclusive.

Methods

A retrospective cohort of patients with LARC treated with neoadjuvant chemoradiotherapy (nCRT) was recruited. After adjusting for baseline characteristics, we used propensity score matching to reduce the effect of potential confounding factors on MMR status. The primary analysis was based on overall survival as the more important endpoint.

Results

This study included 269 patients. Patients with defective MMR (dMMR) were younger (58.5% vs. 60.0%, p=0.0274) and had lower body mass indices (p=0.0091), higher differentiation grades (p=0.0889), and more advanced rectal cancers (clinical T4 or T4b, p=0.0851; M1, p=0.0055) than those with proficient MMR (pMMR). However, propensity score-matched patients with dMMR (p=0.0013) exhibited superior overall survival, even in the M1 subgroup. More importantly, patients with proficient MMR who undergo early pathological downstaging, especially lymph node pathological downstaging, can achieve a prognosis similar to that of patients with dMMR.

Conclusion

The clinical significance of this retrospective study mainly includes two points: (1) Data from our study confirmed that LARC patients with dMMR status had better overall survival rates after nCRT, even in the M1 subgroup. (2) Similar survival outcomes were observed in older and female patients with early lymph node pathological downstaging, regardless of dMMR or pMMR.

Priority Management of Henle Trunk in Cranial-to-Caudal Approach for Laparoscopic Right Hemicolon Cancer Surgery

This study aimed to compare the short-term clinical efficacy between prior and traditional approach of Henle trunk in laparoscopic right hemicolectomy (LRH) for right colon cancer. A total of 161 patients underwent LRH for right colon cancer between June 2018 and December 2020 by the same group of physicians. The prior approach of Henle trunk (priority group) was used in 82 patients and traditional approach in 79 (traditional group). The demographics and clinicopathological characteristics were recorded and retrospectively analyzed. As compared to the traditional group, the mean blood loss reduced significantly [73.84 ± 17.31 mL vs. 83.42 ± 30.16 mL; P = 0.001], the operation time was markedly shorter [151.35 ± 6.75 min vs. 159.13 ± 18.85 min; P = 0.014], and the intraoperative vascular injury rate was significantly lower [6.1% (5/82). vs. 17.7% (14/79); P = 0.022]. There were no significant differences in the postoperative complications, first exhaust time, first defecation time, drainage time, postoperative hospital stay, quality evaluation of surgical specimens and pathological findings between two groups. Our study shows that the priority management of Henle trunk in the LRH for right colon cancer is a safe and feasible procedure with less blood loss, shorter operation time and lower intraoperative vascular injury rate.

Decreased E2F2 Expression Correlates with Poor Prognosis and Immune Infiltrates in Patients with Colorectal Cancer

Growing evidence has revealed that the E2F family of transcription factor 2 (E2F2) participates in the tumorigenesis and progression of various tumors, but its role in colorectal cancer (CRC) remains largely unknown. Herein, the aim of our study was to investigate the exact role of E2F2 in CRC. The expression levels of E2F2 in CRC were appraised based on the Tumor Immune Estimate Resource (TIMER), Oncomine, The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO) database. The results were further confirmed using CRC tumor tissues and normal controls by experimental assays including immunohistochemistry, qRT-PCR and western blot. The survival analysis of E2F2 in CRC was analyzed using PrognoScan database and TCGA data sets. In addition, the functional roles of E2F2 were examined by Gene Set Enrichment Analysis (GSEA) and immune infiltration analysis. Our results illustrated that E2F2 was significantly downregulated in CRC samples. The low E2F2 expression in CRC was prominently correlated with N, M stage and pathological stage. Decreased E2F2 expression had an unfavorable overall survivial (OS), disease free survival (DFS), disease specific survival (DSS) and progress free interval (PFI). Multivariate cox regression showed E2F2 could be an independent prognostic factors of OS in CRC. Receiver operating characteristic (ROC) analysis showed that E2F2 may serve as a potential diagnostic biomarker for CRC patients. GSEA disclosed that E2F2 was probably involved in several pathways, including ATR pathway, ATM signalling pathway, mismatch repair, base excision repair, homologous recomibination, Fanconi Anemia pathway, multicancer invasiveness signature, and cancer stem cells. Moreover, E2F2 was significantly correlated with the infiltration level of Th2, aDC, Th17, NK CD56dim, T helper and pDC cells. The current study demonstrates that decreased E2F2 expression is closely associated with poor prognosis and immune cell infiltration in CRC, which can be a promising independent prognostic biomarker and potential treatment target for CRC.

Expression and mechanism of exosome-mediated A FOXM1 related long noncoding RNA in gastric cancer

BACKGROUND

Forkhead box protein M1 (FOXM1) is an oncogene regulating tumor growth and metastasis. Exosome was suggested to mediate cell communication by delivering active molecules in cancers. However, the existence of FOXM1 in circulating exosomes and the role of exosome FOXM1 in gastric cancer (GC) were not clear. This study aims to investigate the potential role of FOXM1 related long noncoding RNA (FRLnc1) in exosomes in GC.

RESULTS

The prepared CD63 immunomagnetic beads (CD63-IMB) had the characteristics of good dispersity and high magnetic response. The isolated exosomes were presented with elliptical membranous particles under a transmission electron microscope (TEM), with the particle size of 89.78 ± 4.8 nm. Western blot (WB) results showed that the exosomes were rich in CD9 and CD81. The Dil-labeled exosomes were distributed around cytoplasm and nucleus of cells by imaging flow cytometry (IFC) analysis. The results of quantitative real-time PCR (qRT-PCR) revealed that the FRLnc1 expressions were up-regulated in GC cells, tumor tissues, and serum of GC patients. An obviously up-regulated FRLnc1 expression was found in serum exosomes of GC patients. Up-regulation of FRLnc1 expression was closely correlated to lymph node metastasis (LNM) and TNM stage with the combination of relevant clinicopathological parameter analysis. The in vitro functional analyses demonstrated that FRLnc1 knockdown by RNA interference suppressed cell proliferation and migration in HGC-27 cells, whereas FRLnc1 overexpression promoted cell proliferation and migration in MKN45 cells. After exosome treatment, the FRLnc1 expression was significantly increased in MKN45 cells, and the MKN45 cells showed increased ability of proliferation and migration.

CONCLUSION

GC cells-derived exosomes played roles in promoting the growth and metastasis of GC by transporting FRLnc1, suggesting that FRLnc1 in the exosomes may be a potential biomarker for the diagnosis and treatment of GC. The delivery of FRLnc1 by the exosomes may provide a new way for the treatment of GC. Trial registration 2020-KYSB-094. Registered 23 March 2020-Retrospectively registered.

Expert consensus on multidisciplinary therapy of colorectal cancer with lung metastases (2019 edition)

The lungs are the second most common site of metastasis for colorectal cancer (CRC) after the liver. Rectal cancer is associated with a higher incidence of lung metastases compared to colon cancer. In China, the proportion of rectal cancer cases is around 50%, much higher than that in Western countries (nearly 30%). However, there is no available consensus or guideline focusing on CRC with lung metastases. We conducted an extensive discussion and reached a consensus of management for lung metastases in CRC based on current research reports and the experts' clinical experiences and knowledge. This consensus provided detailed approaches of diagnosis and differential diagnosis and provided general guidelines for multidisciplinary therapy (MDT) of lung metastases. We also focused on recommendations of MDT management of synchronous lung metastases and initial metachronous lung metastases. This consensus might improve clinical practice of CRC with lung metastases in China and will encourage oncologists to conduct more clinical trials to obtain high-level evidences about managing lung metastases.

Basic transcription factor 3 expression silencing attenuates colon cancer cell proliferation and migration in vitro

Basic transcription factor 3 (BTF3) is an RNA polymerase II transcription factor that also regulates apoptosis. Numerous studies have identified that BTF3 is aberrantly expressed in several types of tumor. However, the function of BTF3 in colorectal cancer remains unknown. The aim of the present study was to assess the function of BTF3 during colon cancer tumorigenesis. Applying a lentivirus-transfected short hairpin RNA approach, expression of BTF3 was dysregulated in the colon cancer HCT116 and HT-29 cell lines; knockdown efficiency was verified using the quantitative polymerase chain reaction and western blotting. To determine the function of BTF3 in colon cancer, cell proliferation was assessed using an MTT assay, cell apoptosis and the cell cycle were assessed using flow cytometry, and cell migration was assessed using a Transwell assay. Knockdown of BTF3 inhibited cell proliferation, possibly because BTF3 knockdown induced cell early apoptosis and arrested cells in G₀-G₁ phase. BTF3 knockdown also inhibited cell migration. The results of the present study identified that BTF3 expression is associated with colon cancer progress, and BTF3 may therefore be a molecular marker for diagnosis and treatment outcomes of human colon cancer.

[Feasibility analysis on 3D laparoscopic surgery via transrectal extraction of specimens without abdominal incision in the treatment of slow transit constipation]

OBJECTIVE

To investigate the safety and feasibility of 3D laparoscopic surgery via transrectal extraction of specimens without abdominal incision in the treatment of slow transit constipation (STC).

METHODS

From May 2015 to January 2017, 8 STC patients (6 females and 2 males) with informed consent were selected to receive subtotal colectomy with 3D laparoscopy as the no-incision incision group, in which the initial part of ascending colon and rectum were end-to-end anastomosed directly after extraction of the specimen through the rectum. Twelve STC patients (9 females and 3 males) undergoing traditional subtotal colectomy with 3D laparoscopy were selected as the traditional group by case matching method (gender, age, BMI, the difference of receiving operation time less than 12 months, same surgeon team). Perioperative parameters (operation duration, intraoperative blood loss, exhausting time, postoperative hospital stay, complications, postoperative pain score and additional pain management), inflammation index at postoperative day 1 and day 3 (leukocyte, procalcitonin, interleukin 6, C-reactive protein), postoperative peritoneal infection, wound healing, short-term and long-term efficacy, patient satisfaction evaluation (subjective hundred-mark system) at postoperative one year were compared between two groups.

RESULTS

There were no significant differences between two groups in operation duration, intraoperative blood loss, exhausting time, postoperative hospital stay and morbidity of complication (all P>0.05). Significantly lower pain scores at postoperative 6-hour (median 3.0 vs. 4.5, U=23.0, P=0.042), lower ratio of additional analgesic at postoperative day 1(1/8 vs. 7/12, P=0.040) were found in the no-incision group. Leukocyte level at postoperative day 1 was significantly lower in the no-incision group [(11.0±3.5)×10⁹/L vs. (14.7±3.6)×10⁹/L, t=-2.281, P=0.035]. C-reactive protein concentration at postoperative day 3 was not significantly different between two groups but with different trend [median 78.1(0.1 to 154.0) mg/L vs. 22.0 (7.0 to 55.9) mg/L,U=33.0, P=0.047]. There were no significant differences of interleukin-6 and procalcitonin between two groups(all P>0.05). All the patients had follow-up for 14-31 months. Subjective effectiveness score was 90±9 in the no-incision group and 94±6 in the traditional group without significant difference(t=-1.099, P=0.286). No long-term complications associated with abdominal infection was observed in the no-incision group.

CONCLUSION

3D laparoscopic subtotal colectomy via transrectal extraction of specimens without abdominal incision in the treatment of STC has similar short-term and long-term efficacies compared with traditional laparoscopic assisted surgery, and does not increase the probability of abdominal contamination.

Survival time and prognostic factors of patients with initial noncurative colorectal liver metastases

The true survival benefit of different curative strategies involving type of operative procedure and timing for patients with initial noncurative colorectal liver metastases remains uncertain. The goal of this study was to examine the effect of primary tumor resection on patients' survival and to clarify the predictive factors related to overall survival (OS).This was a retrospective study that included 219 patients with initial noncurative colorectal liver metastases without extrahepatic disease. The clinicopathological characteristics of patients and their survival were examined. Survival analysis was performed using the Kaplan-Meier method. All variables associated with P <.05 in univariate analysis were included in multivariate analysis using a Cox proportional-hazard regression model.The 1-, 3-, 5-year OS rates of patients with simultaneous liver resection were 79.1%, 39.1%, and 28.4%, respectively, and those of patients with staged liver resection were 83.3%, 46.7%, and 36.8%, respectively (P = .380). The 1-, 3-, 5-year OS rates of patients with primary tumor resection were 57.0%, 18.2%, and 12.3%, respectively, while for the patients without primary tumor resection were 38.9%, 5.6%, and 0%, respectively (P = .012). Independent prognostic factors for OS were carbohydrate antigen19-9, primary tumor resection, tumor differentiation, and adjuvant chemotherapy.No difference in OS was observed between simultaneous liver resection and staged liver resection, while primary tumor resection was beneficial to noncurative colorectal liver metastases.

[Protective measures in laparoscopic resection for upper or mid rectal cancer and sigmoid colon cancer with transrectal specimen extraction surgery]

OBJECTIVE

To introduce the use of a self-made specimen protective sleeve in laparoscopic resection for upper or mid rectal cancer and sigmoid colon cancer with transrectal specimen extraction surgery and the improvement of implantation method, so as to avoid and reduce bacterial contamination and tumor cell dissemination in abdominal cavity.

METHODS

During June 2015 and May 2017, 48 cases of high located rectal or sigmoid colon cancer were operated laparoscopically with natural orifices specimen extraction surgery (NOSES) using a self-made specimen protecting sleeve. Operation indication: (1) Rectum and sigmoid colon cancer with the distance of more than 6 cm from tumor inferior margin to dentate line. (2) The maximum diameter of intestine together with mesangial and tumor <7 cm by intraoperative judgment. (3) No anal and distal rectal surgery, no anorectal stenosis or lack of expansion capacity caused by trauma. (4) No ulcerative colitis, Crohn's disease or radiation proctitis. After transecting the rectum, the specimen protective sleeve was inserted through the right lower 12 mm main Trocar (This sleeve was tailored from the laparoscopic protective sleeve produced by China 3L Corporation, which was intercepted with 25-35 cm from one end of the sleeve according to the length of distal rectal retention. One end was ligated and the other was open with a ligature band. About 5 ml paraffin oil was used to rinse and lubricate during the operation). The rectal stump retained 7-8 cm in abdominal cavity. The transanal ligation part of the protective sleeve was cut off, then the stapler nail seat was inserted and specimen was pull out through the sleeve and rectum.

RESULTS

There were 30 males and 18 females. The average age was (64.5±14.1) years, the BMI was (25.4±3.9) kg/m², the tumor diameter was (3.3±1.1) cm, the maximum diameter of specimen was (5.4±1.5) cm and the length of specimen was (18.6±4.3) cm. Among these 48 cases, specimens of 36 patients were pulled out through inside of the sleeve easily, while specimens of 12 patients were quite difficult with resistance. Of 12 cases, 7 needed the help of transverse forceps, 4 needed to make 1 cm incision in pull-through bowel and insert a suction to decrease the volume of large specimens with gathering of gas and fluid, and 1 received small abdominal incision to remove specimen and perform intestinal reconstruction due to big specimen (the diameter of tumor and mesentery was 7.5 cm). Specimen tears of 6 patients didn't result in dissemination thanks to the specimen protecting sleeve. The operation time was (113.2±76.1) min, the bleeding amount was (38.5±17.3) ml, the time to first oral intake was (47.9±4.4) h, and the postoperative hospitalization length was (8.5±1.7) d. Anastomotic leakage occurred in 1 case (2.1%). No intra-abdominal and trocar infection, and obstruction were found.

CONCLUSION

The use of protective sleeve and the improvement of the method of intraperitoneal implantation can effectively reduce the abdominal contamination during the specimen extraction. It can be applied to big specimens as well.

[Study on the relationship between tumor regression grade and lymph node regression grade]

OBJECTIVE

To investigate the relationship between tumor regression grade (TRG) and lymph node regression grade (LRG) after neoadjuvant chemoradiotherapy (CRT) for rectal cancer and its clinical implication.

METHODS

Clinicopathological data of 176 rectal cancer patients undergoing radical excision after neoadjuvant CRT from January 2005 to December 2013 in our department were retrospectively analyzed.

INCLUSION CRITERIA

(1) Radiology indicated locally advanced low rectal cancer and patients had strong desire to preserve the sphincter before neoadjuvant CRT; (2) there was no definite metastatic lesion before neoadjuvant CRT; (3) patients received whole course of neoadjuvant CRT (regular radiotherapy plus synchronous fluorouracil-like drugs chemotherapy); (4) patients underwent radical operation after neoadjuvant CRT. Patients with short-course CRT and emergency surgery were excluded. TRG and LRG of postoperative specimens (including tumor and lymph nodes) were carried out based on the percentage of the fibrosis and the cancer residue. No cancer residue was defined as TRG1 and LRG1; rare cancer cell residue as TRG2 and LRG2; fibrosis growth over residual cancer as TRG3 and LRG3; residual cancer growth over fibrosis as TRG4 and LRG4; absence of regressive changes as TRG5 and LRG5; and normal lymph nodes as LRG0. Spearman correlation test was used to assess the correlation between TRG and LRG.

RESULTS

Of 176 patients, 111 were men and 65 were women. The mean age was (53.9±13.0) years. The number of patients with stage I(, II(, and III( before operation was 10, 49 and 62 while other 55 patients were unknown. Transabdominal low anterior resection (LAR) was performed in 118 cases and abdominal-perineal resection(APR) in 47 cases following the principle of total mesorectal excision (TME). Postoperative pathology of specimens revealed that the number of patients from TRG1 to TRG5 was 19 (10.8%), 25 (14.2%), 66 (37.5%), 47 (26.7%), 19 (10.8%), and from LRG0 to LRG5 was 35 (19.9%), 68 (38.6%), 10 (5.7%), 14 (8.0%), 15(8.5%), 34 (19.3%), respectively. TRG was correlated to LRG (P=0.005) while the Spearman correlation coefficient was only 0.24. The analysis of subgroup without LRG1 also showed that TRG was correlated to LRG(P=0.0005) and the Spearman correlation coefficient was 0.40.

CONCLUSIONS

TRG can not represent LRG. Therefore, both TRG and LRG should be assessed when evaluating the response of rectal cancer to neoadjuvant CRT.

A Scoring System to Predict the Development of Bone Metastasis After Radical Resection of Colorectal Cancer

BACKGROUND/AIM

To develop a scoring system to predict bone metastasis after radical resection within 5 years.

PATIENTS AND METHODS

We evaluated the patient records of 1,749 patients, of whom 50 patients developed bone metastasis. Treatment-related factors (age, gender, localization, histology, preoperative carbohydrate antigen 199 level, T-stage, lymph node metastasis (LN) and pulmonary metastasis (PM)) were analyzed.

RESULTS

We found three independent risk factors, namely rectal cancer (p=0.038), LN (p=0.006) and metachronous PM (p<0.001). Scoring was conducted by adding zero or one point from each variable and resulted in four groups of 0, 1, 2 or 3 points. Three groups were formed, with 0-1 points vs. 2 points vs. 3 points (1.5% vs. 6.6% and 10.5%, p<0.001).

CONCLUSION

This new score can help clinicians identify patients at risk for continuous monitoring and optimize surveillance to be able to detect and treat bone metastases very early in order to avoid skeletal complications.

Lentivirus-mediated RNA interference of tripartite motif 68 inhibits the proliferation of colorectal cancer cell lines SW1116 and HCT116 in vitro

Colorectal cancer is one of the most common types of cancer worldwide. Previous studies have revealed that certain members of tripartite motif (TRIM) proteins are involved in carcin ogenesis regulation, but little is known about the function of TRIM68 in human colorectal cancer. To investigate the role of TRIM68 in colorectal cancer SW1116 and HCT116 cell lines, the present study conducted lentivirus-mediated knockdown against TRIM68 and demonstrated that depletion of TRIM68 notably inhibits colorectal cancer cell proliferation and colony formation ability. Cell cycle arrest in the G0/G1 phase and cycle accumulation in sub-G1 phase provided evidence that TRIM68 may participate in the regulation of colorectal cancer tumorigenesis. The results revealed the significant role of TRIM68 in regulating colorectal cancer cell mitosis and indicated that TRIM68 may be a promising therapeutic target.

[Analysis of risk factors for bone metastasis after radical resection of colorectal cancer within 5 years]

OBJECTIVE

To investigate the risk factors of metachronous bone metastasis after radical resection of colorectal cancer within 5 years.

METHODS

Clinical data of 1 749 patients with colorectal cancer, of whom 50(2.8%) patients developed metastasis to bone after operation, in the Department of Colorectal Surgery, Changhai Hospital of The Second Military Medical University from January 2001 to December 2010 were analyzed retrospectively. Univariate and multivariate analysis were performed to find the risk factors of metachronous bone metastasis from colorectal cancer using Chi square test and Logistic regression, respectively.

RESULTS

Of 50 colorectal cancer cases with bone metastasis, 29 were male and 21 were female. The age was ≥ 60 years old in 28 cases. Tumors of 36 cases were located in the rectum and of 14 cases located in the colon. Pathology examination showed 43 cases were adenocarcinomas, 7 cases were mucinous adenocarcinoma. Forty-two cases had T3-4 stage lesions, 30 cases had lymph node metastasis, 14 cases had pulmonary metastasis, and 5 cases had liver metastasis. Univariate Chi square test indicated that factors associated with the metachronous bone metastasis of colorectal cancer within 5 years were tumor site (χ²=4.932, P=0.026), preoperative carbohydrate antigen 199 (CA199) level (χ²=4.266, P=0.039), lymph node metastasis (χ²=13.054, P=0.000) and pulmonary metastasis(χ²=35.524, P=0.000). The incidence of bone metastasis in patients with rectal cancer (3.6%, 36/991) was higher compared to those with colon cancer (1.8%, 14/758). The incidence of bone metastasis in patients with higher(> 37 kU/L) preoperative serum CA199 level (4.9%, 12/245) was higher compared to those with lower serum CA199 level (2.5%, 38/1504). The incidence of bone metastasis in patients with lymph node metastasis(4.8%,30/627) and pulmonary metastasis (11.6%, 14/121) was significantly higher compared to those without lymph node metastasis (1.8%, 20/1122) and pulmonary metastasis(2.2%, 36/1628), respectively. Logistic multivariate analysis showed that rectal cancer(OR:0.508, 95%CI:0.268 to 0.963, P=0.038), lymph node metastasis (OR:2.291, 95%CI:1.273 to 4.122, P=0.006) and metachronous pulmonary metastasis(OR:4.796, 95%CI:2.473 to 9.301, P=0.000) were the independent risk factors of metachronous bone metastasis of colorectal cancer within 5 years.

CONCLUSION

Patients with rectal cancer, lymph node metastasis and metachronous pulmonary metastasis are high risk groups of metachronous bone metastasis after radical resection of colorectal cancer within 5 years.

Periostin expression in intra-tumoral stromal cells is prognostic and predictive for colorectal carcinoma via creating a cancer-supportive niche

Periostin (POSTN) expression in cancer cells and circulation has been related to poor prognosis of colorectal carcinoma (CRC). However, the role of POSTN expressed in intra-tumoral stroma on CRC progression remains largely unknown. This study enrolled 1098 CRC patients who received surgical treatment in Shanghai and Guangzhou, Mainland China. In Shanghai cohort, immunohistochemistry score of stromal POSTN expression increased consecutively from adjacent mucosa, primary CRC tissues, to metastatic CRC tissues (P < 0.001), while medium- and high-stromal POSTN expression, rather than epithelial POSTN expression, independently predicted unfavorable prognoses of CRC, adjusted for covariates including TNM stage and postoperative chemotherapy in multivariate Cox models. The results in Shanghai cohort were faithfully replicated in Guangzhou cohort. Stromal POSTN expression dose-dependently predicted an unfavorable prognosis of stage III CRC patients with postoperative chemotherapy in both cohorts. POSTN derived from colonic fibroblasts or recombinant POSTN significantly promoted proliferation, anchorage independent growth, invasion, and chemo-resistance of CRC cells; whereas these effects were counteracted via targeting to PI3K/Akt or Wnt/β-catenin signaling pathway. CRC cell RKO-derived factor(s) significantly induced POSTN production in colonic fibroblasts and autocrine POSTN promoted proliferation, migration, and anchorage independent growth of fibroblasts. Conclusively, stromal POSTN is prognostic and predictive for CRC via creating a niche to facilitate cancer progression. Targeting POSTN-induced signaling pathways may be therapeutic options for metastatic or chemoresistant CRC.

Combination with intravenous iron supplementation or doubling erythropoietin dose for patients with chemotherapy-induced anaemia inadequately responsive to initial erythropoietin treatment alone: study protocol for a randomised controlled trial

INTRODUCTION

Erythropoietin (EPO) is a commonly used option in the treatment of chemotherapy-induced anaemia (CIA). However, ∼30-50% of patients fail to achieve an adequate response after initial treatment. Prior studies have demonstrated that intravenous iron might synergistically improve therapeutic response to EPO treatment in this patient population.

METHODS AND ANALYSIS

We will perform this multicentre, randomised, open-label, parallel-group, active controlled non-inferiority study to compare the two combination therapies of EPO plus intravenous iron regimen versus doubling the dose of EPO in patients with CIA who have an inadequate response to initial EPO treatment at a routine dose. A total of 603 patients with an increase in haemoglobin (Hb) <1 g/dL will be enrolled and randomised to one of the three study treatment groups at a 1:1:1 ratio Group 1: EPO treatment at the original dose plus intravenous iron dextran 200 mg every 3 weeks (Q3W) for 15 weeks; Group 2: EPO treatment at the original dose plus intravenous iron dextran 100 mg, twice a week for 5 weeks; Group 3: the control group, doubling the EPO dose without preplanned iron supplementation. The primary outcome measure to compare is the Hb response rate at week 15 and the secondary end points involve therapeutic blood transfusions. Time-to-progression, adverse events and quality of life will also be evaluated.

ETHICS AND DISSEMINATION

All participants will provide informed consent; the study protocol has been approved by the independent ethics committee of Shanghai East Hospital. This study would clearly demonstrate the potential benefit of combining epoetin treatment with intravenous iron supplementation. Findings will be shared with participating hospitals, policymakers and the academic community to promote the clinical management of CIA in China.

TRIAL REGISTRATION NUMBER

NCT02731378.

[Assessment of the risk factors relating to lymph node metastasis in rectal cancer after neoadjuvant chemoradiotherapy and the clinical significance]

OBJECTIVE

To identify the risk factors associated with lymph node metastasis in rectal cancer after neoadjuvant chemoradiotherapy (CRT).

METHODS

From January 2005 to December 2013, the clinical data of 178 patients with advanced rectal cancer undergoing radical excision after neoadjuvant CRT in our department were reviewed retrospectively. A total of 11 clinicopathologic factors relating to lymph node metastasis were studied using univariate and multivariate Logistic regression analyses.

RESULTS

There were 74(41.6%) cases with lymph node metastasis, while 104 cases without lymph node metastasis. Univariate analysis showed that age(P=0.000 2), post-CRT CEA level(P=0.011 2), ypT stage(P=0.000 0), pathologic type(P=0.004 0), and tumor regression grade(TRG)(P=0.033 8) were significantly associated with lymph node metastasis. Multivariate analysis showed that age(OR=2.385, 95% CI:1.372 ~ 4.147, P=0.002 1), post-CRT CEA level(OR=2.310, 95% CI:1.005 ~ 5.307, P=0.048 6) and ypT stage(OR=2.592, 95% CI:1.236 ~ 5.432, P=0.011 7) were independent risk factors. However, 15.8% of the patients who achieved TRG1 had lymph node metastasis and TRG failed to independently correlate with lymph node metastasis in rectal cancer after neoadjuvant CRT.

CONCLUSIONS

There was a higher ratio of lymph node metastasis in rectal cancer patients who were young, CEA≥5 μg/L or deep invasion after neoadjuvant CRT. Therefore, neoadjuvant CRT should be carefully considered in these patients.

[Analysis of the factors in the disease-free interval of metachronous pulmonary metastasis from rectal cancer]

OBJECTIVE

To investigate the factors in the disease-free interval (DFI) of metachronous pulmonary metastasis from rectal cancer.

METHODS

Clinical data of 92 patients with metachronous pulmonary metastasis from rectal cancer in the Department of Colorectal Surgery at the Changhai Hospital of the Second Military Medical University from January 2001 to December 2013 were analyzed retrospectively. Univariate and multivariate analysis were performed to find the factors affecting disease-free interval of metachronous pulmonary metastasis from rectal cancer using Log-rank test and Cox proportional hazards model, respectively.

RESULTS

The median age of all the cases was 61 (range, 26-81) years. Of the 92 cases, 59 were males and 33 were females. Thirty-six cases were confirmed to have <5 cm distance from lower margin to dentate line. Forty-four cases were examined to have 5 μg/L carcinoembryonic antigen(CEA) level. Of these cases reviewed pathologically, 69 cases were adenocarcinoma, 23 were mucinous adenocarcinoma; 19 cases had stage T1-2 lesions, 73 had stage T3-4 lesions; 43 cases had stage N0 metastasis, 49 had stage N1-2 metastasis. Thirty cases received preoperative radiotherapy, 63 cases received postoperative chemotherapy. The median follow up time of all the cases was 62(range, 3-140) months. The DFI of all the cases was (25.9±21.0) months. Univariate Log-rank test indicated that the factors associated with the disease-free interval of metachronous pulmonary metastasis of rectal cancer were location of the tumor(χ(2)=4.496, P=0.034), preoperative CEA level (χ(2)=5.553, P=0.018), T stage (χ(2)=5.796, P=0.016), N stage (χ(2)=6.780, P=0.009), preoperative neoadjuvant radiotherapy (χ(2)=11.718, P=0.001) and postoperative adjuvant chemotherapy (χ(2)=9.214, P=0.002). A shorter distance from lower margin to dentate line(<5 cm), a lower preoperative CEA level(<5 μg/L), advanced T stage lesions(T3-4), advanced N stage metastasis(N1-2), no use of preoperative radiotherapy and use of postoperative chemotherapy were associated with shorter DFI of patients with metachronous pulmonary metastasis from rectal cancer. Multivariate analysis showed that N stage(OR=0.525, 95% CI: 0.309-0.891, P=0.017), location of the tumor (OR=1.770, 95% CI:1.115-2.812, P=0.016) and preoperative neoadjuvant radiotherapy (OR=1.976, 95% CI:1.228-3.401, P=0.006) were the independent risk factors associated with the disease-free interval of metachronous pulmonary metastasis from rectal cancer.

CONCLUSIONS

Advanced N stage, low location of the tumor and no use of preoperative neoadjuvant radiotherapy are risk factors of shorter disease-free interval of metachronous pulmonary metastasis from rectal cancer.

[Analysis of risk factors associate with lymph node metastasis of T1 and T2 rectal cancer]

OBJECTIVE

To investigate the risk factors associated with lymph node metastasis of T1 and T2 rectal cancer.

METHODS

Clinicopathological data of 576 patients with stage T1 to T2 rectal cancer without serosal invasion confirmed by pathology undergoing curative resection in Changhai Hospital from January 1999 to December 2013 were analyzed retrospectively. The relationship of clinicopathological factors of overall patients and stage T1 patients with lymph node metastasis was analyzed by univariate or multivariate analysis.

RESULTS

The lymph node metastasis rate of stage T2 rectal cancer was significantly higher than that of stage T1[22.9% (108/463) vs. 9.7%(11/113), P=0.002], and the difference of stage T2a and T2b was not significant[22.0%(38/173) vs. 23.4% (68/290), P=0.733]. Multivariate analysis showed that poor differentiation(HR=1.54, 95% CI:1.12 to 2.13), abnormal carbohydrate antigen (CA) 199 level (HR=2.05, 95% CI:1.16 to 3.62), ulcerative mass (HR=1.58, 95% CI:1.05 to 2.39) and invasion of muscle (of inner ring muscle HR=3.55, 95% CI:1.79 to 7.02; of outer longitudinal muscle, HR=2.35, 95% CI:1.21 to 4.60) were independent risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer(all P<0.05). Meanwhile poor differentiation(HR=4.43, 95% CI:1.51 to 13.03), abnormal carcinoembryonic antigen(CEA) level (HR=4.66, 95% CI:1.18 to 20.11) and ulcerative mass (HR=6.23, 95% CI:1.51 to 25.66) were risk factors of lymph node metastasis in patients with stage T1 rectal cancer.

CONCLUSION

Poor differentiation, preoperative high CA199, ulcerated tumor, invasion of inner ring muscle or outer longitudinal muscle are risk factors of lymph node metastasis in patients with stage T1-T2 rectal cancer, while the invasion depth of muscularis propria is not risk factor. Besides, poor differentiation, abnormal CEA level, ulcerated tumor are risk factors of lymph node metastasis in stage T1 rectal cancer patients, which can be used as reference for local excision in patients with stage T1 rectal cancer.

[Practice and investigation of clinical teaching mode of standardized treatment in colorectal cancer for fellows in training]

A new clinical teaching mode of standardized treatment in colorectal cancer for fellows in training is reported here with good results. This one-year program included medical ethics education, humanistic management, pre job training, clinical thinking mode, surgery teaching, and computerized teaching. This new clinical teaching mode with distinct features is effective and introduced in this article.

[Association of microRNA101 expression with clinicopathologic features and prognosis in colorectal cancer]

OBJECTIVE

To investigate the microRNA101(miR101) expression and its clinical significance in colorectal cancer.

METHODS

Tissue microarrays containing 56 specimens of normal mucosa, 51 adenoma and 735 colorectal cancer were examined by locked nucleic acid in-situ hybridization(LNA-ISH) for miR101 expression. Relationship between miR101 expression and clinicopathologic parameters and prognosis of colorectal cancer patients were analyzed. Fresh frozen tissues containing 5 specimens of normal mucosa, 5 adenoma and 47 colorectal cancer were examined by RT-PCR to verify the accuracy of LNA-ISH.

RESULTS

Expression of miR101 increased gradually from normal mucosa, adenoma to stage I colorectal cancer (all P<0.01), and decreased gradually from stage II(, stage III( to stage IIII( colorectal cancer (all P<0.01). Overexpression of miR101 was related with lower incidence of lymph node metastasis, lower metastasis rate, higher differentiation and lower recurrence rate (all P<0.01). Multivariate survival analysis demonstrated that miR101 expression was an independent prognostic factor of overall survival (HR=0.550, 95% CI: 0.351-0.863) and disease free survival(HR=0.562, 95% CI: 0.397-0.794) in colorectal cancer patients. Overexpression of miR101 predicted a better prognosis in colorectal cancer patients.

CONCLUSIONS

Expression of miR101 is associated with the genesis and development of colorectal cancer, and may serve as an independent prognostic factor for colorectal cancer patients.

Colonoscopy is the first choice for early postoperative rectal anastomotic bleeding

Background

Anastomotic bleeding is rare but is one of the dangerous complications, with associated morbidity and mortality, at the early stage of rectal cancer surgery. The aim of this study was to report our experiences in the treatment of this emergency condition.

Methods

We retrospectively analyzed the general characteristics, treatment and outcome of patients with severe anastomotic bleeding after undergoing rectal cancer resection with stapled anastomosis at the Department of Colorectal Surgery of Changhai Hospital (China) between January 2011 and December 2013.

Results

Anastomotic bleeding occurred in six out of 2,181 patients (0.3%) who underwent anterior resection with stapled anastomosis due to rectal cancer. All patients’ bleeding was stopped with colonoscopic techniques. There were no anastomotic leakages or strictures in these six patients.

Conclusions

Anastomotic bleeding was a very rare complication after rectal cancer resection with stapled anastomosis. Colonoscopic treatment, including electrocoagulation and clipping, were both safely and effectively used in the early postoperative period to cease persistent anastomotic bleeding.

[Expression of long non-coding RNA associated with radiotherapy-resistance in colorectal cancer cell lines with different radiosensitivity]

OBJECTIVE

To screen long non-coding RNA (lncRNA) associated with radiosensitivity in colorectal carcinoma cell lines.

METHODS

Colony formation assay was performed in colorectal cancer cell lines HT29, SW480, RKO, Lovo and HCT116 after irradiation with different radiation doses. Radiation sensitivity of these 5 cell lines was detected through survival fraction at 2 Gy (SF2 value). High-throughput lncRNA chip was used to screen lncRNA genes with expression differences more than 2 folds among SW480, RKO and Lovo. Further experiment on the expression differences of lncRNAs selected was conducted by realtime PCR.

RESULTS

The radiosensitivity order of these 5 cell lines from low to high (SF2 value from high to low) was HT29 (0.83 ± 0.03), SW480 (0.69 ± 0.02), RKO(0.53 ± 0.02), Lovo (0.47 ± 0.05), HCT116 (0.32 ± 0.03) (P < 0.01). Five lncRNAs associated with radiation sensitivity were screened. Among them, expression levels of R05532, NR_015441, and NR_033374 were positively correlated with radiation resistance(all P < 0.01), and expression levels of the other 2 lncRNAs, NR_073156 and AA745020, were not correlated with radiation resistance of colorectal cancer cells (both P>0.05).

CONCLUSIONS

lncRNA R05532, NR_015441 and NR_033374 may be used as the predictive marker of radiosensitivity of colorectal cancer cells. Higher expression of these genes shows radiation resistance.

[Mechanism exploration and future prospects of antiangiogenic agents improving tumor blood supply and oxygenation]

The growth and metastasis of tumor is angiogenesis-dependent. Antiangiogenic agents have been clinically used to treat malignant tumors with the mechanisms of regressing tumor vasculature and inhibiting vascular recurrence which restrain tumor growth and metastasis. Clinical evidences indicate that antiangiogenic agents combined with chemotherapy or radiotherapy potentiate the effects of treatment. However, radiation therapy and chemotherapy depend on ample blood flow to the tumor to deliver oxygen and drugs. Theoretically, it is paradoxical with evidences that these therapies work together rather than against each other. "Vascular normalization" theory was raised to explain this paradox. And accumulating data show that antiangiogenic agents transiently "normalize" tumor vasculature before causing vascular regression, so that improve tumor blood supply and increase tissue oxygenation. New views and challenges about antiangiogenic agents come out with the discovery of "normalization window". In this review, we summarized the mechanism, related researches and future prospects of antiangiogenic agents improving blood supply and oxygenation.

Gene expression profiling-derived immunohistochemistry signature with high prognostic value in colorectal carcinoma

OBJECTIVE

Gene expression profiling provides an opportunity to develop robust prognostic markers of colorectal carcinoma (CRC). However, the markers have not been applied for clinical decision making. We aimed to develop an immunohistochemistry signature using microarray data for predicting CRC prognosis.

DESIGN

We evaluated 25 CRC gene signatures in independent microarray datasets with prognosis information and constructed a subnetwork using signatures with high concordance and repeatable prognostic values. Tumours were examined immunohistochemically for the expression of network-centric and the top overlapping molecules. Prognostic values were assessed in 682 patients from Shanghai, China (training cohort) and validated in 343 patients from Guangzhou, China (validation cohort). Median follow-up duration was 58 months. All p values are two-sided.

RESULTS

Five signatures were selected to construct a subnetwork. The expression of GRB2, PTPN11, ITGB1 and POSTN in cancer cells, each significantly associated with disease-free survival, were selected to construct an immunohistochemistry signature. Patients were dichotomised into high-risk and low-risk subgroups with an optimal risk score (1.55). Compared with low-risk patients, high-risk patients had shorter disease-specific survival (DSS) in the training (HR=6.62; 95% CI 3.70 to 11.85) and validation cohorts (HR=3.53; 95% CI 2.13 to 5.84) in multivariate Cox analyses. The signature better predicted DSS than did tumour-node-metastasis staging in both cohorts. In those who received postoperative chemotherapy, high-risk score predicted shorter DSS in the training (HR=6.35; 95% CI 3.55 to 11.36) and validation cohorts (HR=5.56; 95% CI 2.25 to 13.71).

CONCLUSIONS

Our immunohistochemistry signature may be clinically practical for personalised prediction of CRC prognosis.

[Cloning, expression and immuno-protection analysis of a gene encoding troponin T of Schistosoma japonicum (SjTnT)]

OBJECTIVE

To clone cDNA encoding troponin T of Schistosoma japonicum (SjTnT), and evaluate the protective efficacy induced by recombinant SjTnT in BALB/c mice against S. japonicum challenge infection.

METHODS

The SjTnT gene was amplified from 28-day-schistosome cDNAs by PCR and then subcloned into pET28a(+). The recombinant SjTnT protein (rSjTnT) was expressed in Escherichia coli BL21 (DE3) cells. The serum specific to rSjTnT was prepared by immunized BALB/c mice with the recombinant antigen, and the immunogenicity of rSjTnT was detected by Western blotting and ELISA. The immuno-protective efficacy induced by rSjTnT in BALB/c mice was evaluated according to the reduction in worm and egg counts.

RESULTS

The cDNA encoding SjTnT was successfully cloned and expressed in E. coli. Western blotting showed that rSjTnT had a good immunogenicity. The high level of specific IgG antibodies was detected, and 33.89% worm reduction and 43.94% liver egg reduction were obtained in mice vaccinated with rSjTnT combined with Seppic 206 adjuvant compared with those in the adjuvant control group.

CONCLUSIONS

rSjTnT could induce partial immuno-protection against S. japonicum infection in BALB/c mice. This study provided a basic for understanding the biological function of SjTnT.

[Comparison of oncologic clearance and long-term outcomes of laparoscopic surgery versus open surgery in radical resection of rectal cancer]

OBJECTIVE

To compare the oncologic clearance and long-term outcomes between laparoscopic surgery and open surgery in radical resection of rectal cancer.

METHODS

Clinicopathological and follow-up data of 1184 cases with rectal cancer undergoing radical resection from July 2005 to December 2011 were analyzed retrospectively. According to the surgical method, cases were divided into laparoscopy group (104 cases) and open group(1080 cases). Demographics, number of harvested lymph nodes, distance between distal margin and tumor, incidence of anastomotic complications, disease-free survival (DFS) and overall survival(OS) were compared between the two groups.

RESULTS

There were no significant differences in the number of harvested lymph nodes (15.5 vs. 14.4, P>0.05), length of distal margin (2.5 cm vs. 2.1 cm, P>0.05) and incidence of anastomotic complications (1.9% vs. 1.9%, P>0.05) between the two groups. And there were no significant differences in DFS and OS between the two groups (both P>0.05). The 3-year and 5-year DFS in laparoscopy group were 79.0% and 69.3%, and were 78.0% and 72.5% in open group. The 3-year and 5-year OS in laparoscopy group were 93.5% and 81.2%, which were 87.6% and 80.7% in open group. There were no significant differences in DFS and OS after stratification by TNM stage.

CONCLUSION

The oncologic clearance and long-term outcomes after laparoscopic surgery are comparable with open surgery in radical resection of rectal cancer.

[Application and evaluation of pouch configuration in rectal surgery]

Colonic pouch can improve fecal continence after low anterior resection in the short-term, but its superiority would disappear in the long-term (2 years after surgery), since fecal continence improves gradually with time in the non-pouch group. Furthermore, the incidence of incomplete defecation increases gradually with time, and a lot of patients would have difficulty in defecation and require long-term use of suppositories and enemas. Pouch enforcement will result in prolonged operation time and increased treatment cost. Therefore, the value of colonic pouch in low rectal anastomosis is being questioned, and its application diminishes gradually. For patients with ulcerative colitis (UC) or familial adenomatous polyposis (FAP) after total colectomy, ileal pouch anal anastomosis (IPAA) can reduce fecal frequency and improve patients' quality of life in both short-term and long-term, by increasing the volume of the neo-rectum and altering intestinal motility. For these reasons, IPAA is the first surgical choice for UC and FAP.

Lower rate of colonoscopic perforation: 110,785 patients of colonoscopy performed by colorectal surgeons in a large teaching hospital in China

BACKGROUND

Colonoscopic perforation (CP) has a low incidence rate. However, with the extensive use of colonoscopy, even low incidence rates should be evaluated to identify and address risks. Information on CP is quite limited in China.

OBJECTIVE

Our study aimed to determine the frequency of CP in colonoscopies performed by surgeons at a large teaching hospital in China over a 12-year period.

METHODS

A retrospective review of medical records was performed for all patients who had CPs from 1 January 2000 to 31 December 2012. Iatrogenic perforations were identified mainly by abdominal X-ray or computed tomography scan. Follow-up information of adverse events post-colonoscopy was identified from the colorectal surgery database of our hospital. Patients' demographic data, colonoscopy procedure information, location of perforation, treatment, and outcome were recorded.

RESULTS

A total of 110,785 diagnostic and therapeutic colonoscopy procedures were performed (86,800 diagnostic cases and 23,985 therapeutic cases) within the 12-year study period. A total of 14 incidents (0.012%) of CP were reported (seven males and seven females), of which nine cases occurred during diagnostic colonoscopy (0.01%) and five after therapeutic colonoscopy (three polypectomy cases, one endoscopic mucosal resection, and one endoscopic mucosal dissection). Mean patient age was 67.14 years. One case of CP (7.14%) after colonoscopy polypectomy was treated using curative colonoscopy endoclips. Other patients underwent operations: six cases (46.15%) of primary repair, four cases (28.57%) of resection with anastomosis, and two cases (15.38%) of resection without anastomosis. No obvious perforation was found in one patient (7.69%). Surgeons attempted to treat one case laparoscopically but eventually resorted to open surgery. The postoperative course was uncomplicated in eight cases (57.14%) and complicated in six cases (42.86%) but without mortality.

CONCLUSION

CP is a serious but rare complication of colonoscopy. A perforation risk of 0.012% was found in our study. The optimal management of CP remains controversial. Treatment for CP should be individualized according to the patient's condition, related devices, and surgical skills of endoscopists or surgeons. Selective measures such as colonoscopy without intravenous sedation and decrease of loop formation can effectively reduce rates of perforation.

Prognostic significance and molecular mechanism of ATP-binding cassette subfamily C member 4 in resistance to neoadjuvant radiotherapy of locally advanced rectal carcinoma

Background

Mechanism of radioresistance in rectal carcinoma remains largely unknown. We aimed to evaluate the predictive role of ATP-binding cassette subfamily C member 4 (ABCC4) in locally advanced rectal carcinoma and explore possible molecular mechanisms by which ABCC4 confers the resistance to neoadjuvant radiotherapy.

Methods

The expression of ABCC4 and P53 mutant in biopsy tissue specimens from 121 locally advanced rectal carcinoma patients was examined using immunohistochemistry. The factors contributing to 3-year overall survival and disease-free survival were evaluated using the Kaplan-Meier method and Cox proportional hazard model. Lentivirus-mediated small hairpin RNA was applied to inhibit ABCC4 expression in colorectal carcinoma cell line RKO, and investigate the radiosensitivity in xenograft model. Intracellular cyclic adenosine monophosphate concentration and cell cycle distribution following irradiation were detected.

Results

High expression of ABCC4 and p53 mutant in pretreated tumors, poor pathological response, and high final tumor staging were significant factors independently predicted an unfavorable prognosis of locally advanced rectal carcinoma patients after neoadjuvant radiotherapy. Down-regulation of ABCC4 expression significantly enhanced irradiation-induced suppression of tumor growth in xenograft model. Furthermore, down-regulation of ABCC4 expression enhanced intracellular cyclic adenosine monophosphate production and noticeable deficiency of G1-S phase checkpoint in cell cycle following irradiation.

Conclusions

Our study suggests that ABCC4 serves as a novel predictive biomarker that is responsible for the radioresistance and predicts a poor prognosis for locally advanced rectal carcinoma after neoadjuvant radiotherapy.

Abstract B14: Trends in academic publications on oncology in East Asia: A 10-year survey of the English literature in China, Japan and Korea

Background: The incidence and mortality of malignant diseases keep increasing in East Asia, especially in China. The research status on oncology in East Asia is largely unknown. The quality and quantity of academic publications can reflect the research activity. Here, we analyzed contributions of Japan, Korea and China in this field. Methods: We searched PubMed and Web of Science databases for articles published in oncology journals between 2003 and 2012. The total number of articles, citations, impact factors, and the number of articles published in high Impact Factor and the most popular oncology journals were compared among the contributing authors from Japan, Korea and China. Results: During the past decade from 2003 to 2012, 31,338 related articles were published in 96 oncology journals selected. The number of articles from China increased significantly, while there was a notable decline in Japan, and a modest increase in Korea, with an annual incremental rate of 24.97%, -1.69% and 12.66%, respectively. However, the accumulative IF of articles from Japan was higher than that from China (6298.8 vs. 3970.5, p = 0.059) and Korea (6298.8 vs. 2017.2, p = 0.005). Japanese oncologists contributed more publications to international oncology societies with respect to clinical trials, randomized controlled trials and case reports, and published more articles in top oncology journals as compared with China (1212 vs. 524, p = 0.015) and Korea (1212 vs. 344, p = 0.008). Conclusions: Although oncology research in China has been greatly improved over the past 10 years, there is still a significant gap between China and Japan with respect to high-level research on oncology. It is therefore an unshakable responsibility for Chinese oncologists to conduct high level original research and clinical trials on oncology, given China's big population and high cancer incidences.

Note:This abstract was not presented at the conference.

Citation Format: Zhiqi Yu, Junjie Xing, Yan Du, Hantao Wang, Guangwen Cao, Chuangang Fu. Trends in academic publications on oncology in East Asia: A 10-year survey of the English literature in China, Japan and Korea. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr B14.

Abstract B35: Aberrant expression of ABCC3 in rectal cancer predicts poor prognosis and pathological response to neoadjuvant chemoradiotherapy via activating the caspase-3 dependent apoptotic pathway

Objective: To clarify the role of ATP binding cassette subfamily C member 3 (ABCC3) on prognosis and pathological response to neoadjuvant chemoradiotherapy in rectal cancer, and further explore the potential molecular mechanism. Design: Retrospective analysis of clinicopathologic factors and detection of ABCC3 expression in pretreatment biopsy specimens from 144 cases of stage II–III rectal cancer who received neoadjuvant chemoradiotherapy and radical surgery. Pathological response according to tumor regression grade and long-term survival curve were further determined. ABCC3 expression was down-regulated using short interfering RNA in colorectal carcinoma cells HT-29 and SW-480. Cell proliferation and apoptosis in response to 5-fluorouracil or irradiation were examined using colony formation assay, single-hit multi-target model, flow cytometry and Hoechst 33342 staining, respectively. Tumor growth following fractional irradiation was measured in xenograft mouse model. Change of intracellular reactive oxygen species contents and activation of cleaved caspase-3 expression were further explored. Results: Aberrant expression of ABCC3 was an independent factor significantly predicting poor pathological response to neoadjuvant chemoradiotherapy (P=0.002) and prognosis (3-year Overall Survival: P=0.011; 3-year Disease-free Survival: P=0.003). Down-regulation of ABCC3 expression significantly increased 5-fluorouracil or irradiation induced cell apoptosis in vitro, and tumor growth was significantly suppressed following irradiations in vivo. Furthermore, inhibition of ABCC3 expression obviously activated caspase-3 dependent apoptotic pathway and decreased intracellular reactive oxygen species exporting from cells after being exposed to irradiations. Conclusion: ABCC3 is an attractive target for improving sensitivity to neoadjuvant chemoradiotherapy and of potential value for a clinical breakthrough in the comprehensive treatment of rectal cancer patients.

Note:This abstract was not presented at the conference.

Citation Format: Zhiqi Yu, Chang Zhang, Xianhua Gao, Junjie Xing, Hao Wang, Enda Yu, Wei Zhang, Xiaoqing Zhang, Guangwen Cao, Chuangang Fu. Aberrant expression of ABCC3 in rectal cancer predicts poor prognosis and pathological response to neoadjuvant chemoradiotherapy via activating the caspase-3 dependent apoptotic pathway. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr B35.

[Association of epithermal growth factor receptor expression and its downstream gene mutation status with radiosensitivity of colorectal carcinoma cell lines in vitro]

OBJECTIVE

To investigate the effect of epithermal growth factor receptor (EGFR) expression and K-ras, B-raf and PIK3CA mutation status on the radiosensitivity of human colorectal carcinoma (CRC) cell lines in vitro.

METHODS

Real-time RT-PCR was used to measure EGFR mRNA expression in nine human CRC cell lines, and K-ras, B-raf and PIK3CA mutation status of each CRC cell line was also identified respectively. After treatment with irradiation at graded dose, the cell viability was measured by clonogenic survival assay. The rate of cell apoptosis and cell cycle distribution were tested by flow cytometry. The cell morphology was observed with hoechst 33258 staining to analyze the correlation between EGFR mRNA expression and radiosensitivity of CRC cell lines.

RESULTS

A positive correlation between EGFR mRNA expression and survival fraction of 2 Gy(SF2) was observed (r=0.717, P=0.030). Association was also identified between the mutation status of PIK3CA and radiosensitivity (t=2.401, P=0.047), while mutation status of K-ras and B-raf was not associated with radiosensitivity. At 48-hour after exposing to irradiation, the apoptosis rate of radiosensitive cell line (HCT116) was significantly increased in a dose-dependent manner (P<0.05), while the apoptosis rate of radioresistant cell line (HT29) was significantly increased only when radiation dose increased to 6 Gy. The ratio of G0/G1 phase was reduced significantly with the increase of radiation dose in radiosensitive cell line (HCT116, P<0.05), while this trend was not observed in radioresistant cell line (HT29, P>0.05).

CONCLUSIONS

Over-expression of EGFR mRNA is correlated to radioresistance of human CRC cell lines, and mutation status of PIK3CA is closely related with radiosensitivity of CRC cells. The inhibition of apoptosis and G0/G1 arrest may induce the radioresistance of CRC cell lines.

Nuclear orphan receptor NR4A2 confers chemoresistance and predicts unfavorable prognosis of colorectal carcinoma patients who received postoperative chemotherapy

BACKGROUND

NR4A2, an orphan nuclear receptor essential in neuron generation, has been recently linked to inflammatory and metabolic pathways of colorectal carcinoma (CRC). However, the effects of NR4A2 on chemo-resistance and postoperative prognosis of CRC remain unknown.

METHODS

NR4A2 was transfected into CRC cells to investigate its effects on chemo-resistance to 5-fluorouracil and oxaliplatin and chemotherapeutics-induced apoptosis. We also investigated prostaglandin E2 (PGE2)-induced NR4A2 expression and its effect on chemo-resistance. Tissue microarrays including 51 adenoma, 14 familial adenomatous polyposis with CRC, 17 stage IV CRC with adjacent mucosa and 682 stage I-III CRC specimens were examined immunohistochemically for NR4A2 expression. Median follow-up time for stage I-III CRC patients was 53 months.

RESULTS

Ectopic expression of NR4A2 increased the chemo-resistance, and attenuated the chemotherapeutics-induced apoptosis. Transient treatment of PGE2 significantly up-regulated NR4A2 expression via protein kinase A pathway and increased the chemo-resistance. NR4A2 expression in epithelials consecutively increased from adenoma, adjacent mucosa to CRC (P(trend)<0.001). In multivariate Cox regression analyses, high NR4A2 expression in cancer nuclei (immunoreactive score ≥ 4) significantly predicted a shorter disease-specific survival (DSS) of CRC patients (hazard ratio [HR]=1.88, P=0.024). High NR4A2 expression specifically predicted a shorter DSS of colon cancer patients (dichotomisation, HR=2.55, log-rank test P=0.011), especially for those who received postoperative 5-fluorouracil/leucovorin plus oxaliplatin (FOLFOX) chemotherapy (3-score range, HR=1.86, log-rank test P=0.020).

CONCLUSION

High expression of NR4A2 in CRC cells confers chemo-resistance, attenuates chemotherapeutics-induced apoptosis, and predicts unfavorable prognosis of colon cancer patients, especially for those who received postoperative chemotherapy. NR4A2 may be prognostic and predictive for colon cancer.

[Surgical treatment strategies for locally advanced rectal cancer after neoadjuvant radiation]

For locally advanced rectal cancer after neoadjuvant radiation, it is difficult to make a choice between close observation, local resection, and radical resection. The decision should be made after carefully weighing postoperative complications, anal function, local recurrence and long-term survival. There is a high consistency of the radiosensitivity between primary tumor and mesenteric lymph node, which may be used to guide the treatment decisions. If the primary tumor shrinks significantly after neoadjuvant radiation, local resection is recommended, and the next treatment plan should be made based on the pathological examination of resected specimen. Transabdominal radical resection is recommended for unfavorable tumors. Distal resection margin should be at least 1 cm, and marking the inferior margin of tumor is also recommended before neoadjuvant radiation since it would shrink significantly after radiation.

[Emergence application of colonoscopic placement of self-expandable metal stent without fluoroscopic monitoring]

OBJECTIVE

To evaluate the efficacy and safety of colonoscopy-guided placement of self-expandable metallic stent without fluoroscopic monitoring in the emergence management for acute malignant colorectal obstruction.

METHODS

Clinical data of 42 patients (24 males and 18 females with a mean age of 64.3 years) undergoing colonoscopy-guided placement of self-expandable metallic stents without fluoroscopic monitoring for acute malignant colorectal obstruction between January 2010 and June 2012 were reviewed retrospectively.

RESULTS

The obstruction was located in the rectum (n=19), sigmoid (n=9), descending colon (n=8), splenic flexure (n=1), hepatic flexure (n=3), and ascending colon (n=2). Technical success was achieved in all the 42 patients (100%). The mean time of operation was (11.8±10.4) min (range 1.1-51.0 min). No serious procedure-related complication occurred. Minor bleeding occurred in 3 cases (7.1%). One patient died on the second day after surgery because of heart failure.

CONCLUSIONS

Colonoscopy-guided placement of self-expandable metallic stents without fluoroscopic monitoring in emergence management for acute malignant colorectal obstruction is effective and safe with shorter operative time.

[Colonoscopic restoration for sigmoid vovulus in the elderly]

OBJECTIVE

To investigate the emergency therapeutic strategy for sigmoid vovulus in the elderly.

METHODS

Clinical data of 14 elderly patients with sigmoid vovulus were analyzed retrospectively.

RESULTS

The mean age was(79.1±7.2) years(range, 70-93), and 11 patients (78.6%) were male. Emergency decompression and restoration with colonoscopy was performed in all the patients with a success rate of 100%. No patient required emergent surgery. Four patients(28.6%) recurred and they were managed well by repeat colonoscopic restoration.

CONCLUSION

Emergency colonoscopic restoration is the first treatment of choice for sigmoid vovulus in the elderly because it is safe and effective, and can be performed repeatedly.

[Competing endogenous RNA regulation mechanism and its role in the development and progression of colorectal cancer]

MicroRNAs are negative regulators of mRNA, and latest studies show that "mRNAs can also inhibit microRNAs". With these reciprocal interactions, different mRNAs with identical "microRNA binding site" cim regulate each other by competitively binding to the same microRNA pool. This is the novel competing endogenous RNA (ceRN A)regulating mechanism. The ceRN A mechanism, which is a totally new regulating mechanism , greatly expands the regulatory network across genes. It has been proved by experimental evidence that, in HCT116 colon cancer cells,KRAS and PTEN , ZEB2 and PTEN can regulate each other by ceRNA mechanism.

Treatment for early ultralow rectal cancer: pull-through intersphincteric stapled transection and anastomosis (PISTA) versus low anterior resection

BACKGROUND

The aim of this study was to compare the functional and oncologic results of pull-through intersphincteric stapled transection and anastomosis (PISTA) with low anterior resection (LAR) in the treatment for early ultralow rectal cancer.

METHODS

A total of 278 patients with early ultralow rectal cancer were retrospectively included and analyzed, with 136 in the PISTA group and 142 in the LAR group.

RESULTS

Gender, age, tumor diameter, distance from the dentate line to the inferior margin of the tumor, tumor stage, length of operation and postoperative complications were comparable in the two groups. Compared with the LAR group, the PISTA group had a more accurate distal transection site, a lower daily fecal frequency (6 (5-7) vs. 8 (7-9), p < 0.001) and a lower Wexner incontinence score (13 (10-14) vs. 14 (13-16), p < 0.001) 3 months after ileostomy reversal, and a higher rate of satisfactory fecal continence (97.1 % vs. 90.8 %, p = 0.043). The follow-up period of the PISTA group was similar to that of the LAR group (56 (30-81) months vs. 54 (30-80) months, p = 0.982). The PISTA group was associated with a lower local recurrence rate (2.2 % vs. 11.3 %, p = 0.003). Kaplan-Meier analysis also showed that the PISTA group was associated with longer overall survival (p = 0.018) and longer local recurrence-free survival (p = 0.004) than the LAR group, while distant metastasis-free survival (p = 0.896) was comparable in the two groups. Multivariate analysis identified lymph node metastasis (p < 0.001) and operation (PISTA vs. LAR, p = 0.031) as independent predictive factors for local recurrence-free survival.

CONCLUSIONS

PISTA is a technically simple, oncologically safe and functionally favorable procedure for the treatment for early ultralow rectal cancer.

More advanced or aggressive colorectal cancer is associated with a higher incidence of "high-grade intraepithelial neoplasia" on biopsy-based pathological examination

BACKGROUND

Invasion of submucosa (ISM) is required for the pathological diagnosis of colorectal cancer according to the WHO criteria. A large proportion of colorectal cancers may be underdiagnosed as high-grade intraepithelial neoplasia (HGIN) because ISM is not identified in the preoperative biopsy. The aim of this study was to investigate the clinicopathologic features that are associated with missing the diagnosis of ISM in biopsy specimens of invasive colorectal cancer.

METHODS

Three hundred and sixteen patients diagnosed with colorectal cancer between January 2007 and December 2008 with well-preserved preoperative biopsy specimens were enrolled in the study. Three hundred and eleven patients had an isolated lesion, and five had two lesions. Biopsy specimens were reevaluated by two senior pathologists. Clinicopathologic features, biopsy pathology and surgical pathology results of all patients were analyzed by univariate and multivariate analyses.

RESULTS

ISM was identified in 216 cases (67.3 %) by biopsy-based pathological examination, and missed in 105 (32.7 %) cases, 72 of which were diagnosed as HGIN. Univariate analysis indicated that in colorectal cancer patients with smaller biopsy specimens (P = 0.042), mucinous or signet-ring cell carcinoma (P = 0.003), higher WHO tumor grade (P = 0.001) and positive lymph nodes (P = 0.011), ISM was more likely to be missed. There was a trend toward an increased diagnosis of ISM with the increase in the number of biopsy specimens (P = 0.105). On multivariate logistic regression analysis, smaller biopsy specimens (OR, 1.810; 95 % CI, 1.081-3.032; P = 0.024) and higher WHO tumor grade (OR, 2.073; 95 % CI, 1.046-4.107; P = 0.037) were the only factors associated with failure to identify ISM.

CONCLUSIONS

A large number of invasive colorectal cancers are at risk of being underdiagnosed as HGIN by biopsy-based pathology. The smaller the biopsy size, the less likely it is that the muscularis mucosae is included in the specimen. Also, in the more advanced or aggressive colorectal cancers, ISM is more likely to be missed on biopsy, which may be due to the destruction of the muscularis mucosae by more aggressive cancers.